BPH-18-002

$HeadURL$ $Id$

BPH-18-002

# Measurement of the $\PgUa$ pair production cross section and search for
resonances decaying to $\PgUa\Pgm^{+}\Pgm^{-}$ in proton-proton collisions at
$\sqrt{s}=13\TeV$

###### Abstract

The fiducial cross section for pair production in proton-proton collisions at
a center-of-mass energy of 13in the region where both mesons have an absolute
rapidity below 2.0 is measured to be $79\pm 11\stat\pm 6\syst\pm
3~{}(\mathcal{B})$pb assuming the mesons are produced unpolarized. The last
uncertainty corresponds to the uncertainty in the meson dimuon branching
fraction. The measurement is performed in the final state with four muons
using proton-proton collision data collected in 2016 by the CMS experiment at
the LHC, corresponding to an integrated luminosity of 35.9. This process
serves as a standard model reference in a search for narrow resonances
decaying to $\PgUa\Pgm^{+}\Pgm^{-}$ in the same final state. Such a resonance
could indicate the existence of a tetraquark that is a bound state of two
quarks and two antiquarks. The tetraquark search is performed for masses in
the vicinity of four times the bottom quark mass, between 17.5 and 19.5, while
a generic search for other resonances is performed for masses between 16.5 and
27. No significant excess of events compatible with a narrow resonance is
observed in the data. Limits on the production cross section times branching
fraction to four muons via an intermediate resonance are set as a function of
the resonance mass.

##  0.1 Introduction

Quarkonium pair production is an important probe of both perturbative and
nonperturbative processes in quantum chromodynamics. Experimental studies of
this process can provide valuable information about the underlying mechanisms
of particle production and improve our understanding of numerous physics
processes that are treated as backgrounds in searches and measurements.
Quarkonium pairs may originate from single-parton scattering (SPS) or double-
parton scattering (DPS). These production mechanisms can be separated
experimentally since the DPS production is characterized, among other
features, by more forward and separated mesons. The analysis of
nonperturbative effects is easier for quarkonium states composed of quarks, as
their large masses allow them to be approximated as nonrelativistic systems
[1]. The CMS Collaboration observed for the first time the production of a
pair of mesons, using proton-proton data collected at a center-of-mass energy
of 8 [2]. This Letter presents a measurement of the pair production cross
section at a center-of-mass energy of 13. The cross section is measured in the
fiducial region where both mesons have an absolute rapidity below 2.0, using
the final state with four muons. Additionally, the DPS contribution to the
process is measured for the first time.

The pair production can serve as a reference in searches for tetraquarks or
generic resonances with masses close to twice the meson mass. A light
resonance decaying to a meson and a pair of leptons might be the signature of
a tetraquark characterized as a bound state of two quarks and two antiquarks,
especially if its mass is below twice the $\eta_{\cPqb}$ mass [3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13]. In this Letter, in addition to the measurement of the
pair production cross section, we describe a search for tetraquarks with
masses between 17.5 and 19.5, since $\cPqb\cPqb\cPaqb\cPaqb$ tetraquarks would
be expected to have a mass around four times that of the bottom quark. A
generic search for narrow resonances with mass between 16.5 and 27and decaying
to a meson and a pair of muons is also presented. The final state is the same
as for the measurement of the pair production cross section, and a similar
event selection is used. The pair production is a background to the resonance
search.

The LHCb Collaboration searched for $\cPqb\cPqb\cPaqb\cPaqb$ tetraquarks using
data collected at center-of-mass energies of 7, 8, and 13, without finding any
hint of a signal [14]. This analysis probes a kinematic region that is not
accessible with the LHCb detector and extends the covered mass range in the
context of the generic search.

The pair production fiducial cross section measurement and the resonance
search are based on proton-proton collision data collected in 2016 at a
center-of-mass energy of 13by the CMS experiment at the CERN LHC,
corresponding to an integrated luminosity of 35.9.

##  0.2 The CMS detector

The central feature of the CMS apparatus is a superconducting solenoid of 6m
internal diameter, providing a magnetic field of 3.8T. Within the solenoid
volume, there are a silicon pixel and strip tracker, a lead tungstate crystal
electromagnetic calorimeter, and a brass and scintillator hadron calorimeter,
each composed of a barrel and two endcap sections. Forward calorimeters extend
the pseudorapidity coverage provided by the barrel and endcap detectors. Muons
are detected in gas-ionization chambers embedded in the steel flux-return yoke
outside the solenoid. Events of interest are selected using a two-tiered
trigger system [15]. A more detailed description of the CMS detector, together
with a definition of the coordinate system used and the relevant kinematic
variables, can be found in Ref. [16].

Muons are measured in the range $\abs{\eta}<2.4$, with detection planes made
using three technologies: drift tubes, cathode strip chambers, and resistive
plate chambers. Matching muons to tracks measured in the silicon tracker
results in a relative resolution in the range 0.8–3.0% for muons with less
than 10 [17].

##  0.3 Simulated samples

The pair production signal is simulated using the 8.226 generator [18],
separately for the SPS and DPS mechanisms, under the assumption that the
mesons are produced unpolarized. The DPS sample is produced by generating two
hard interactions with color-singlet production of bottomonium states via
$\cPg\cPg\to\cPqb\cPaqb$ or color-octet production of bottomonium states via
$\cPq\cPaq\to\cPqb\cPaqb$. The invariant mass distribution of the meson pair
and of the rapidity separation between the mesons are used to extract the
fraction of DPS production, as detailed in Section 0.5. For this measurement,
the distributions of these variables for the SPS process are taken from the
next-to-leading-order (NLO*) calculation with a cutoff color-singlet mechanism
(CSM) [19, 20, 21] using HELAC-Onia 2.0.1 [22, 23].

The signal of a narrow resonance decaying to a meson and a pair of muons is
modeled using different physics assumptions depending on the nature of the
resonance:

  * •

a bottomonium state with the properties of the , assuming a phase-space decay
to a meson and a pair of muons, using the 8.226 generator;

  * •

a scalar particle produced in gluon fusion, using the JHUGen generator [24,
25, 26, 27];

  * •

a pseudoscalar particle produced in gluon fusion, using the JHUGen generator;

  * •

a spin-2 particle produced in gluon fusion, using the JHUGen generator.

The signals are generated assuming the narrow-width approximation. The sample
is used to model the tetraquark signal, for which no dedicated generator
exists. The other samples correspond to the signals in the generic search over
an extended mass range. For each model, four resonance mass values are
simulated: 14, 18, 22, and 26. Since the signal acceptance falls steeply
around and below 14in the simulated samples, the probed mass range in this
analysis is restricted to stay well above this mass threshold. The different
mass points are used to interpolate and extrapolate the signal model over the
whole mass range.

The generator with the tune CUETP8M1 [28] is used to model the parton shower
and hadronization processes. Generated events are processed through a
simulation of the CMS detector based on [29].

##  0.4 Event selection criteria

The event reconstruction is based on the particle-flow algorithm [30], which
identifies individual particle candidates using information from all the
individual subdetectors. Muons are reconstructed by combining information from
the silicon tracker and the muon system [17].

Events are selected with a trigger that requires the presence of three muons.
Among these muons, two must have an invariant mass compatible with a resonance
($8.5<m_{2\Pgm}<11.4\GeV$) at trigger level, and the dimuon vertex fit
probability, calculated using the $\chi^{2}$ and the number of degrees of
freedom of the fit, must be greater than 0.5%.

Offline, we require each event to have four reconstructed muons with
$\pt>2\GeV$ and $\abs{\eta}<2.4$. These muons are required to satisfy the
global or particle-flow muon identification criteria described in Ref. [17].
About 25% of simulated signal events and about 30% of data events have more
than four such muons. Possible combinations of four muon tracks are refit with
a constraint to come from a common vertex, and the $\chi^{2}$ probability of
the fit is determined. The combination of four muons with the largest
$\chi^{2}$ probability is chosen. For simulated signal events with more than
four reconstructed muons, the correct muons are chosen in about 98% of cases.
Among the four muons, at least three need to be associated with the trigger-
level objects. At least two muons must be associated with the objects that
passed the mass compatibility and vertex criteria of the trigger, and they are
paired together. If there are more than two such muons, which happens for 2 to
35% of simulated signal events depending on the resonance mass, those that
have opposite-sign (OS) charges and an invariant mass closest to the world-
average mass [31] are paired together.

After selecting the best combination of four muons with $\pt>2\GeV$, the
threshold is raised to 2.5for the selected muons. The final selection
requiring $\pt>2.5\GeV$ reduces the background from misidentified muons by
about a factor of two. The muons are required to satisfy the medium muon
identification criteria described in Ref. [17]. Both pairs of muons have to be
composed of OS muons. The vertex fit $\chi^{2}$ probability of the four muons
is required to be greater than 5%, whereas that of the candidate is required
to be above 0.5%, similar to the requirement already imposed at trigger level.
The muons are required to be separated from each other by at least $\Delta
R=\sqrt{\smash[b]{(\Delta\eta)^{2}+(\Delta\phi)^{2}}}=0.02$, where
$\Delta\eta$ and $\Delta\phi$ are the differences in pseudorapidity and
azimuthal angle between the muons. The positively (negatively) charged muon
from one of the pairs can be paired with the negatively (positively) charged
muon of the other pair to form so-called alternative pairs of OS muons. If one
of these alternative pairs has an invariant mass compatible with a particle
within two standard deviations of the experimental resolution, which ranges
between about 0.03 and 0.12depending on the muon pair kinematics, the event is
discarded from the analysis. Events are also discarded if they contain two OS
pairs of muons with invariant mass less than 4.

The selection criteria detailed above are common for the measurement of the
pair production cross section and the search for a resonant signal. The
criteria that differ between the measurement and the search are described in
the following. In the measurement of the pair fiducial cross section, the
reconstructed absolute rapidity of both muon pairs is required to be less than
2.0. In addition, for muons with $\abs{\eta}<0.9$, the threshold is raised to
3.5. Central muons with transverse momentum below 3.5have a high probability
of being absorbed in the calorimeter or undergoing significant multiple
scattering before reaching the muon detectors. This selection criterion
reduces the systematic uncertainty in the muon reconstruction related to the
detector simulation. It is, however, not used in the resonant search because
it would strongly reduce the signal acceptance for the lower-mass signal
range. In the resonance search, the invariant mass of the candidate is
required to be within two standard deviations of the experimental resolution
from the mass [31], where the resolution varies between about 0.06 and
0.15depending on the event.

The mass range of interest is known a priori for the search of a
$\cPqb\cPqb\cPaqb\cPaqb$ tetraquark signal. In this case, all the selection
criteria described above have been determined and fixed in a blinded way,
using simulation and without looking at data events with four muons having an
invariant mass between 17.5 and 19.5.

##  0.5 Measurement of the $\PgUa$ pair production cross section

The methodology used to measure the pair production cross section is detailed
in Section 0.5.1. After discussing the systematic uncertainties in Section
0.5.2, the results of the measurement of the inclusive pair production
fiducial cross section are presented in Section 0.5.3. Nonisotropic decays of
the mesons would change the measured cross section. Section 0.5.4 describes
how the cross section would vary for nonzero values of the polarization
parameters. Finally, the DPS and SPS mechanisms can be separated
experimentally by measuring the pair production cross section in bins of the
rapidity difference between the mesons, $\abs{\Delta y(\PgUa,\PgUa)}$, and of
the invariant mass of the meson pairs, $m_{\PgUa\PgUa}$. A measurement of the
DPS-to-inclusive cross section ratio in the fiducial region is presented in
Section 0.5.5.

###  0.5.1 Methodology

The pair production cross section is measured in the fiducial region where
both mesons have an absolute rapidity below 2.0. No other requirement is
applied to define the fiducial region. The fiducial cross section,
$\sigma_{\text{fid}}$, can be expressed as:

$\sigma_{\text{fid}}=\frac{N^{\text{corr}}}{\lumi\mathcal{B}^{2}},$ (1)

where $N^{\text{corr}}$ is the number of signal events corrected for the
acceptance and efficiency of the selection, $\lumi$ is the integrated
luminosity, and $\mathcal{B}$ stands for
$\mathcal{B}(\PgUa\to\Pgm^{+}\Pgm^{-})=(2.48\pm 0.05)\%$ [31], which is the
branching fraction of the meson decay to a pair of muons. To extract
$N^{\text{corr}}$ from the data, we perform an extended unbinned two-
dimensional (2D) maximum likelihood fit of the invariant mass distributions of
two OS muon pairs, where all events are weighted for the acceptance and
efficiency on an event-by-event basis by the weight $\omega$, defined as:

$\begin{split}&\omega=\big{[}A_{1}A_{2}\epsilon^{\text{reco}}_{1}\epsilon^{\text{reco}}_{2}\big{(}1-(1-\epsilon^{\text{vtx}}_{1})(1-\epsilon^{\text{vtx}}_{2})\big{)}\epsilon^{\text{evt}}\big{]}^{-1},\end{split}$
(2)

where the different terms are described below:

  * •

$A$, the probability for a meson with an absolute rapidity below 2.0 and
decaying to a pair of muons to have two muons in the geometrical acceptance of
the detector (muon $\abs{\eta}<2.4$); No strong correlation between the
acceptance values of the two mesons are found with a closure test described in
Section 0.5.2, and the total acceptance is therefore computed as the product
of the per-meson weights;

  * •

$\epsilon^{\text{reco}}$, the probability for a meson with an absolute
rapidity below 2.0 and decaying to a pair of muons each with $\abs{\eta}<2.4$
to have two reconstructed muons passing the identification and kinematic
criteria listed in Section 0.4;

  * •

$\epsilon^{\text{vtx}}$, the probability for a meson passing the acceptance
reconstruction criteria outlined in items 2 and 3 to have a vertex fit
$\chi^{2}$ probability above 0.5%;

  * •

$\epsilon^{\text{evt}}$, the probability for an event where both candidates
pass all the criteria of items 2 and 3, and at least one of them passes the
vertex fit $\chi^{2}$ probability criterion of item 4, to pass the following
event-level criteria: the trigger requirements, the four-muon vertex fit
$\chi^{2}$ probability above 5%, and the absence of OS dimuon pairs with an
invariant mass within two standard deviations of the world-average meson mass
[31].

The first three items in the above list are calculated as a function of the
rapidity and . The values of $A$, $\epsilon^{\text{reco}}$, and
$\epsilon^{\text{vtx}}$, range between 0.47 and 1.00, 0.23 and 0.88, and 0.81
and 0.98, respectively, depending on the rapidity and . The factor
$\epsilon^{\text{evt}}$ is calculated as a function of the of both candidates,
and ranges between 0.33 and 0.65. The subscript indices in Eq. (2) indicate
the candidate to which the weight corresponds. The factor
$\epsilon^{\text{vtx}}$ enters the formula differently from the other
acceptance and efficiency terms because the dimuon vertex fit $\chi^{2}$
probability criterion needs to be satisfied by at least one of the two
candidates, but not necessarily by both. The weight $\omega$ is computed on an
event-by-event basis, using the kinematic quantities of the reconstructed
candidates in data. They are estimated from simulation as efficiency maps and
are similar for the SPS and DPS production modes, despite different
correlations between the mesons. Data-to-simulation corrections for the
trigger and muon identification efficiencies are taken into account in the
computation of $N^{\text{corr}}$.

In about 3% of cases, the four reconstructed muons are not correctly paired in
the SPS and DPS pair simulations. These events cannot be identified as part of
the signal by the 2D fit since their distribution is similar to that of the
floating combinatorial background. Therefore, the value $N^{\text{corr}}$
extracted from the fit is corrected by $+3\%$ to take into account these
mispairings.

In the 2D fit, the muons are paired as described in Section 0.4, and the
invariant masses of the two pairs are randomly denoted $m_{\text{12}}$ and
$m_{\text{34}}$. The signal model corresponds to $\PgUa+\PgUa$ events, whereas
the background model is the sum of the following physics processes:

  * •

$\PgUb+\PgUb$;

  * •

$\PgUc+\PgUc$;

  * •

$\PgUb+\PgUa$;

  * •

$\PgUc+\PgUa$;

  * •

$\PgUa+\textrm{combinatorial background}$;

  * •

$\PgUb+\textrm{combinatorial background}$;

  * •

$\PgUc+\textrm{combinatorial background}$;

  * •

combinatorial background + combinatorial background.

The shape of the invariant mass distribution for the component is determined
from a 2D fit of the two dimuon invariant masses in the pair SPS simulation.
The results are verified to be compatible with those of a fit performed using
the simulated DPS events, even if the muon rapidity distributions differ
between production modes. The $m_{\text{12}}$ and $m_{\text{34}}$
distributions are fitted with the sum of two same-mean Crystal Ball functions,
which correspond to a power law tail added to a Gaussian core. This allows the
radiative tails of the distributions to be well modeled. Figure 1 shows the
projection of the 2D fit on the $m_{\text{12}}$ axis for $\PgUa\PgUa$
simulated events. The projection on the $m_{\text{34}}$ axis is statistically
identical and therefore not shown. The fitted mean of the Crystal Ball
functions in simulation is compatible within one standard deviation with the
world-average mass of the meson, while the full width at half maximum is about
0.19, which is several orders of magnitude larger than the world-average width
of the meson [31] because of the limited detector resolution.

The contributions from and mesons are small, and the dimuon invariant mass
distributions for these mesons are taken from a control region in data with
events with two muons and two additional tracks that do not correspond to muon
candidates. Both processes are modeled with a Gaussian function.

Figure 1: Projection of the 2D fit (line) to the $m_{\text{12}}$ invariant
mass distribution (points) for the SPS $\PgUa\PgUa$ simulation. The vertical
bars on the points show the statistical uncertainty only. The mass
distribution is modeled with the sum of two Crystal Ball functions with the
same mean.

The combinatorial background components in the $m_{\text{12}}$ and
$m_{\text{34}}$ distributions are modeled with second-order Chebychev
polynomials with identical parameters. The number of degrees of freedom has
been determined with a Fisher F-test [32], where the distribution of the
combinatorial background is found by inverting the muon pair association in
the signal region. The parameters of the polynomial are free to float in the
2D fit to data in the signal region, detailed in Section 0.5.3.

In the 2D fit to the data performed in the signal region, the free parameters
are the normalizations of all the processes and the parameters of the
combinatorial background mass distribution. The function parameters of the , ,
and signal shapes are constrained within their uncertainties.

###  0.5.2 Systematic uncertainties

The normalization uncertainties that affect the measurement are the following:

  * •

2.5% uncertainty in the integrated luminosity for the 2016 running period
[33], which appears in Eq. (1).

  * •

0.5% uncertainty per muon in the efficiency of the muon identification and
tracking, measured with a tag-and-probe method [17]. It sums up to 2% per
event because the uncertainties are assumed to be correlated for the four
muons since they mostly originate from the same source. This uncertainty is
related to the term $\epsilon^{\text{reco}}$ in the weight $\omega$.

  * •

1% uncertainty in the vertex fit $\chi^{2}$ probability criterion, determined
by comparing background-subtracted observed and simulated distributions of the
vertex fit $\chi^{2}$ probability for events with a meson and two nearby
tracks. This uncertainty is related to the term $\epsilon^{\text{vtx}}$ in the
weight $\omega$.

  * •

2% uncertainty per muon matched to trigger objects in the trigger efficiency,
measured with a tag-and probe method, summing up to 6% per event because the
uncertainties are assumed to be correlated for the three muons required at
trigger level. This uncertainty is related to the term $\epsilon^{\text{evt}}$
in the weight $\omega$.

These normalization uncertainties propagate directly into identical
uncertainties in the pair production cross section. Additionally, the
uncertainty of 2% in the $\mathcal{B}(\PgUa\to\Pgm^{+}\Pgm^{-})$ branching
fraction, which is used to compute $N^{\text{corr}}$ based on Eq. (1), results
in a 4% uncertainty in the pair production cross section measurement.

The parameters of the combinatorial background are freely floating, while the
parameters of the $\PgUa\PgUa$ distributions are constrained within the
uncertainties obtained from the fit to simulated events. An uncertainty of
0.2% in the muon momentum scale is propagated as an uncertainty in the mean of
the model. These uncertainties in the signal and background model together
contribute an uncertainty of 1.5% in the pair production cross section
measurement.

The consistency of the method to obtain $N^{\text{corr}}$ is checked by
applying the efficiency and acceptance weights to the events selected in
simulation, and comparing the computed $N^{\text{corr}}$ to the number of
events generated in the fiducial region before applying any selection
criterion. This test is performed for both the SPS and DPS simulations using
the correction maps derived from one sample, the other one, or their
combination. Using the combined map, the weighted DPS yield has a deviation of
$(-1.3\pm 3.7)\%$ with respect to the generated yield, and the corresponding
deviation for the SPS sample is $(-0.6\pm 1.5)\%$. The level of closure is
similarly good for both production modes despite average event weights
differing by more than a factor of 3 because of the kinematic differences. The
weighted number of data events used to compute the pair production cross
section is increased by 1% to allow for a potential nonclosure, and an
uncertainty of 1.5% is associated with this correction.

The systematic uncertainties are summarized in Table 0.5.2.

Systematic uncertainties considered in the pair production cross section
measurement. The last column gives the associated absolute uncertainty in the
measurement of $\sigma_{\text{fid}}$.  Uncertainty source Uncertainty (%)
Impact on $\sigma_{\text{fid}}$ (pb) Integrated luminosity 2.5 2.0 Muon
identification 2.0 1.6 Trigger 6.0 4.7 Vertex probability 1.0 0.8
$\mathcal{B}(\PgUa\to\Pgm^{+}\Pgm^{-})$ 4.0 3.2 Signal and background models
1.2 1.0 Method closure 1.5 1.2 Total 8.1 6.4

###  0.5.3 Measurement of the fiducial cross section

The 2D unbinned fit to the $m_{\text{12}}$ vs. $m_{\text{34}}$ distribution
yields $N^{\text{corr}}=1740\pm 240$ for the $\PgUa\PgUa$ process. The
projections on both dimensions with all the fit components are shown in Fig.
2. This number of events can be translated into an inclusive cross section for
the $\PgUa\PgUa$ process in the fiducial region defined such that both mesons
have an absolute rapidity below 2.0. Taking into account the statistical and
systematic uncertainties described in Section 0.5.2, and assuming unpolarized
mesons, the inclusive fiducial cross section is measured to be:

$\sigma_{\text{fid}}=79\pm 11\stat\pm 6\syst\pm 3~{}(\mathcal{B})\ \unit{pb},$
(3)

where the last uncertainty comes from the uncertainty in the dimuon branching
fraction.

Figure 2: The two projections and the result of the 2D fit to the muon pair
invariant masses. Each event is corrected for acceptance and efficiency. The
pair production signal is shown as a filled area. The contributions from the
combinatorial background, and from events with a meson and a pair of
combinatorial muons, with a meson and two reconstructed muons from any origin,
and with a meson and two reconstructed muons from any origin, are overlaid.

The CMS Collaboration previously measured, in the same fiducial region, the
$\PgUa\PgUa$ production cross section at a center-of-mass energy of 8to be
$69\pm 13\stat\pm 7\syst\pm 3(\mathcal{B})$pb [2]. Assuming all uncertainties
are uncorrelated with those in the result presented in this Letter except that
in the branching fraction of the meson to muons, the measured ratio of the
cross section at a center-of-mass of 13to that at 8is $1.14\pm 0.32$, where
the uncertainty includes both the statistical and systematic components. The
generator predicts a ratio of 2.1 for DPS production, and 1.6 for the SPS
production. Taking the fraction of the DPS mechanism in the total cross
section $f_{\text{DPS}}=(39\pm 14)\%$ at a center-of-mass energy of 13, as
measured in Section 0.5.5, the cross section ratio predicted by is $1.79\pm
0.27$. Combining the uncertainties in quadrature, the prediction is within two
standard deviations of the measurement.

Another unbinned extended maximum likelihood fit is performed to extract the
number of $\PgUa\PgUa$ events observed in data after the selection. The
$\PgUa\PgUa$ unweighted signal yield is obtained from a fit where all observed
events have a weight of 1.0. For this fit, a separate signal shape is
determined by fitting the $m_{\text{12}}$ and $m_{\text{34}}$ distributions in
the unweighted simulation. The absence of weighting does not significantly
modify the signal distribution. The unweighted event yields are given for all
processes in Table 0.5.3. There is no evidence for the simultaneous production
of two excited states of the meson, but excesses with a significance lower
than two standard deviations indicate the possible presence of $\PgUa\PgUb$
and $\PgUa\PgUc$ events. The number of events from data in the $m_{\text{12}}$
vs. $m_{\text{34}}$ distribution is shown in Fig. 3, along with the results of
the fit to the signal+background model, using the color scale to the right of
the plot.

The unweighted number of events for each of the processes from the fit to the
$m_{\text{12}}$ and $m_{\text{34}}$ distributions without acceptance nor
efficiency corrections.  Process Uncorrected yield $\PgUa+\PgUa$ $111\pm 16$
$\PgUb+\PgUb$ $3.6~{}^{+4.4}_{-3.6}$ $\PgUc+\PgUc$ $1.1~{}^{+1.4}_{-1.1}$
$\PgUa+\text{combinatorial}$ $166\pm 33$ $\PgUb+\text{combinatorial}$ $25\pm
18$ $\PgUc+\text{combinatorial}$ $1.1~{}^{+11}_{-1.1}$ $\PgUb+\PgUa$ $19\pm
10$ $\PgUc+\PgUa$ $17\pm 11$ Combinatorial + combinatorial $561\pm 41$

Figure 3: The number of data events in each $0.6\GeV\times 0.6\GeV$ bin of the
$m_{\text{12}}$ vs. $m_{\text{34}}$ distribution is shown. The results of the
maximum-likelihood fit to the signal+background model are given by the colors,
using the color scale to the right of the plot.

###  0.5.4 Effect of the polarization

The acceptance and efficiency corrections have been computed assuming
negligible polarization of the mesons. A different assumption on the
polarization can change the measured fiducial cross section. The polarization
of the states affects the angular distributions of the leptons produced in the
$\PgUa\to\Pgm^{+}\Pgm^{-}$ decays through the following formula [34]:

$\frac{\rd^{2}N}{\rd\cos\theta~{}\rd\phi}\propto\frac{1}{3+\lambda_{\theta}}(1+\lambda_{\theta}\cos^{2}\theta+\lambda_{\phi}\sin^{2}\theta\cos
2\phi+\lambda_{\theta\phi}\sin 2\theta\cos\phi),$

where $\theta$ and $\phi$ are the polar and azimuthal angles, respectively, of
the positively charged muon with respect to the $z$ axis of a polarization
frame, and $\lambda_{\theta}$, $\lambda_{\phi}$, and $\lambda_{\theta\phi}$
are the angular distribution parameters. To estimate the effect of the
polarization on the measurement of the $\PgUa\PgUa$ fiducial cross section, we
choose to use the helicity frame, where the polar axis coincides with the
direction of the momentum. Measurements performed by the CMS and LHCb
Collaborations on single $\PgU$ production indicate compatibility of all the
angular distribution parameters with zero over a large phase space [35, 36].
However, the same may not be true for pair production. To estimate the effect
of polarization on the pair production cross section, simulated events are
reweighted to have the angular distributions corresponding to various
$\lambda_{\theta}$ values, without changing the overall simulated yield. The
same efficiency and acceptance corrections as in Eq. (2) are used to calculate
$N^{\text{corr}}$ for these different polarization scenarios. The variations
in the measured pair production cross section are given for different
$\lambda_{\theta}$ coefficients in Table 0.5.4. The effect of different
polarizations can be substantial, changing the measured cross section by $-60$
to $+25\%$.

Variation of the measured fiducial pair production cross section for several
$\lambda_{\theta}$ coefficient values.  $\lambda_{\theta}$ $-1.0$ $-0.5$
$-0.3$ $-0.1$ $+0.1$ $+0.3$ $+0.5$ $+1.0$ $\Delta\sigma_{\text{fid}}$ $-60\%$
$-22\%$ $-12\%$ $-3.7\%$ $+3.4\%$ $+9.4\%$ $+14\%$ $+25\%$

###  0.5.5 Measurement of the DPS-to-inclusive fraction

The DPS and SPS mechanisms lead to different kinematic distributions for the
$\PgUa\PgUa$ events. The DPS production is characterized by a larger
separation in rapidity between the mesons, $\abs{\Delta y(\PgUa,\PgUa)}$, as
they are largely uncorrelated, and by a larger invariant mass of the meson
pairs, $m_{\PgUa\PgUa}$. The distributions of $\Delta\phi(\PgUa,\PgUa)$,
$\Delta R(\PgUa,\PgUa)$, and $\pt(\PgUa\PgUa)$ also differ for the SPS and DPS
mechanisms, but they are very sensitive to the choice of model parameters in
the simulation and are subject to large theoretical uncertainties [37].
Measuring the $\PgUa\PgUa$ fiducial cross section in bins of $\abs{\Delta
y(\PgUa,\PgUa)}$ or of $m_{\PgUa\PgUa}$ can give a measurement of the fraction
of DPS events, $f_{\text{DPS}}$, defined as:

$f_{\text{DPS}}=\frac{\sigma_{\text{fid}}^{\text{DPS}}}{\sigma_{\text{fid}}^{\text{SPS}}+\sigma_{\text{fid}}^{\text{DPS}}},$
(4)

where $\sigma_{\text{fid}}^{\text{DPS}}$ and
$\sigma_{\text{fid}}^{\text{SPS}}$ are, respectively, the DPS and SPS cross
sections in the fiducial region. We measure the fiducial cross section in five
bins of $\abs{\Delta y(\PgUa,\PgUa)}$ and five bins of $m_{\PgUa\PgUa}$. The
signal and background models are the same as for the inclusive measurement,
except that the width of the function describing the invariant mass shape is
allowed to float between its best-fit values for the inclusive selection and
for the selection in the relevant exclusive bin. This allows for a potential
degradation (improvement) of the muon momentum resolution at high (low)
pseudorapidity to be taken into account, since the muon pseudorapidity is
correlated with both $\abs{\Delta y(\PgUa,\PgUa)}$ and $m_{\PgUa\PgUa}$. The
systematic uncertainties are identical to those presented in Section 0.5.2.

The extracted fiducial cross sections as a function of $\abs{\Delta
y(\PgUa,\PgUa)}$ and $m_{\PgUa\PgUa}$ are compared to the expected
distributions for SPS and DPS production, as obtained in the fiducial region
using for the DPS process, and from HELAC-Onia with the NLO* CSM predictions
for the SPS process. The fraction $f_{\text{DPS}}$ is measured with a binned
maximum-likelihood fit of these two simulated distributions with floating
normalizations to the measured fiducial cross sections in bins of $\abs{\Delta
y(\PgUa,\PgUa)}$ and $m_{\PgUa\PgUa}$. As determined from pseudo-experiments,
the best precision is expected to be achieved using $\abs{\Delta
y(\PgUa,\PgUa)}$. Theoretical uncertainties coming from the choice of parton
distribution functions and the factorization and renormalization scales are
taken into account for both the SPS and DPS predicted distributions. The
fraction $f_{\text{DPS}}$ is measured to be $(39\pm 14)\%$ using $\abs{\Delta
y(\PgUa,\PgUa)}$ as the discriminative distribution. This results includes
both statistical and systematic uncertainties, where the former strongly
dominates. The result using $m_{\PgUa\PgUa}$ is compatible with this
measurement, but with much lower precision: $(27\pm 22)\%$. The uncertainties
are strongly dominated by the uncertainties in the measurements of the cross
section in the $\abs{\Delta y(\PgUa,\PgUa)}$ and $m_{\PgUa\PgUa}$ bins, with
theoretical uncertainties in the predicted SPS and DPS distributions playing a
role at the percent level. The measured differential fiducial cross sections
are shown in Fig. 4, together with the SPS and DPS predictions.

Figure 4: Measured fiducial cross section (black dots) in bins of $\abs{\Delta
y(\PgUa,\PgUa)}$ (left) or $m_{\PgUa\PgUa}$ (right). The last bin includes the
overflow. The SPS and DPS distributions predicted from simulation are overlaid
using the $f_{\text{DPS}}$ value extracted from the fit to the $\abs{\Delta
y(\PgUa,\PgUa)}$ distribution. The shaded areas around the SPS and DPS
predictions indicate the theoretical uncertainties, which are often smaller
than the thickness of the dashed lines. The shaded area around the total
distribution corresponds to the uncertainty in the measurement of
$f_{\text{DPS}}$. The solid line shows the sum of the SPS and DPS
contributions with the best-fit $f_{\text{DPS}}$.

##  0.6 Search for resonances

###  0.6.1 Methodology

We search for a narrow excess of events above an expected smooth four-muon
invariant mass spectrum. Assuming that the resonant state decays into two
muons and a meson that further decays to a pair of muons, the signal mass
resolution can be improved by using a mass-difference observable [38]:

$\widetilde{m}_{\mathrm{4}\Pgm}=m_{\mathrm{4}\Pgm}-m_{\Pgm\Pgm}+m_{\PgUa},$
(5)

where $m_{\mathrm{4}\Pgm}$ is the invariant mass of the four leptons,
$m_{\Pgm\Pgm}$ the invariant mass associated with the candidate, and
$m_{\PgUa}$ the nominal mass of the particle (9.46 [31]). This estimated mass,
denoted as $\widetilde{m}_{\mathrm{4}\Pgm}$, has a resolution about 50% better
than the four-muon invariant mass $m_{\mathrm{4}\Pgm}$ for signal events. The
$m_{\mathrm{4}\Pgm}$ and $\widetilde{m}_{\mathrm{4}\Pgm}$ distributions are
similar for the combinatorial background.

The results are extracted by performing an unbinned maximum-likelihood fit to
the $\widetilde{m}_{\mathrm{4}\Pgm}$ spectrum. The signal and background
components are modeled by several functional forms in the fit, as described in
the next paragraphs.

The signal distributions are parameterized by the sum of two Gaussian
functions with the same mean. The parameters are extracted for the four mass
points available in simulation. The signal modeling needs to be interpolated
for masses between 16.5 and 26and extrapolated to masses up to 27to search for
narrow resonances with any mass between 16.5 and 27. This is done by fitting
with polynomials the different parameters of the two Gaussian functions as a
function of the generated resonance mass. The same procedure is repeated for
every signal model. The full width at half maximum is about 0.2for a resonance
mass of 18.

The background is separated into two components: the $\PgUa\PgUa$ process,
which was the signal in Section 0.5 and is characterized by a sharp rising
edge in the $\widetilde{m}_{\mathrm{4}\Pgm}$ spectrum at twice the meson mass,
and the combinatorial background, which is described by a smooth function as
explained below.

The $\widetilde{m}_{\mathrm{4}\Pgm}$ spectrum for the $\PgUa\PgUa$ process is
obtained from simulation, and is modeled as the product of a sigmoid function
and an exponential function with a negative exponent. The nominal model for
the $\PgUa\PgUa$ background is taken as an average between the DPS and SPS
templates, which is consistent with the measurement of the DPS fraction
presented in Section 0.5.3. Figure 5 shows the
$\widetilde{m}_{\mathrm{4}\Pgm}$ models obtained from simulated DPS and SPS
events, together with the average fit model. The number of $\PgUa\PgUa$ events
in the signal region is extracted, as detailed in Section 0.5, using the
selection designed for the resonance search and without applying the
acceptance and efficiency corrections from Eq. (2). In this case, only events
with $13<\widetilde{m}_{\mathrm{4}\Pgm}<28\GeV$ are retained and no rapidity
criteria are applied for the reconstructed candidates. The yield is measured
to be $78\pm 13$ events. The requirement that the mass of a dimuon pair is
compatible with the mass of a meson within two standard deviations is enforced
in the resonance search but is not applied to extract the yield because the 2D
fit relies on the mass tails to estimate the combinatorial background. Since
the efficiency of this criterion is 95% in both the SPS and DPS $\PgUa\PgUa$
simulations, the $\PgUa\PgUa$ yield in the signal region is corrected to
$74\pm 13$. The normalization of the pair production process and its
uncertainty are extracted from the same data as in the signal region of the
resonance search, but this does not lead to a significant overconstraint of
the uncertainty in the maximum-likelihood fit of the
$\widetilde{m}_{\mathrm{4}\Pgm}$ distribution because the latter can determine
the pair normalization only with poor precision.

Figure 5: Distributions of $\widetilde{m}_{\mathrm{4}\Pgm}$ for simulated
$\PgUa\PgUa$ events. The dashed lines are the best-fit models for the SPS and
DPS simulations. The solid line is the average of the SPS and DPS models,
which is taken as the nominal model for the $\PgUa\PgUa$ background in the
resonance search.

The $\widetilde{m}_{\mathrm{4}\Pgm}$ spectrum for the combinatorial background
is obtained in the fit to the data in the signal region. Several generic
functions are used to parameterize this smooth background:

  * •

Chebychev polynomials of various orders;

  * •

the sum of a Gaussian function and a Chebychev polynomial;

  * •

the sum of a Breit–Wigner function and a Chebychev polynomial.

The widths of the Gaussian and Breit–Wigner functions are constrained to be
above 2to avoid fitting narrow structures due to statistical fluctuations. We
verify, using a control region where the vertex fit $\chi^{2}$ probability of
the four muons is in the range $10^{-10}$–$10^{-3}$, that these three
functional forms describe the smooth $\widetilde{m}_{\mathrm{4}\Pgm}$ spectrum
of the combinatorial background with a good $\chi^{2}$ probability. Muons with
a vertex probability in this range are likely to be associated with processes
from the same primary vertex, but can originate from decays in flight or
displaced secondary vertices. This control region is shown in Fig. 6 for
illustrative purposes. The parameters of the functions determined from the fit
are not used in the signal region, where the parameters of the combinatorial
background, as well as the choice of the functional form, are freely floating.

Figure 6: Distributions of $\widetilde{m}_{\mathrm{4}\Pgm}$ for the
combinatorial background in a control region with the vertex fit $\chi^{2}$
probability of the four muons in the range $10^{-10}$–$10^{-3}$. The
parameters obtained in this fit are not used as an input for the fit in the
signal region. The functional forms for the combinatorial background shown by
the lines are all considered as possible shapes for the background model in
the likelihood fit. The order of the polynomials is indicated in parentheses
in the legend.

###  0.6.2 Systematic uncertainties

The systematic uncertainties are to a large extent similar to those used in
the measurement of the $\PgUa\PgUa$ cross section and introduced in Section
0.5.2. In this section, only the differences are highlighted. They arise from
slightly different selection criteria, a different choice of observable, the
treatment of the $\PgUa\PgUa$ process as a background, and the introduction of
a new signal process.

The uncertainty per muon in the muon identification and tracking is increased
from 0.5% to 1% because poorly reconstructed muons with $\pt<3.5\GeV$ in the
barrel are included in the resonance search to increase the signal acceptance
for light resonances. In addition, in the resonance search, the signal is
affected by a 1% yield uncertainty related to the requirement that the
candidate has an invariant mass compatible with the nominal meson mass within
two standard deviations. This uncertainty is determined by comparing the
dimuon invariant mass resolution distributions in $\PgUa\PgUa$ simulated
events and in events in data. The modeling of the signal process with a
resonance mass other than those for which simulated samples were generated
leads to a 2% uncertainty in the signal normalization for the resonance
search.

The discrete profiling method [39] is used to model the combinatorial
background. This allows the choice of the fit functions among those provided
to be considered as a discrete nuisance parameter. The parameters of these fit
functions are freely floating.

The normalization of the $\PgUa\PgUa$ background in the resonance search is
extracted from the 2D unbinned fit to the invariant mass of the dimuon pairs
in the mass region. The uncertainty in the yield obtained from the fit is
considered as a log-normal uncertainty in the fit to the
$\widetilde{m}_{\mathrm{4}\Pgm}$ distribution. The
$\widetilde{m}_{\mathrm{4}\Pgm}$ distribution of the $\PgUa\PgUa$ background
is allowed to float between the predictions for the SPS and DPS simulations.

Uncertainties in the $\widetilde{m}_{\mathrm{4}\Pgm}$ distribution of the
resonant signal take into account the limited size of the simulated samples,
and the limited precision of the description of the signal for masses not
available in simulations. The uncertainty in the mean mass of the signal is
0.2%, corresponding to the uncertainty in the muon momentum scale. The other
parameters describing the shape of the signal have an uncertainty between 5
and 15%, which leads to a combined impact on the final upper limits of less
than 2%.

The uncertainty in the dimuon branching fraction is not considered, since the
limits are set on the product of the resonance production cross section and
its branching fraction to four muons via an intermediate resonance.

###  0.6.3 Results

The binned $\widetilde{m}_{\mathrm{4}\Pgm}$ distribution in the signal region
of the resonance search is shown in Fig. 7. The background and example signal
components are shown using their best-fit shapes and normalizations. Using the
number of $\PgUa\PgUa$ events observed in data as a reference, a resonance
with a mass around 19and having a similar production cross section and
branching fraction to four muons as the $\PgUa\PgUa$ production, would produce
about 100 events in our sample, given the similarity between the kinematic
distributions of both processes. No significant narrow excess of events is
observed above the background expectation. The largest excess is observed for
a resonance mass of 25.1, and has a local significance of 2.4 standard
deviations for the scalar signal hypothesis.

Figure 7: The $\widetilde{m}_{\mathrm{4}\Pgm}$ distribution from data and the
results of the fit in the resonance search. An example signal is shown for the
tetraquark model with a mass of 19, which has a significance of about one
standard deviation.

Upper limits on the product of the production cross section of a resonance and
the branching fraction to a final state of four muons via an intermediate
resonance are set at 95% confidence level (CL) using the modified frequentist
construction in the asymptotic approximation [40, 41, 42, 43, 44], separately
for each signal model. The upper limits are extracted using unbinned
distributions. The cross section is defined in the entire phase space without
fiducial requirements, and the branching fraction used is the product of the
branching fraction of the resonant state to a meson and two muons, and the
branching fraction of the meson to two muons. Masses between 17.5 and 19.5are
probed in the context of the tetraquark search, using the bottomonium model,
whereas the limits in the extended mass range 16.5–27are set for the generic
search, using the JHUGen models. The corresponding upper limits are given in
Fig. 8. They range between 5 and 380fb, depending on the mass and signal
model. The patterns in the limits are broader for the spin-2 signal than for
the scalar and pseudoscalar states because the signal is characterized by
softer and more forward muons, leading to a worse
$\widetilde{m}_{\mathrm{4}\Pgm}$ resolution.

Figure 8: Upper limits at 95% on the product of the cross section and
branching fraction for a tetraquark (upper left), scalar (upper right),
pseudoscalar (lower left), and spin-2 (lower right) states. The symbol
$\sigma$ denotes the production cross section of the resonance, and the symbol
$\mathcal{B}$ denotes the product of the branching fraction for the decay of
the resonance to a $\PgUa$ meson and two muons, and the $\PgUa$ meson dimuon
branching fraction. The line with the points on it shows the observed upper
limits and the thin red line is the median of the expected upper limits. The
inner (green) band and the outer (yellow) band indicate the regions containing
68 and 95%, respectively, of the distribution of limits expected under the
background-only hypothesis.

##  0.7 Summary

The cross section for pair production is measured in the fiducial region where
both mesons have an absolute rapidity below 2.0. The measurement is performed
using proton-proton collision data collected at a center-of-mass energy of
13by the CMS detector in 2016 and corresponding to an integrated luminosity of
35.9. Assuming that the mesons are produced unpolarized, the fiducial pair
production cross section is determined to be $79\pm 11\stat\pm 6\syst\pm
3(\mathcal{B})$pb, where the last uncertainty comes from the uncertainty in
the dimuon branching fraction. The result can change if the mesons are
produced with a nonzero polarization. Changing the polarization coefficient
$\lambda_{\theta}$ from $-1$ to $+1$, the resulting pair production cross
section measurement varies by $-60$ to $+25\%$.

The contribution of double-parton scattering to the total inclusive pair
production cross section is determined for the first time. It is measured to
be ($39\pm 14$)% in the same fiducial region as described above, where the
uncertainty includes both statistical and systematic components, with the
statistical uncertainty dominating.

The results of a search are also presented for a light narrow resonance, such
as a tetraquark or a bound state beyond-the-standard model, decaying to a and
a pair of opposite-sign muons. No excess of events compatible with a signal is
observed in the four-muon invariant mass spectrum. Upper limits at 95%
confidence level on the product of the signal cross section and branching
fraction to four muons via an intermediate resonance are set for different
signal models, expanding the kinematic and mass coverage of previous searches.

###### Acknowledgements.

We congratulate our colleagues in the CERN accelerator departments for the
excellent performance of the LHC and thank the technical and administrative
staffs at CERN and at other CMS institutes for their contributions to the
success of the CMS effort. In addition, we gratefully acknowledge the
computing centers and personnel of the Worldwide LHC Computing Grid for
delivering so effectively the computing infrastructure essential to our
analyses. Finally, we acknowledge the enduring support for the construction
and operation of the LHC and the CMS detector provided by the following
funding agencies: BMBWF and FWF (Austria); FNRS and FWO (Belgium); CNPq,
CAPES, FAPERJ, FAPERGS, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST,
and NSFC (China); COLCIENCIAS (Colombia); MSES and CSF (Croatia); RPF
(Cyprus); SENESCYT (Ecuador); MoER, ERC IUT, PUT and ERDF (Estonia); Academy
of Finland, MEC, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG,
and HGF (Germany); GSRT (Greece); NKFIA (Hungary); DAE and DST (India); IPM
(Iran); SFI (Ireland); INFN (Italy); MSIP and NRF (Republic of Korea); MES
(Latvia); LAS (Lithuania); MOE and UM (Malaysia); BUAP, CINVESTAV, CONACYT,
LNS, SEP, and UASLP-FAI (Mexico); MOS (Montenegro); MBIE (New Zealand); PAEC
(Pakistan); MSHE and NSC (Poland); FCT (Portugal); JINR (Dubna); MON, RosAtom,
RAS, RFBR, and NRC KI (Russia); MESTD (Serbia); SEIDI, CPAN, PCTI, and FEDER
(Spain); MOSTR (Sri Lanka); Swiss Funding Agencies (Switzerland); MST
(Taipei); ThEPCenter, IPST, STAR, and NSTDA (Thailand); TUBITAK and TAEK
(Turkey); NASU (Ukraine); STFC (United Kingdom); DOE and NSF (USA).
Individuals have received support from the Marie-Curie program and the
European Research Council and Horizon 2020 Grant, contract Nos. 675440,
752730, and 765710 (European Union); the Leventis Foundation; the A.P. Sloan
Foundation; the Alexander von Humboldt Foundation; the Belgian Federal Science
Policy Office; the Fonds pour la Formation à la Recherche dans l’Industrie et
dans l’Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door
Wetenschap en Technologie (IWT-Belgium); the F.R.S.-FNRS and FWO (Belgium)
under the “Excellence of Science – EOS” – be.h project n. 30820817; the
Beijing Municipal Science & Technology Commission, No. Z191100007219010; the
Ministry of Education, Youth and Sports (MEYS) of the Czech Republic; the
Deutsche Forschungsgemeinschaft (DFG) under Germany’s Excellence Strategy –
EXC 2121 “Quantum Universe” – 390833306; the Lendület (“Momentum”) Program and
the János Bolyai Research Scholarship of the Hungarian Academy of Sciences,
the New National Excellence Program ÚNKP, the NKFIA research grants 123842,
123959, 124845, 124850, 125105, 128713, 128786, and 129058 (Hungary); the
Council of Science and Industrial Research, India; the HOMING PLUS program of
the Foundation for Polish Science, cofinanced from European Union, Regional
Development Fund, the Mobility Plus program of the Ministry of Science and
Higher Education, the National Science Center (Poland), contracts Harmonia
2014/14/M/ST2/00428, Opus 2014/13/B/ST2/02543, 2014/15/B/ST2/03998, and
2015/19/B/ST2/02861, Sonata-bis 2012/07/E/ST2/01406; the National Priorities
Research Program by Qatar National Research Fund; the Ministry of Science and
Education, grant no. 14.W03.31.0026 (Russia); the Programa Estatal de Fomento
de la Investigación Científica y Técnica de Excelencia María de Maeztu, grant
MDM-2015-0509 and the Programa Severo Ochoa del Principado de Asturias; the
Thalis and Aristeia programs cofinanced by EU-ESF and the Greek NSRF; the
Rachadapisek Sompot Fund for Postdoctoral Fellowship, Chulalongkorn University
and the Chulalongkorn Academic into Its 2nd Century Project Advancement
Project (Thailand); the Kavli Foundation; the Nvidia Corporation; the
SuperMicro Corporation; the Welch Foundation, contract C-1845; and the Weston
Havens Foundation (USA).

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##  .8 The CMS Collaboration

Yerevan Physics Institute, Yerevan, Armenia
A.M. Sirunyan${}^{\textrm{\textdagger}}$, A. Tumasyan Institut für
Hochenergiephysik, Wien, Austria
W. Adam, F. Ambrogi, T. Bergauer, M. Dragicevic, J. Erö, A. Escalante Del
Valle, M. Flechl, R. Frühwirth1, M. Jeitler1, N. Krammer, I. Krätschmer, D.
Liko, T. Madlener, I. Mikulec, N. Rad, J. Schieck1, R. Schöfbeck, M. Spanring,
W. Waltenberger, C.-E. Wulz1, M. Zarucki Institute for Nuclear Problems,
Minsk, Belarus
V. Drugakov, V. Mossolov, J. Suarez Gonzalez Universiteit Antwerpen,
Antwerpen, Belgium
M.R. Darwish, E.A. De Wolf, D. Di Croce, X. Janssen, A. Lelek, M. Pieters, H.
Rejeb Sfar, H. Van Haevermaet, P. Van Mechelen, S. Van Putte, N. Van Remortel
Vrije Universiteit Brussel, Brussel, Belgium
F. Blekman, E.S. Bols, S.S. Chhibra, J. D’Hondt, J. De Clercq, D. Lontkovskyi,
S. Lowette, I. Marchesini, S. Moortgat, Q. Python, S. Tavernier, W. Van
Doninck, P. Van Mulders Université Libre de Bruxelles, Bruxelles, Belgium
D. Beghin, B. Bilin, B. Clerbaux, G. De Lentdecker, H. Delannoy, B. Dorney, L.
Favart, A. Grebenyuk, A.K. Kalsi, L. Moureaux, A. Popov, N. Postiau, E.
Starling, L. Thomas, C. Vander Velde, P. Vanlaer, D. Vannerom Ghent
University, Ghent, Belgium
T. Cornelis, D. Dobur, I. Khvastunov2, M. Niedziela, C. Roskas, K. Skovpen, M.
Tytgat, W. Verbeke, B. Vermassen, M. Vit Université Catholique de Louvain,
Louvain-la-Neuve, Belgium
O. Bondu, G. Bruno, C. Caputo, P. David, C. Delaere, M. Delcourt, A.
Giammanco, V. Lemaitre, J. Prisciandaro, A. Saggio, M. Vidal Marono, P.
Vischia, J. Zobec Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro,
Brazil
G.A. Alves, G. Correia Silva, C. Hensel, A. Moraes Universidade do Estado do
Rio de Janeiro, Rio de Janeiro, Brazil
E. Belchior Batista Das Chagas, W. Carvalho, J. Chinellato3, E. Coelho, E.M.
Da Costa, G.G. Da Silveira4, D. De Jesus Damiao, C. De Oliveira Martins, S.
Fonseca De Souza, H. Malbouisson, J. Martins5, D. Matos Figueiredo, M. Medina
Jaime6, M. Melo De Almeida, C. Mora Herrera, L. Mundim, H. Nogima, W.L. Prado
Da Silva, P. Rebello Teles, L.J. Sanchez Rosas, A. Santoro, A. Sznajder, M.
Thiel, E.J. Tonelli Manganote3, F. Torres Da Silva De Araujo, A. Vilela
Pereira Universidade Estadual Paulista a, Universidade Federal do ABC b, São
Paulo, Brazil
C.A. Bernardesa, L. Calligarisa, T.R. Fernandez Perez Tomeia, E.M. Gregoresb,
D.S. Lemos, P.G. Mercadanteb, S.F. Novaesa, SandraS. Padulaa Institute for
Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia,
Bulgaria
A. Aleksandrov, G. Antchev, R. Hadjiiska, P. Iaydjiev, M. Misheva, M. Rodozov,
M. Shopova, G. Sultanov University of Sofia, Sofia, Bulgaria
M. Bonchev, A. Dimitrov, T. Ivanov, L. Litov, B. Pavlov, P. Petkov, A. Petrov
Beihang University, Beijing, China
W. Fang7, X. Gao7, L. Yuan Department of Physics, Tsinghua University,
Beijing, China
M. Ahmad, Z. Hu, Y. Wang Institute of High Energy Physics, Beijing, China
G.M. Chen8, H.S. Chen8, M. Chen, C.H. Jiang, D. Leggat, H. Liao, Z. Liu, A.
Spiezia, J. Tao, E. Yazgan, H. Zhang, S. Zhang8, J. Zhao State Key Laboratory
of Nuclear Physics and Technology, Peking University, Beijing, China
A. Agapitos, Y. Ban, G. Chen, A. Levin, J. Li, L. Li, Q. Li, Y. Mao, S.J.
Qian, D. Wang, Q. Wang Zhejiang University, Hangzhou, China
M. Xiao Universidad de Los Andes, Bogota, Colombia
C. Avila, A. Cabrera, C. Florez, C.F. González Hernández, M.A. Segura Delgado
Universidad de Antioquia, Medellin, Colombia
J. Mejia Guisao, J.D. Ruiz Alvarez, C.A. Salazar González, N. Vanegas Arbelaez
University of Split, Faculty of Electrical Engineering, Mechanical Engineering
and Naval Architecture, Split, Croatia
D. Giljanović, N. Godinovic, D. Lelas, I. Puljak, T. Sculac University of
Split, Faculty of Science, Split, Croatia
Z. Antunovic, M. Kovac Institute Rudjer Boskovic, Zagreb, Croatia
V. Brigljevic, D. Ferencek, K. Kadija, B. Mesic, M. Roguljic, A. Starodumov9,
T. Susa University of Cyprus, Nicosia, Cyprus
M.W. Ather, A. Attikis, E. Erodotou, A. Ioannou, M. Kolosova, S. Konstantinou,
G. Mavromanolakis, J. Mousa, C. Nicolaou, F. Ptochos, P.A. Razis, H.
Rykaczewski, H. Saka, D. Tsiakkouri Charles University, Prague, Czech Republic
M. Finger10, M. Finger Jr.10, A. Kveton, J. Tomsa Escuela Politecnica
Nacional, Quito, Ecuador
E. Ayala Universidad San Francisco de Quito, Quito, Ecuador
E. Carrera Jarrin Academy of Scientific Research and Technology of the Arab
Republic of Egypt, Egyptian Network of High Energy Physics, Cairo, Egypt
Y. Assran11,12, S. Elgammal12 National Institute of Chemical Physics and
Biophysics, Tallinn, Estonia
S. Bhowmik, A. Carvalho Antunes De Oliveira, R.K. Dewanjee, K. Ehataht, M.
Kadastik, M. Raidal, C. Veelken Department of Physics, University of Helsinki,
Helsinki, Finland
P. Eerola, L. Forthomme, H. Kirschenmann, K. Osterberg, M. Voutilainen
Helsinki Institute of Physics, Helsinki, Finland
F. Garcia, J. Havukainen, J.K. Heikkilä, V. Karimäki, M.S. Kim, R. Kinnunen,
T. Lampén, K. Lassila-Perini, S. Laurila, S. Lehti, T. Lindén, H. Siikonen, E.
Tuominen, J. Tuominiemi Lappeenranta University of Technology, Lappeenranta,
Finland
P. Luukka, T. Tuuva IRFU, CEA, Université Paris-Saclay, Gif-sur-Yvette, France
M. Besancon, F. Couderc, M. Dejardin, D. Denegri, B. Fabbro, J.L. Faure, F.
Ferri, S. Ganjour, A. Givernaud, P. Gras, G. Hamel de Monchenault, P. Jarry,
C. Leloup, B. Lenzi, E. Locci, J. Malcles, J. Rander, A. Rosowsky, M.Ö. Sahin,
A. Savoy-Navarro13, M. Titov, G.B. Yu Laboratoire Leprince-Ringuet,
CNRS/IN2P3, Ecole Polytechnique, Institut Polytechnique de Paris
S. Ahuja, C. Amendola, F. Beaudette, M. Bonanomi, P. Busson, C. Charlot, B.
Diab, G. Falmagne, R. Granier de Cassagnac, I. Kucher, A. Lobanov, C. Martin
Perez, M. Nguyen, C. Ochando, P. Paganini, J. Rembser, R. Salerno, J.B.
Sauvan, Y. Sirois, A. Zabi, A. Zghiche Université de Strasbourg, CNRS, IPHC
UMR 7178, Strasbourg, France
J.-L. Agram14, J. Andrea, D. Bloch, G. Bourgatte, J.-M. Brom, E.C. Chabert, C.
Collard, E. Conte14, J.-C. Fontaine14, D. Gelé, U. Goerlach, C. Grimault, M.
Jansová, A.-C. Le Bihan, N. Tonon, P. Van Hove Centre de Calcul de l’Institut
National de Physique Nucleaire et de Physique des Particules, CNRS/IN2P3,
Villeurbanne, France
S. Gadrat Université de Lyon, Université Claude Bernard Lyon 1, CNRS-IN2P3,
Institut de Physique Nucléaire de Lyon, Villeurbanne, France
S. Beauceron, C. Bernet, G. Boudoul, C. Camen, A. Carle, N. Chanon, R.
Chierici, D. Contardo, P. Depasse, H. El Mamouni, J. Fay, S. Gascon, M.
Gouzevitch, B. Ille, Sa. Jain, I.B. Laktineh, H. Lattaud, A. Lesauvage, M.
Lethuillier, L. Mirabito, S. Perries, V. Sordini, L. Torterotot, G. Touquet,
M. Vander Donckt, S. Viret Georgian Technical University, Tbilisi, Georgia
T. Toriashvili15 Tbilisi State University, Tbilisi, Georgia
Z. Tsamalaidze10 RWTH Aachen University, I. Physikalisches Institut, Aachen,
Germany
C. Autermann, L. Feld, K. Klein, M. Lipinski, D. Meuser, A. Pauls, M. Preuten,
M.P. Rauch, J. Schulz, M. Teroerde RWTH Aachen University, III. Physikalisches
Institut A, Aachen, Germany
M. Erdmann, B. Fischer, S. Ghosh, T. Hebbeker, K. Hoepfner, H. Keller, L.
Mastrolorenzo, M. Merschmeyer, A. Meyer, P. Millet, G. Mocellin, S. Mondal, S.
Mukherjee, D. Noll, A. Novak, T. Pook, A. Pozdnyakov, T. Quast, M. Radziej, Y.
Rath, H. Reithler, J. Roemer, A. Schmidt, S.C. Schuler, A. Sharma, S.
Wiedenbeck, S. Zaleski RWTH Aachen University, III. Physikalisches Institut B,
Aachen, Germany
G. Flügge, W. Haj Ahmad16, O. Hlushchenko, T. Kress, T. Müller, A. Nowack, C.
Pistone, O. Pooth, D. Roy, H. Sert, A. Stahl17 Deutsches Elektronen-
Synchrotron, Hamburg, Germany
M. Aldaya Martin, P. Asmuss, I. Babounikau, H. Bakhshiansohi, K. Beernaert, O.
Behnke, A. Bermúdez Martínez, A.A. Bin Anuar, K. Borras18, V. Botta, A.
Campbell, A. Cardini, P. Connor, S. Consuegra Rodríguez, C. Contreras-Campana,
V. Danilov, A. De Wit, M.M. Defranchis, C. Diez Pardos, D. Domínguez Damiani,
G. Eckerlin, D. Eckstein, T. Eichhorn, A. Elwood, E. Eren, E. Gallo19, A.
Geiser, A. Grohsjean, M. Guthoff, M. Haranko, A. Harb, A. Jafari, N.Z.
Jomhari, H. Jung, A. Kasem18, M. Kasemann, H. Kaveh, J. Keaveney, C.
Kleinwort, J. Knolle, D. Krücker, W. Lange, T. Lenz, J. Lidrych, K. Lipka, W.
Lohmann20, R. Mankel, I.-A. Melzer-Pellmann, A.B. Meyer, M. Meyer, M.
Missiroli, J. Mnich, A. Mussgiller, V. Myronenko, D. Pérez Adán, S.K.
Pflitsch, D. Pitzl, A. Raspereza, A. Saibel, M. Savitskyi, V. Scheurer, P.
Schütze, C. Schwanenberger, R. Shevchenko, A. Singh, R.E. Sosa Ricardo, H.
Tholen, O. Turkot, A. Vagnerini, M. Van De Klundert, R. Walsh, Y. Wen, K.
Wichmann, C. Wissing, O. Zenaiev, R. Zlebcik University of Hamburg, Hamburg,
Germany
R. Aggleton, S. Bein, L. Benato, A. Benecke, T. Dreyer, A. Ebrahimi, F.
Feindt, A. Fröhlich, C. Garbers, E. Garutti, D. Gonzalez, P. Gunnellini, J.
Haller, A. Hinzmann, A. Karavdina, G. Kasieczka, R. Klanner, R. Kogler, N.
Kovalchuk, S. Kurz, V. Kutzner, J. Lange, T. Lange, A. Malara, J. Multhaup,
C.E.N. Niemeyer, A. Reimers, O. Rieger, P. Schleper, S. Schumann, J. Schwandt,
J. Sonneveld, H. Stadie, G. Steinbrück, B. Vormwald, I. Zoi Karlsruher
Institut fuer Technologie, Karlsruhe, Germany
M. Akbiyik, M. Baselga, S. Baur, T. Berger, E. Butz, R. Caspart, T. Chwalek,
W. De Boer, A. Dierlamm, K. El Morabit, N. Faltermann, M. Giffels, A.
Gottmann, F. Hartmann17, C. Heidecker, U. Husemann, M.A. Iqbal, S. Kudella, S.
Maier, S. Mitra, M.U. Mozer, D. Müller, Th. Müller, M. Musich, A. Nürnberg, G.
Quast, K. Rabbertz, D. Schäfer, M. Schröder, I. Shvetsov, H.J. Simonis, R.
Ulrich, M. Wassmer, M. Weber, C. Wöhrmann, R. Wolf, S. Wozniewski Institute of
Nuclear and Particle Physics (INPP), NCSR Demokritos, Aghia Paraskevi, Greece
G. Anagnostou, P. Asenov, G. Daskalakis, T. Geralis, A. Kyriakis, D. Loukas,
G. Paspalaki, A. Stakia National and Kapodistrian University of Athens,
Athens, Greece
M. Diamantopoulou, G. Karathanasis, P. Kontaxakis, A. Manousakis-katsikakis,
A. Panagiotou, I. Papavergou, N. Saoulidou, K. Theofilatos, K. Vellidis, E.
Vourliotis National Technical University of Athens, Athens, Greece
G. Bakas, K. Kousouris, I. Papakrivopoulos, G. Tsipolitis, A. Zacharopoulou
University of Ioánnina, Ioánnina, Greece
I. Evangelou, C. Foudas, P. Gianneios, P. Katsoulis, P. Kokkas, S. Mallios, K.
Manitara, N. Manthos, I. Papadopoulos, J. Strologas, F.A. Triantis, D.
Tsitsonis MTA-ELTE Lendület CMS Particle and Nuclear Physics Group, Eötvös
Loránd University, Budapest, Hungary
M. Bartók21, R. Chudasama, M. Csanad, P. Major, K. Mandal, A. Mehta, G.
Pasztor, O. Surányi, G.I. Veres Wigner Research Centre for Physics, Budapest,
Hungary
G. Bencze, C. Hajdu, D. Horvath22, F. Sikler, V. Veszpremi, G.
Vesztergombi${}^{\textrm{\textdagger}}$ Institute of Nuclear Research ATOMKI,
Debrecen, Hungary
N. Beni, S. Czellar, J. Karancsi21, J. Molnar, Z. Szillasi Institute of
Physics, University of Debrecen, Debrecen, Hungary
P. Raics, D. Teyssier, Z.L. Trocsanyi, B. Ujvari Eszterhazy Karoly University,
Karoly Robert Campus, Gyongyos, Hungary
T. Csorgo, W.J. Metzger, F. Nemes, T. Novak Indian Institute of Science
(IISc), Bangalore, India
S. Choudhury, J.R. Komaragiri, P.C. Tiwari National Institute of Science
Education and Research, HBNI, Bhubaneswar, India
S. Bahinipati24, C. Kar, G. Kole, P. Mal, V.K. Muraleedharan Nair Bindhu, A.
Nayak25, D.K. Sahoo24, S.K. Swain Panjab University, Chandigarh, India
S. Bansal, S.B. Beri, V. Bhatnagar, S. Chauhan, N. Dhingra26, R. Gupta, A.
Kaur, M. Kaur, S. Kaur, P. Kumari, M. Lohan, M. Meena, K. Sandeep, S. Sharma,
J.B. Singh, A.K. Virdi University of Delhi, Delhi, India
A. Bhardwaj, B.C. Choudhary, R.B. Garg, M. Gola, S. Keshri, Ashok Kumar, M.
Naimuddin, P. Priyanka, K. Ranjan, Aashaq Shah, R. Sharma Saha Institute of
Nuclear Physics, HBNI, Kolkata, India
R. Bhardwaj27, M. Bharti27, R. Bhattacharya, S. Bhattacharya, U. Bhawandeep27,
D. Bhowmik, S. Dutta, S. Ghosh, B. Gomber28, M. Maity29, K. Mondal, S. Nandan,
A. Purohit, P.K. Rout, G. Saha, S. Sarkar, M. Sharan, B. Singh27, S. Thakur27
Indian Institute of Technology Madras, Madras, India
P.K. Behera, S.C. Behera, P. Kalbhor, A. Muhammad, P.R. Pujahari, A. Sharma,
A.K. Sikdar Bhabha Atomic Research Centre, Mumbai, India
D. Dutta, V. Jha, D.K. Mishra, P.K. Netrakanti, L.M. Pant, P. Shukla Tata
Institute of Fundamental Research-A, Mumbai, India
T. Aziz, M.A. Bhat, S. Dugad, G.B. Mohanty, N. Sur, RavindraKumar Verma Tata
Institute of Fundamental Research-B, Mumbai, India
S. Banerjee, S. Bhattacharya, S. Chatterjee, P. Das, M. Guchait, S. Karmakar,
S. Kumar, G. Majumder, K. Mazumdar, N. Sahoo, S. Sawant Indian Institute of
Science Education and Research (IISER), Pune, India
S. Dube, B. Kansal, A. Kapoor, K. Kothekar, S. Pandey, A. Rane, A. Rastogi, S.
Sharma Institute for Research in Fundamental Sciences (IPM), Tehran, Iran
S. Chenarani, S.M. Etesami, M. Khakzad, M. Mohammadi Najafabadi, M. Naseri, F.
Rezaei Hosseinabadi University College Dublin, Dublin, Ireland
M. Felcini, M. Grunewald INFN Sezione di Bari a, Università di Bari b,
Politecnico di Bari c, Bari, Italy
M. Abbresciaa,b, R. Alya,b,30, C. Calabriaa,b, A. Colaleoa, D. Creanzaa,c, L.
Cristellaa,b, N. De Filippisa,c, M. De Palmaa,b, A. Di Florioa,b, W.
Elmetenaweea,b, L. Fiorea, A. Gelmia,b, G. Iasellia,c, M. Incea,b, S.
Lezkia,b, G. Maggia,c, M. Maggia, J.A. Merlina, G. Minielloa,b, S. Mya,b, S.
Nuzzoa,b, A. Pompilia,b, G. Pugliesea,c, R. Radognaa, A. Ranieria, G.
Selvaggia,b, L. Silvestrisa, F.M. Simonea,b, R. Vendittia, P. Verwilligena
INFN Sezione di Bologna a, Università di Bologna b, Bologna, Italy
G. Abbiendia, C. Battilanaa,b, D. Bonacorsia,b, L. Borgonovia,b, S. Braibant-
Giacomellia,b, R. Campaninia,b, P. Capiluppia,b, A. Castroa,b, F.R. Cavalloa,
C. Cioccaa, G. Codispotia,b, M. Cuffiania,b, G.M. Dallavallea, F. Fabbria, A.
Fanfania,b, E. Fontanesia,b, P. Giacomellia, C. Grandia, L. Guiduccia,b, F.
Iemmia,b, S. Lo Meoa,31, S. Marcellinia, G. Masettia, F.L. Navarriaa,b, A.
Perrottaa, F. Primaveraa,b, A.M. Rossia,b, T. Rovellia,b, G.P. Sirolia,b, N.
Tosia INFN Sezione di Catania a, Università di Catania b, Catania, Italy
S. Albergoa,b,32, S. Costaa,b, A. Di Mattiaa, R. Potenzaa,b, A. Tricomia,b,32,
C. Tuvea,b INFN Sezione di Firenze a, Università di Firenze b, Firenze, Italy
G. Barbaglia, A. Cassese, R. Ceccarelli, V. Ciullia,b, C. Civininia, R.
D’Alessandroa,b, F. Fioria,c, E. Focardia,b, G. Latinoa,b, P. Lenzia,b, M.
Meschinia, S. Paolettia, G. Sguazzonia, L. Viliania INFN Laboratori Nazionali
di Frascati, Frascati, Italy
L. Benussi, S. Bianco, D. Piccolo INFN Sezione di Genova a, Università di
Genova b, Genova, Italy
M. Bozzoa,b, F. Ferroa, R. Mulargiaa,b, E. Robuttia, S. Tosia,b INFN Sezione
di Milano-Bicocca a, Università di Milano-Bicocca b, Milano, Italy
A. Benagliaa, A. Beschia,b, F. Brivioa,b, V. Cirioloa,b,17, M.E. Dinardoa,b,
P. Dinia, S. Gennaia, A. Ghezzia,b, P. Govonia,b, L. Guzzia,b, M. Malbertia,
S. Malvezzia, D. Menascea, F. Montia,b, L. Moronia, M. Paganonia,b, D.
Pedrinia, S. Ragazzia,b, T. Tabarelli de Fatisa,b, D. Valsecchia,b,17, D.
Zuoloa,b INFN Sezione di Napoli a, Università di Napoli ’Federico II’ b,
Napoli, Italy, Università della Basilicata c, Potenza, Italy, Università G.
Marconi d, Roma, Italy
S. Buontempoa, N. Cavalloa,c, A. De Iorioa,b, A. Di Crescenzoa,b, F.
Fabozzia,c, F. Fiengaa, G. Galatia, A.O.M. Iorioa,b, L. Layera,b, L. Listaa,b,
S. Meolaa,d,17, P. Paoluccia,17, B. Rossia, C. Sciaccaa,b, E. Voevodinaa,b
INFN Sezione di Padova a, Università di Padova b, Padova, Italy, Università di
Trento c, Trento, Italy
P. Azzia, N. Bacchettaa, D. Biselloa,b, A. Bolettia,b, A. Bragagnoloa,b, R.
Carlina,b, P. Checchiaa, P. De Castro Manzanoa, T. Dorigoa, U. Dossellia, F.
Gasparinia,b, U. Gasparinia,b, A. Gozzelinoa, S.Y. Hoha,b, M. Margonia,b, A.T.
Meneguzzoa,b, J. Pazzinia,b, M. Presillab, P. Ronchesea,b, R. Rossina,b, F.
Simonettoa,b, A. Tikoa, M. Tosia,b, M. Zanettia,b, P. Zottoa,b, A.
Zucchettaa,b, G. Zumerlea,b INFN Sezione di Pavia a, Università di Pavia b,
Pavia, Italy
A. Braghieria, D. Fiorinaa,b, P. Montagnaa,b, S.P. Rattia,b, V. Rea, M.
Ressegottia,b, C. Riccardia,b, P. Salvinia, I. Vaia, P. Vituloa,b INFN Sezione
di Perugia a, Università di Perugia b, Perugia, Italy
M. Biasinia,b, G.M. Bileia, D. Ciangottinia,b, L. Fanòa,b, P. Laricciaa,b, R.
Leonardia,b, E. Manonia, G. Mantovania,b, V. Mariania,b, M. Menichellia, A.
Rossia,b, A. Santocchiaa,b, D. Spigaa INFN Sezione di Pisa a, Università di
Pisa b, Scuola Normale Superiore di Pisa c, Pisa, Italy
K. Androsova, P. Azzurria, G. Bagliesia, V. Bertacchia,c, L. Bianchinia, T.
Boccalia, R. Castaldia, M.A. Cioccia,b, R. Dell’Orsoa, S. Donatoa, L.
Gianninia,c, A. Giassia, M.T. Grippoa, F. Ligabuea,c, E. Mancaa,c, G.
Mandorlia,c, A. Messineoa,b, F. Pallaa, A. Rizzia,b, G. Rolandia,c, S. Roy
Chowdhurya,c, A. Scribanoa, P. Spagnoloa, R. Tenchinia, G. Tonellia,b, N.
Turini, A. Venturia, P.G. Verdinia INFN Sezione di Roma a, Sapienza Università
di Roma b, Rome, Italy
F. Cavallaria, M. Cipriania,b, D. Del Rea,b, E. Di Marcoa, M. Diemoza, E.
Longoa,b, P. Meridiania, G. Organtinia,b, F. Pandolfia, R. Paramattia,b, C.
Quarantaa,b, S. Rahatloua,b, C. Rovellia, F. Santanastasioa,b, L. Soffia,b, R.
Tramontanoa,b INFN Sezione di Torino a, Università di Torino b, Torino, Italy,
Università del Piemonte Orientale c, Novara, Italy
N. Amapanea,b, R. Arcidiaconoa,c, S. Argiroa,b, M. Arneodoa,c, N. Bartosika,
R. Bellana,b, A. Belloraa,b, C. Biinoa, A. Cappatia,b, N. Cartigliaa, S.
Comettia, M. Costaa,b, R. Covarellia,b, N. Demariaa, J.R. González Fernándeza,
B. Kiania,b, F. Leggera, C. Mariottia, S. Masellia, E. Migliorea,b, V.
Monacoa,b, E. Monteila,b, M. Montenoa, M.M. Obertinoa,b, G. Ortonaa, L.
Pachera,b, N. Pastronea, M. Pelliccionia, G.L. Pinna Angionia,b, A. Romeroa,b,
M. Ruspaa,c, R. Salvaticoa,b, V. Solaa, A. Solanoa,b, D. Soldia,b, A.
Staianoa, D. Trocinoa,b INFN Sezione di Trieste a, Università di Trieste b,
Trieste, Italy
S. Belfortea, V. Candelisea,b, M. Casarsaa, F. Cossuttia, A. Da Rolda,b, G.
Della Riccaa,b, F. Vazzolera,b, A. Zanettia Kyungpook National University,
Daegu, Korea
B. Kim, D.H. Kim, G.N. Kim, J. Lee, S.W. Lee, C.S. Moon, Y.D. Oh, S.I. Pak, S.
Sekmen, D.C. Son, Y.C. Yang Chonnam National University, Institute for
Universe and Elementary Particles, Kwangju, Korea
H. Kim, D.H. Moon Hanyang University, Seoul, Korea
B. Francois, T.J. Kim, J. Park Korea University, Seoul, Korea
S. Cho, S. Choi, Y. Go, S. Ha, B. Hong, K. Lee, K.S. Lee, J. Lim, J. Park,
S.K. Park, Y. Roh, J. Yoo Kyung Hee University, Department of Physics
J. Goh Sejong University, Seoul, Korea
H.S. Kim Seoul National University, Seoul, Korea
J. Almond, J.H. Bhyun, J. Choi, S. Jeon, J. Kim, J.S. Kim, H. Lee, K. Lee, S.
Lee, K. Nam, M. Oh, S.B. Oh, B.C. Radburn-Smith, U.K. Yang, H.D. Yoo, I. Yoon
University of Seoul, Seoul, Korea
D. Jeon, J.H. Kim, J.S.H. Lee, I.C. Park, I.J Watson Sungkyunkwan University,
Suwon, Korea
Y. Choi, C. Hwang, Y. Jeong, J. Lee, Y. Lee, I. Yu Riga Technical University,
Riga, Latvia
V. Veckalns33 Vilnius University, Vilnius, Lithuania
V. Dudenas, A. Juodagalvis, A. Rinkevicius, G. Tamulaitis, J. Vaitkus National
Centre for Particle Physics, Universiti Malaya, Kuala Lumpur, Malaysia
F. Mohamad Idris34, W.A.T. Wan Abdullah, M.N. Yusli, Z. Zolkapli Universidad
de Sonora (UNISON), Hermosillo, Mexico
J.F. Benitez, A. Castaneda Hernandez, J.A. Murillo Quijada, L. Valencia Palomo
Centro de Investigacion y de Estudios Avanzados del IPN, Mexico City, Mexico
H. Castilla-Valdez, E. De La Cruz-Burelo, I. Heredia-De La Cruz35, R. Lopez-
Fernandez, A. Sanchez-Hernandez Universidad Iberoamericana, Mexico City,
Mexico
S. Carrillo Moreno, C. Oropeza Barrera, M. Ramirez-Garcia, F. Vazquez Valencia
Benemerita Universidad Autonoma de Puebla, Puebla, Mexico
J. Eysermans, I. Pedraza, H.A. Salazar Ibarguen, C. Uribe Estrada Universidad
Autónoma de San Luis Potosí, San Luis Potosí, Mexico
A. Morelos Pineda University of Montenegro, Podgorica, Montenegro
J. Mijuskovic2, N. Raicevic University of Auckland, Auckland, New Zealand
D. Krofcheck University of Canterbury, Christchurch, New Zealand
S. Bheesette, P.H. Butler, P. Lujan National Centre for Physics, Quaid-I-Azam
University, Islamabad, Pakistan
A. Ahmad, M. Ahmad, M.I.M. Awan, Q. Hassan, H.R. Hoorani, W.A. Khan, M.A.
Shah, M. Shoaib, M. Waqas AGH University of Science and Technology Faculty of
Computer Science, Electronics and Telecommunications, Krakow, Poland
V. Avati, L. Grzanka, M. Malawski National Centre for Nuclear Research,
Swierk, Poland
H. Bialkowska, M. Bluj, B. Boimska, M. Górski, M. Kazana, M. Szleper, P.
Zalewski Institute of Experimental Physics, Faculty of Physics, University of
Warsaw, Warsaw, Poland
K. Bunkowski, A. Byszuk36, K. Doroba, A. Kalinowski, M. Konecki, J.
Krolikowski, M. Olszewski, M. Walczak Laboratório de Instrumentação e Física
Experimental de Partículas, Lisboa, Portugal
M. Araujo, P. Bargassa, D. Bastos, A. Di Francesco, P. Faccioli, B. Galinhas,
M. Gallinaro, J. Hollar, N. Leonardo, T. Niknejad, J. Seixas, K. Shchelina, G.
Strong, O. Toldaiev, J. Varela Joint Institute for Nuclear Research, Dubna,
Russia
S. Afanasiev, P. Bunin, M. Gavrilenko, I. Golutvin, I. Gorbunov, A. Kamenev,
V. Karjavine, A. Lanev, A. Malakhov, V. Matveev37,38, P. Moisenz, V. Palichik,
V. Perelygin, M. Savina, S. Shmatov, S. Shulha, N. Skatchkov, V. Smirnov, N.
Voytishin, A. Zarubin Petersburg Nuclear Physics Institute, Gatchina (St.
Petersburg), Russia
L. Chtchipounov, V. Golovtcov, Y. Ivanov, V. Kim39, E. Kuznetsova40, P.
Levchenko, V. Murzin, V. Oreshkin, I. Smirnov, D. Sosnov, V. Sulimov, L.
Uvarov, A. Vorobyev Institute for Nuclear Research, Moscow, Russia
Yu. Andreev, A. Dermenev, S. Gninenko, N. Golubev, A. Karneyeu, M. Kirsanov,
N. Krasnikov, A. Pashenkov, D. Tlisov, A. Toropin Institute for Theoretical
and Experimental Physics named by A.I. Alikhanov of NRC ‘Kurchatov Institute’,
Moscow, Russia
V. Epshteyn, V. Gavrilov, N. Lychkovskaya, A. Nikitenko41, V. Popov, I.
Pozdnyakov, G. Safronov, A. Spiridonov, A. Stepennov, M. Toms, E. Vlasov, A.
Zhokin Moscow Institute of Physics and Technology, Moscow, Russia
T. Aushev National Research Nuclear University ’Moscow Engineering Physics
Institute’ (MEPhI), Moscow, Russia
O. Bychkova, R. Chistov42, M. Danilov42, S. Polikarpov42, E. Tarkovskii P.N.
Lebedev Physical Institute, Moscow, Russia
V. Andreev, M. Azarkin, I. Dremin, M. Kirakosyan, A. Terkulov Skobeltsyn
Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow,
Russia
A. Belyaev, E. Boos, M. Dubinin43, L. Dudko, A. Ershov, A. Gribushin, V.
Klyukhin, O. Kodolova, I. Lokhtin, S. Obraztsov, S. Petrushanko, V. Savrin, A.
Snigirev Novosibirsk State University (NSU), Novosibirsk, Russia
A. Barnyakov44, V. Blinov44, T. Dimova44, L. Kardapoltsev44, Y. Skovpen44
Institute for High Energy Physics of National Research Centre ‘Kurchatov
Institute’, Protvino, Russia
I. Azhgirey, I. Bayshev, S. Bitioukov, V. Kachanov, D. Konstantinov, P.
Mandrik, V. Petrov, R. Ryutin, S. Slabospitskii, A. Sobol, S. Troshin, N.
Tyurin, A. Uzunian, A. Volkov National Research Tomsk Polytechnic University,
Tomsk, Russia
A. Babaev, A. Iuzhakov, V. Okhotnikov Tomsk State University, Tomsk, Russia
V. Borchsh, V. Ivanchenko, E. Tcherniaev University of Belgrade: Faculty of
Physics and VINCA Institute of Nuclear Sciences
P. Adzic45, P. Cirkovic, M. Dordevic, P. Milenovic, J. Milosevic, M.
Stojanovic Centro de Investigaciones Energéticas Medioambientales y
Tecnológicas (CIEMAT), Madrid, Spain
M. Aguilar-Benitez, J. Alcaraz Maestre, A. Álvarez Fernández, I. Bachiller, M.
Barrio Luna, CristinaF. Bedoya, J.A. Brochero Cifuentes, C.A. Carrillo
Montoya, M. Cepeda, M. Cerrada, N. Colino, B. De La Cruz, A. Delgado Peris,
J.P. Fernández Ramos, J. Flix, M.C. Fouz, O. Gonzalez Lopez, S. Goy Lopez,
J.M. Hernandez, M.I. Josa, D. Moran, Á. Navarro Tobar, A. Pérez-Calero
Yzquierdo, J. Puerta Pelayo, I. Redondo, L. Romero, S. Sánchez Navas, M.S.
Soares, A. Triossi, C. Willmott Universidad Autónoma de Madrid, Madrid, Spain
C. Albajar, J.F. de Trocóniz, R. Reyes-Almanza Universidad de Oviedo,
Instituto Universitario de Ciencias y Tecnologías Espaciales de Asturias
(ICTEA), Oviedo, Spain
B. Alvarez Gonzalez, J. Cuevas, C. Erice, J. Fernandez Menendez, S. Folgueras,
I. Gonzalez Caballero, E. Palencia Cortezon, C. Ramón Álvarez, V. Rodríguez
Bouza, S. Sanchez Cruz Instituto de Física de Cantabria (IFCA), CSIC-
Universidad de Cantabria, Santander, Spain
I.J. Cabrillo, A. Calderon, B. Chazin Quero, J. Duarte Campderros, M.
Fernandez, P.J. Fernández Manteca, A. García Alonso, G. Gomez, C. Martinez
Rivero, P. Martinez Ruiz del Arbol, F. Matorras, J. Piedra Gomez, C. Prieels,
F. Ricci-Tam, T. Rodrigo, A. Ruiz-Jimeno, L. Russo46, L. Scodellaro, I. Vila,
J.M. Vizan Garcia University of Colombo, Colombo, Sri Lanka
D.U.J. Sonnadara University of Ruhuna, Department of Physics, Matara, Sri
Lanka
W.G.D. Dharmaratna, N. Wickramage CERN, European Organization for Nuclear
Research, Geneva, Switzerland
T.K. Aarrestad, D. Abbaneo, B. Akgun, E. Auffray, G. Auzinger, J. Baechler, P.
Baillon, A.H. Ball, D. Barney, J. Bendavid, M. Bianco, A. Bocci, P. Bortignon,
E. Bossini, E. Brondolin, T. Camporesi, A. Caratelli, G. Cerminara, E. Chapon,
G. Cucciati, D. d’Enterria, A. Dabrowski, N. Daci, V. Daponte, A. David, O.
Davignon, A. De Roeck, M. Deile, R. Di Maria, M. Dobson, M. Dünser, N. Dupont,
A. Elliott-Peisert, N. Emriskova, F. Fallavollita47, D. Fasanella, S.
Fiorendi, G. Franzoni, J. Fulcher, W. Funk, S. Giani, D. Gigi, K. Gill, F.
Glege, L. Gouskos, M. Gruchala, M. Guilbaud, D. Gulhan, J. Hegeman, C.
Heidegger, Y. Iiyama, V. Innocente, T. James, P. Janot, O. Karacheban20, J.
Kaspar, J. Kieseler, M. Krammer1, N. Kratochwil, C. Lange, P. Lecoq, K. Long,
C. Lourenço, L. Malgeri, M. Mannelli, A. Massironi, F. Meijers, S. Mersi, E.
Meschi, F. Moortgat, M. Mulders, J. Ngadiuba, J. Niedziela, S. Nourbakhsh, S.
Orfanelli, L. Orsini, F. Pantaleo17, L. Pape, E. Perez, M. Peruzzi, A.
Petrilli, G. Petrucciani, A. Pfeiffer, M. Pierini, F.M. Pitters, D. Rabady, A.
Racz, M. Rieger, M. Rovere, H. Sakulin, J. Salfeld-Nebgen, S. Scarfi, C.
Schäfer, C. Schwick, M. Selvaggi, A. Sharma, P. Silva, W. Snoeys, P.
Sphicas48, J. Steggemann, S. Summers, V.R. Tavolaro, D. Treille, A. Tsirou,
G.P. Van Onsem, A. Vartak, M. Verzetti, K.A. Wozniak, W.D. Zeuner Paul
Scherrer Institut, Villigen, Switzerland
L. Caminada49, K. Deiters, W. Erdmann, R. Horisberger, Q. Ingram, H.C.
Kaestli, D. Kotlinski, U. Langenegger, T. Rohe ETH Zurich - Institute for
Particle Physics and Astrophysics (IPA), Zurich, Switzerland
M. Backhaus, P. Berger, N. Chernyavskaya, G. Dissertori, M. Dittmar, M.
Donegà, C. Dorfer, T.A. Gómez Espinosa, C. Grab, D. Hits, W. Lustermann, R.A.
Manzoni, M.T. Meinhard, F. Micheli, P. Musella, F. Nessi-Tedaldi, F. Pauss, V.
Perovic, G. Perrin, L. Perrozzi, S. Pigazzini, M.G. Ratti, M. Reichmann, C.
Reissel, T. Reitenspiess, B. Ristic, D. Ruini, D.A. Sanz Becerra, M.
Schönenberger, L. Shchutska, M.L. Vesterbacka Olsson, R. Wallny, D.H. Zhu
Universität Zürich, Zurich, Switzerland
C. Amsler50, C. Botta, D. Brzhechko, M.F. Canelli, A. De Cosa, R. Del Burgo,
B. Kilminster, S. Leontsinis, V.M. Mikuni, I. Neutelings, G. Rauco, P.
Robmann, K. Schweiger, Y. Takahashi, S. Wertz National Central University,
Chung-Li, Taiwan
C.M. Kuo, W. Lin, A. Roy, T. Sarkar29, S.S. Yu National Taiwan University
(NTU), Taipei, Taiwan
P. Chang, Y. Chao, K.F. Chen, P.H. Chen, W.-S. Hou, Y.y. Li, R.-S. Lu, E.
Paganis, A. Psallidas, A. Steen Chulalongkorn University, Faculty of Science,
Department of Physics, Bangkok, Thailand
B. Asavapibhop, C. Asawatangtrakuldee, N. Srimanobhas, N. Suwonjandee Çukurova
University, Physics Department, Science and Art Faculty, Adana, Turkey
A. Bat, F. Boran, A. Celik51, S. Damarseckin52, Z.S. Demiroglu, F. Dolek, C.
Dozen53, I. Dumanoglu54, G. Gokbulut, EmineGurpinar Guler55, Y. Guler, I.
Hos56, C. Isik, E.E. Kangal57, O. Kara, A. Kayis Topaksu, U. Kiminsu, G.
Onengut, K. Ozdemir58, S. Ozturk59, A.E. Simsek, U.G. Tok, S. Turkcapar, I.S.
Zorbakir, C. Zorbilmez Middle East Technical University, Physics Department,
Ankara, Turkey
B. Isildak60, G. Karapinar61, M. Yalvac62 Bogazici University, Istanbul,
Turkey
I.O. Atakisi, E. Gülmez, M. Kaya63, O. Kaya64, Ö. Özçelik, S. Tekten64, E.A.
Yetkin65 Istanbul Technical University, Istanbul, Turkey
A. Cakir, K. Cankocak54, Y. Komurcu, S. Sen66 Istanbul University, Istanbul,
Turkey
S. Cerci67, B. Kaynak, S. Ozkorucuklu, D. Sunar Cerci67 Institute for
Scintillation Materials of National Academy of Science of Ukraine, Kharkov,
Ukraine
B. Grynyov National Scientific Center, Kharkov Institute of Physics and
Technology, Kharkov, Ukraine
L. Levchuk University of Bristol, Bristol, United Kingdom
E. Bhal, S. Bologna, J.J. Brooke, D. Burns68, E. Clement, D. Cussans, H.
Flacher, J. Goldstein, G.P. Heath, H.F. Heath, L. Kreczko, B. Krikler, S.
Paramesvaran, T. Sakuma, S. Seif El Nasr-Storey, V.J. Smith, J. Taylor, A.
Titterton Rutherford Appleton Laboratory, Didcot, United Kingdom
K.W. Bell, A. Belyaev69, C. Brew, R.M. Brown, D.J.A. Cockerill, J.A. Coughlan,
K. Harder, S. Harper, J. Linacre, K. Manolopoulos, D.M. Newbold, E. Olaiya, D.
Petyt, T. Reis, T. Schuh, C.H. Shepherd-Themistocleous, A. Thea, I.R. Tomalin,
T. Williams Imperial College, London, United Kingdom
R. Bainbridge, P. Bloch, S. Bonomally, J. Borg, S. Breeze, O. Buchmuller, A.
Bundock, GurpreetSingh CHAHAL70, D. Colling, P. Dauncey, G. Davies, M. Della
Negra, P. Everaerts, G. Hall, G. Iles, M. Komm, L. Lyons, A.-M. Magnan, S.
Malik, A. Martelli, V. Milosevic, A. Morton, J. Nash71, V. Palladino, M.
Pesaresi, D.M. Raymond, A. Richards, A. Rose, E. Scott, C. Seez, A.
Shtipliyski, M. Stoye, T. Strebler, A. Tapper, K. Uchida, T. Virdee17, N.
Wardle, S.N. Webb, D. Winterbottom, A.G. Zecchinelli, S.C. Zenz Brunel
University, Uxbridge, United Kingdom
J.E. Cole, P.R. Hobson, A. Khan, P. Kyberd, C.K. Mackay, I.D. Reid, L.
Teodorescu, S. Zahid Baylor University, Waco, USA
A. Brinkerhoff, K. Call, B. Caraway, J. Dittmann, K. Hatakeyama, C. Madrid, B.
McMaster, N. Pastika, C. Smith Catholic University of America, Washington, DC,
USA
R. Bartek, A. Dominguez, R. Uniyal, A.M. Vargas Hernandez The University of
Alabama, Tuscaloosa, USA
A. Buccilli, S.I. Cooper, S.V. Gleyzer, C. Henderson, P. Rumerio, C. West
Boston University, Boston, USA
A. Albert, D. Arcaro, Z. Demiragli, D. Gastler, C. Richardson, J. Rohlf, D.
Sperka, D. Spitzbart, I. Suarez, L. Sulak, D. Zou Brown University,
Providence, USA
G. Benelli, B. Burkle, X. Coubez18, D. Cutts, Y.t. Duh, M. Hadley, U. Heintz,
J.M. Hogan72, K.H.M. Kwok, E. Laird, G. Landsberg, K.T. Lau, J. Lee, M.
Narain, S. Sagir73, R. Syarif, E. Usai, W.Y. Wong, D. Yu, W. Zhang University
of California, Davis, Davis, USA
R. Band, C. Brainerd, R. Breedon, M. Calderon De La Barca Sanchez, M. Chertok,
J. Conway, R. Conway, P.T. Cox, R. Erbacher, C. Flores, G. Funk, F. Jensen, W.
Ko${}^{\textrm{\textdagger}}$, O. Kukral, R. Lander, M. Mulhearn, D. Pellett,
J. Pilot, M. Shi, D. Taylor, K. Tos, M. Tripathi, Z. Wang, F. Zhang University
of California, Los Angeles, USA
M. Bachtis, C. Bravo, R. Cousins, A. Dasgupta, A. Florent, J. Hauser, M.
Ignatenko, N. Mccoll, W.A. Nash, S. Regnard, D. Saltzberg, C. Schnaible, B.
Stone, V. Valuev University of California, Riverside, Riverside, USA
K. Burt, Y. Chen, R. Clare, J.W. Gary, S.M.A. Ghiasi Shirazi, G. Hanson, G.
Karapostoli, O.R. Long, N. Manganelli, M. Olmedo Negrete, M.I. Paneva, W. Si,
S. Wimpenny, B.R. Yates, Y. Zhang University of California, San Diego, La
Jolla, USA
J.G. Branson, P. Chang, S. Cittolin, S. Cooperstein, N. Deelen, M. Derdzinski,
J. Duarte, R. Gerosa, D. Gilbert, B. Hashemi, D. Klein, V. Krutelyov, J.
Letts, M. Masciovecchio, S. May, S. Padhi, M. Pieri, V. Sharma, M. Tadel, F.
Würthwein, A. Yagil, G. Zevi Della Porta University of California, Santa
Barbara - Department of Physics, Santa Barbara, USA
N. Amin, R. Bhandari, C. Campagnari, M. Citron, V. Dutta, J. Incandela, B.
Marsh, H. Mei, A. Ovcharova, H. Qu, J. Richman, U. Sarica, D. Stuart, S. Wang
California Institute of Technology, Pasadena, USA
D. Anderson, A. Bornheim, O. Cerri, I. Dutta, J.M. Lawhorn, N. Lu, J. Mao,
H.B. Newman, T.Q. Nguyen, J. Pata, M. Spiropulu, J.R. Vlimant, S. Xie, Z.
Zhang, R.Y. Zhu Carnegie Mellon University, Pittsburgh, USA
J. Alison, M.B. Andrews, T. Ferguson, T. Mudholkar, M. Paulini, M. Sun, I.
Vorobiev, M. Weinberg University of Colorado Boulder, Boulder, USA
J.P. Cumalat, W.T. Ford, E. MacDonald, T. Mulholland, R. Patel, A. Perloff, K.
Stenson, K.A. Ulmer, S.R. Wagner Cornell University, Ithaca, USA
J. Alexander, Y. Cheng, J. Chu, A. Datta, A. Frankenthal, K. Mcdermott, J.R.
Patterson, D. Quach, A. Ryd, S.M. Tan, Z. Tao, J. Thom, P. Wittich, M. Zientek
Fermi National Accelerator Laboratory, Batavia, USA
S. Abdullin, M. Albrow, M. Alyari, G. Apollinari, A. Apresyan, A. Apyan, S.
Banerjee, L.A.T. Bauerdick, A. Beretvas, D. Berry, J. Berryhill, P.C. Bhat, K.
Burkett, J.N. Butler, A. Canepa, G.B. Cerati, H.W.K. Cheung, F. Chlebana, M.
Cremonesi, V.D. Elvira, J. Freeman, Z. Gecse, E. Gottschalk, L. Gray, D.
Green, S. Grünendahl, O. Gutsche, J. Hanlon, R.M. Harris, S. Hasegawa, R.
Heller, J. Hirschauer, B. Jayatilaka, S. Jindariani, M. Johnson, U. Joshi, T.
Klijnsma, B. Klima, M.J. Kortelainen, B. Kreis, S. Lammel, J. Lewis, D.
Lincoln, R. Lipton, M. Liu, T. Liu, J. Lykken, K. Maeshima, J.M. Marraffino,
D. Mason, P. McBride, P. Merkel, S. Mrenna, S. Nahn, V. O’Dell, V.
Papadimitriou, K. Pedro, C. Pena43, F. Ravera, A. Reinsvold Hall, L. Ristori,
B. Schneider, E. Sexton-Kennedy, N. Smith, A. Soha, W.J. Spalding, L. Spiegel,
S. Stoynev, J. Strait, L. Taylor, S. Tkaczyk, N.V. Tran, L. Uplegger, E.W.
Vaandering, C. Vernieri, R. Vidal, M. Wang, H.A. Weber, A. Woodard University
of Florida, Gainesville, USA
D. Acosta, P. Avery, D. Bourilkov, L. Cadamuro, V. Cherepanov, F. Errico, R.D.
Field, D. Guerrero, B.M. Joshi, M. Kim, J. Konigsberg, A. Korytov, K.H. Lo, K.
Matchev, N. Menendez, G. Mitselmakher, D. Rosenzweig, K. Shi, J. Wang, S.
Wang, X. Zuo Florida International University, Miami, USA
Y.R. Joshi Florida State University, Tallahassee, USA
T. Adams, A. Askew, S. Hagopian, V. Hagopian, K.F. Johnson, R. Khurana, T.
Kolberg, G. Martinez, T. Perry, H. Prosper, C. Schiber, R. Yohay, J. Zhang
Florida Institute of Technology, Melbourne, USA
M.M. Baarmand, M. Hohlmann, D. Noonan, M. Rahmani, M. Saunders, F. Yumiceva
University of Illinois at Chicago (UIC), Chicago, USA
M.R. Adams, L. Apanasevich, R.R. Betts, R. Cavanaugh, X. Chen, S. Dittmer, O.
Evdokimov, C.E. Gerber, D.A. Hangal, D.J. Hofman, V. Kumar, C. Mills, G. Oh,
T. Roy, M.B. Tonjes, N. Varelas, J. Viinikainen, H. Wang, X. Wang, Z. Wu The
University of Iowa, Iowa City, USA
M. Alhusseini, B. Bilki55, K. Dilsiz74, S. Durgut, R.P. Gandrajula, M.
Haytmyradov, V. Khristenko, O.K. Köseyan, J.-P. Merlo, A. Mestvirishvili75, A.
Moeller, J. Nachtman, H. Ogul76, Y. Onel, F. Ozok77, A. Penzo, C. Snyder, E.
Tiras, J. Wetzel Johns Hopkins University, Baltimore, USA
B. Blumenfeld, A. Cocoros, N. Eminizer, A.V. Gritsan, W.T. Hung, S. Kyriacou,
P. Maksimovic, C. Mantilla, J. Roskes, M. Swartz, T.Á. Vámi The University of
Kansas, Lawrence, USA
C. Baldenegro Barrera, P. Baringer, A. Bean, S. Boren, A. Bylinkin, T.
Isidori, S. Khalil, J. King, G. Krintiras, A. Kropivnitskaya, C. Lindsey, D.
Majumder, W. Mcbrayer, N. Minafra, M. Murray, C. Rogan, C. Royon, S. Sanders,
E. Schmitz, J.D. Tapia Takaki, Q. Wang, J. Williams, G. Wilson Kansas State
University, Manhattan, USA
S. Duric, A. Ivanov, K. Kaadze, D. Kim, Y. Maravin, D.R. Mendis, T. Mitchell,
A. Modak, A. Mohammadi Lawrence Livermore National Laboratory, Livermore, USA
F. Rebassoo, D. Wright University of Maryland, College Park, USA
A. Baden, O. Baron, A. Belloni, S.C. Eno, Y. Feng, N.J. Hadley, S. Jabeen,
G.Y. Jeng, R.G. Kellogg, A.C. Mignerey, S. Nabili, M. Seidel, Y.H. Shin, A.
Skuja, S.C. Tonwar, L. Wang, K. Wong Massachusetts Institute of Technology,
Cambridge, USA
D. Abercrombie, B. Allen, R. Bi, S. Brandt, W. Busza, I.A. Cali, M. D’Alfonso,
G. Gomez Ceballos, M. Goncharov, P. Harris, D. Hsu, M. Hu, M. Klute, D.
Kovalskyi, Y.-J. Lee, P.D. Luckey, B. Maier, A.C. Marini, C. Mcginn, C.
Mironov, S. Narayanan, X. Niu, C. Paus, D. Rankin, C. Roland, G. Roland, Z.
Shi, G.S.F. Stephans, K. Sumorok, K. Tatar, D. Velicanu, J. Wang, T.W. Wang,
B. Wyslouch University of Minnesota, Minneapolis, USA
R.M. Chatterjee, A. Evans, S. Guts${}^{\textrm{\textdagger}}$, P. Hansen, J.
Hiltbrand, Sh. Jain, Y. Kubota, Z. Lesko, J. Mans, M. Revering, R. Rusack, R.
Saradhy, N. Schroeder, N. Strobbe, M.A. Wadud University of Mississippi,
Oxford, USA
J.G. Acosta, S. Oliveros University of Nebraska-Lincoln, Lincoln, USA
K. Bloom, S. Chauhan, D.R. Claes, C. Fangmeier, L. Finco, F. Golf, R.
Kamalieddin, I. Kravchenko, J.E. Siado, G.R. Snow${}^{\textrm{\textdagger}}$,
B. Stieger, W. Tabb State University of New York at Buffalo, Buffalo, USA
G. Agarwal, C. Harrington, I. Iashvili, A. Kharchilava, C. McLean, D. Nguyen,
A. Parker, J. Pekkanen, S. Rappoccio, B. Roozbahani Northeastern University,
Boston, USA
G. Alverson, E. Barberis, C. Freer, Y. Haddad, A. Hortiangtham, G. Madigan, B.
Marzocchi, D.M. Morse, T. Orimoto, L. Skinnari, A. Tishelman-Charny, T.
Wamorkar, B. Wang, A. Wisecarver, D. Wood Northwestern University, Evanston,
USA
S. Bhattacharya, J. Bueghly, G. Fedi, A. Gilbert, T. Gunter, K.A. Hahn, N.
Odell, M.H. Schmitt, K. Sung, M. Velasco University of Notre Dame, Notre Dame,
USA
R. Bucci, N. Dev, R. Goldouzian, M. Hildreth, K. Hurtado Anampa, C. Jessop,
D.J. Karmgard, K. Lannon, W. Li, N. Loukas, N. Marinelli, I. Mcalister, F.
Meng, Y. Musienko37, R. Ruchti, P. Siddireddy, G. Smith, S. Taroni, M. Wayne,
A. Wightman, M. Wolf The Ohio State University, Columbus, USA
J. Alimena, B. Bylsma, B. Cardwell, L.S. Durkin, B. Francis, C. Hill, W. Ji,
A. Lefeld, T.Y. Ling, B.L. Winer Princeton University, Princeton, USA
G. Dezoort, P. Elmer, J. Hardenbrook, N. Haubrich, S. Higginbotham, A.
Kalogeropoulos, S. Kwan, D. Lange, M.T. Lucchini, J. Luo, D. Marlow, K. Mei,
I. Ojalvo, J. Olsen, C. Palmer, P. Piroué, D. Stickland, C. Tully University
of Puerto Rico, Mayaguez, USA
S. Malik, S. Norberg Purdue University, West Lafayette, USA
A. Barker, V.E. Barnes, R. Chawla, S. Das, L. Gutay, M. Jones, A.W. Jung, B.
Mahakud, D.H. Miller, G. Negro, N. Neumeister, C.C. Peng, S. Piperov, H. Qiu,
J.F. Schulte, N. Trevisani, F. Wang, R. Xiao, W. Xie Purdue University
Northwest, Hammond, USA
T. Cheng, J. Dolen, N. Parashar Rice University, Houston, USA
A. Baty, U. Behrens, S. Dildick, K.M. Ecklund, S. Freed, F.J.M. Geurts, M.
Kilpatrick, Arun Kumar, W. Li, B.P. Padley, R. Redjimi, J. Roberts, J. Rorie,
W. Shi, A.G. Stahl Leiton, Z. Tu, A. Zhang University of Rochester, Rochester,
USA
A. Bodek, P. de Barbaro, R. Demina, J.L. Dulemba, C. Fallon, T. Ferbel, M.
Galanti, A. Garcia-Bellido, O. Hindrichs, A. Khukhunaishvili, E. Ranken, R.
Taus Rutgers, The State University of New Jersey, Piscataway, USA
B. Chiarito, J.P. Chou, A. Gandrakota, Y. Gershtein, E. Halkiadakis, A. Hart,
M. Heindl, E. Hughes, S. Kaplan, I. Laflotte, A. Lath, R. Montalvo, K. Nash,
M. Osherson, S. Salur, S. Schnetzer, S. Somalwar, R. Stone, S. Thomas
University of Tennessee, Knoxville, USA
H. Acharya, A.G. Delannoy, S. Spanier Texas A&M University, College Station,
USA
O. Bouhali78, M. Dalchenko, M. De Mattia, A. Delgado, R. Eusebi, J. Gilmore,
T. Huang, T. Kamon79, H. Kim, S. Luo, S. Malhotra, D. Marley, R. Mueller, D.
Overton, L. Perniè, D. Rathjens, A. Safonov Texas Tech University, Lubbock,
USA
N. Akchurin, J. Damgov, F. De Guio, V. Hegde, S. Kunori, K. Lamichhane, S.W.
Lee, T. Mengke, S. Muthumuni, T. Peltola, S. Undleeb, I. Volobouev, Z. Wang,
A. Whitbeck Vanderbilt University, Nashville, USA
S. Greene, A. Gurrola, R. Janjam, W. Johns, C. Maguire, A. Melo, H. Ni, K.
Padeken, F. Romeo, P. Sheldon, S. Tuo, J. Velkovska, M. Verweij University of
Virginia, Charlottesville, USA
M.W. Arenton, P. Barria, B. Cox, G. Cummings, J. Hakala, R. Hirosky, M. Joyce,
A. Ledovskoy, C. Neu, B. Tannenwald, Y. Wang, E. Wolfe, F. Xia Wayne State
University, Detroit, USA
R. Harr, P.E. Karchin, N. Poudyal, J. Sturdy, P. Thapa University of Wisconsin
- Madison, Madison, WI, USA
K. Black, T. Bose, J. Buchanan, C. Caillol, D. Carlsmith, S. Dasu, I. De
Bruyn, L. Dodd, C. Galloni, H. He, M. Herndon, A. Hervé, U. Hussain, A.
Lanaro, A. Loeliger, R. Loveless, J. Madhusudanan Sreekala, A. Mallampalli, D.
Pinna, T. Ruggles, A. Savin, V. Sharma, W.H. Smith, D. Teague, S. Trembath-
reichert †: Deceased
1: Also at Vienna University of Technology, Vienna, Austria
2: Also at IRFU, CEA, Université Paris-Saclay, Gif-sur-Yvette, France
3: Also at Universidade Estadual de Campinas, Campinas, Brazil
4: Also at Federal University of Rio Grande do Sul, Porto Alegre, Brazil
5: Also at UFMS, Nova Andradina, Brazil
6: Also at Universidade Federal de Pelotas, Pelotas, Brazil
7: Also at Université Libre de Bruxelles, Bruxelles, Belgium
8: Also at University of Chinese Academy of Sciences, Beijing, China
9: Also at Institute for Theoretical and Experimental Physics named by A.I.
Alikhanov of NRC ‘Kurchatov Institute’, Moscow, Russia
10: Also at Joint Institute for Nuclear Research, Dubna, Russia
11: Also at Suez University, Suez, Egypt
12: Now at British University in Egypt, Cairo, Egypt
13: Also at Purdue University, West Lafayette, USA
14: Also at Université de Haute Alsace, Mulhouse, France
15: Also at Tbilisi State University, Tbilisi, Georgia
16: Also at Erzincan Binali Yildirim University, Erzincan, Turkey
17: Also at CERN, European Organization for Nuclear Research, Geneva,
Switzerland
18: Also at RWTH Aachen University, III. Physikalisches Institut A, Aachen,
Germany
19: Also at University of Hamburg, Hamburg, Germany
20: Also at Brandenburg University of Technology, Cottbus, Germany
21: Also at Institute of Physics, University of Debrecen, Debrecen, Hungary,
Debrecen, Hungary
22: Also at Institute of Nuclear Research ATOMKI, Debrecen, Hungary
23: Also at MTA-ELTE Lendület CMS Particle and Nuclear Physics Group, Eötvös
Loránd University, Budapest, Hungary, Budapest, Hungary
24: Also at IIT Bhubaneswar, Bhubaneswar, India, Bhubaneswar, India
25: Also at Institute of Physics, Bhubaneswar, India
26: Also at G.H.G. Khalsa College, Punjab, India
27: Also at Shoolini University, Solan, India
28: Also at University of Hyderabad, Hyderabad, India
29: Also at University of Visva-Bharati, Santiniketan, India
30: Now at INFN Sezione di Bari a, Università di Bari b, Politecnico di Bari
c, Bari, Italy
31: Also at Italian National Agency for New Technologies, Energy and
Sustainable Economic Development, Bologna, Italy
32: Also at Centro Siciliano di Fisica Nucleare e di Struttura Della Materia,
Catania, Italy
33: Also at Riga Technical University, Riga, Latvia, Riga, Latvia
34: Also at Malaysian Nuclear Agency, MOSTI, Kajang, Malaysia
35: Also at Consejo Nacional de Ciencia y Tecnología, Mexico City, Mexico
36: Also at Warsaw University of Technology, Institute of Electronic Systems,
Warsaw, Poland
37: Also at Institute for Nuclear Research, Moscow, Russia
38: Now at National Research Nuclear University ’Moscow Engineering Physics
Institute’ (MEPhI), Moscow, Russia
39: Also at St. Petersburg State Polytechnical University, St. Petersburg,
Russia
40: Also at University of Florida, Gainesville, USA
41: Also at Imperial College, London, United Kingdom
42: Also at P.N. Lebedev Physical Institute, Moscow, Russia
43: Also at California Institute of Technology, Pasadena, USA
44: Also at Budker Institute of Nuclear Physics, Novosibirsk, Russia
45: Also at Faculty of Physics, University of Belgrade, Belgrade, Serbia
46: Also at Università degli Studi di Siena, Siena, Italy
47: Also at INFN Sezione di Pavia a, Università di Pavia b, Pavia, Italy,
Pavia, Italy
48: Also at National and Kapodistrian University of Athens, Athens, Greece
49: Also at Universität Zürich, Zurich, Switzerland
50: Also at Stefan Meyer Institute for Subatomic Physics, Vienna, Austria,
Vienna, Austria
51: Also at Burdur Mehmet Akif Ersoy University, BURDUR, Turkey
52: Also at Şırnak University, Sirnak, Turkey
53: Also at Department of Physics, Tsinghua University, Beijing, China,
Beijing, China
54: Also at Near East University, Research Center of Experimental Health
Science, Nicosia, Turkey
55: Also at Beykent University, Istanbul, Turkey, Istanbul, Turkey
56: Also at Istanbul Aydin University, Application and Research Center for
Advanced Studies (App. & Res. Cent. for Advanced Studies), Istanbul, Turkey
57: Also at Mersin University, Mersin, Turkey
58: Also at Piri Reis University, Istanbul, Turkey
59: Also at Gaziosmanpasa University, Tokat, Turkey
60: Also at Ozyegin University, Istanbul, Turkey
61: Also at Izmir Institute of Technology, Izmir, Turkey
62: Also at Bozok Universitetesi Rektörlügü, Yozgat, Turkey
63: Also at Marmara University, Istanbul, Turkey
64: Also at Kafkas University, Kars, Turkey
65: Also at Istanbul Bilgi University, Istanbul, Turkey
66: Also at Hacettepe University, Ankara, Turkey
67: Also at Adiyaman University, Adiyaman, Turkey
68: Also at Vrije Universiteit Brussel, Brussel, Belgium
69: Also at School of Physics and Astronomy, University of Southampton,
Southampton, United Kingdom
70: Also at IPPP Durham University, Durham, United Kingdom
71: Also at Monash University, Faculty of Science, Clayton, Australia
72: Also at Bethel University, St. Paul, Minneapolis, USA, St. Paul, USA
73: Also at Karamanoğlu Mehmetbey University, Karaman, Turkey
74: Also at Bingol University, Bingol, Turkey
75: Also at Georgian Technical University, Tbilisi, Georgia
76: Also at Sinop University, Sinop, Turkey
77: Also at Mimar Sinan University, Istanbul, Istanbul, Turkey
78: Also at Texas A&M University at Qatar, Doha, Qatar
79: Also at Kyungpook National University, Daegu, Korea, Daegu, Korea