EXO-17-001

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$Id:EXO-17-001.tex4372872017-12-0218:19:41Zcmantill$

EXO-17-001

# Search for low mass vector resonances decaying into quark-antiquark pairs in
proton-proton collisions at $\sqrt{s}=13\TeV$

###### Abstract

A search for narrow vector resonances decaying into quark-antiquark pairs is
presented. The analysis is based on data collected in proton-proton collisions
at $\sqrt{s}=13\TeV$ with the CMS detector at the LHC, corresponding to an
integrated luminosity of 35.9. The hypothetical resonance is produced with
sufficiently high transverse momentum that its decay products are merged into
a single jet with two-prong substructure. A signal would be identified as a
peak over a smoothly falling background in the distribution of the invariant
mass of the jet, using novel jet substructure techniques. No evidence for such
a resonance is observed within the mass range of 50–300. Upper limits at 95%
confidence level are set on the production cross section, and presented in a
mass-coupling parameter space. The limits further constrain simplified models
of dark matter production involving a mediator interacting between quarks and
dark matter particles through a vector or axial-vector current. In the
framework of these models, the results are the most sensitive to date,
extending for the first time the search region to masses below 100.

##  0.1 Introduction

Many extensions of the standard model (SM) predict the existence of new
resonances that couple to quarks (q) [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]. The
first searches for such particles were reported by the UA1 [12] and UA2 [13,
14] experiments using $\sqrt{s}=630\GeV$ collisions at the CERN
$\mathrm{Sp\bar{p}S}$, and were extended to larger values of resonance masses
by the CDF [15, 16, 17, 18, 19] and D0 [20] experiments using $\sqrt{s}=1.8$
and $1.96\TeV$ collisions at the Fermilab Tevatron. At the CERN LHC, the
searches in proton-proton (pp) collisions at $\sqrt{s}=7$, 8 and $13\TeV$
performed by the ATLAS [21, 22, 23, 24, 25, 26, 27] and CMS [28, 29, 30, 31,
32, 33, 34, 35] Collaborations have mostly focused on the production of heavy
particles. For resonance masses below 1, the sensitivity is limited by high
trigger thresholds and by the large expected backgrounds, notably from SM
events consisting of jets produced through the strong interaction, referred to
here as QCD multijet events.

These difficulties can be avoided by an approach focused on the events where
at least one high transverse momentum () jet from initial-state radiation
(ISR) is produced in association with a light resonance decaying into a
$\PQq\PAQq$ pair. The ISR requirement provides enough energy in the event to
satisfy the trigger, either by the ISR jet or by the resonance itself. The
minimum of the resonance considered in this search is sufficiently high that
the hadronization products of the daughter quarks merge and are reconstructed
as a single, large-radius jet. The only previous search in this topology to
place constraints on resonance masses below 300was by the CMS Collaboration,
applying this technique to data collected at the LHC in 2015 [36].

In the current paper, the results of a search for leptophobic vector
resonances () decaying to quark-antiquark pairs in pp collisions at
$\sqrt{s}=13\TeV$ are reported, using data collected by the CMS detector in
2016, corresponding to an integrated luminosity of $35.9\fbinv$. The search is
performed by looking for a narrow resonance peak in the continuous jet mass
distribution. The analysis exploits a new substructure variable that is
decorrelated from the jet mass and and preserves the shape of the jet mass
distribution used in the search. The jet is required to have the two-prong
substructure expected from the signal. The dominant background from SM QCD
multijet production is estimated from a signal-depleted control region created
by inverting the substructure requirement. The signal yield is extracted by
simultaneously fitting the signal and control regions, while requiring that
the ratio of QCD components in each region is described by a smooth two-
dimensional function of jet mass and . The W+jets and Z+jets background
components are estimated from simulation and the top quark background
contribution is obtained from simulation corrected with scale factors derived
from a -enriched control sample.

Results are interpreted within the framework of a leptophobic vector resonance
model, and are also used to set limits on the existence of generic vector-like
resonances decaying into quarks [37]. Limits are also set in the context of a
simplified model of dark matter (DM) production at the LHC, in which the
mediators couple only to quarks and DM particles [38].

##  0.2 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 are a silicon pixel and strip tracker, a lead tungstate crystal
electromagnetic calorimeter (ECAL), and a brass and scintillator hadron
calorimeter (HCAL), each composed of a barrel and two endcap sections. Forward
calorimeters extend the pseudorapidity ($\eta$) 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 are selected using a two-tiered trigger system [39]. The first level,
composed of custom hardware processors, uses information from the calorimeters
and muon detectors to select events of interest in a time interval of less
than 4. The second level, known as the high-level trigger (HLT), consists of a
farm of processors running a version of the full event reconstruction software
optimized for fast processing, and further reduces the event rate from around
100 kHz to less than 1 kHz, before data storage.

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. [40].

##  0.3 Event simulation and selection

###  0.3.1 Simulated samples

Simulated samples of the resonance decaying into a quark-antiquark pair are
generated at leading order (LO) with the 2.2.3 generator [41] with up to 3
extra jets in matrix element calculations. The dominant SM backgrounds arise
from multijet and /+ jets processes. These backgrounds are simulated at LO
using the generator with the MLM matching [42] between jets from matrix
element calculations and from parton showers, while the 2.0 [43] generator at
next-to-leading order (NLO) precision is used to model the subdominant
contribution from pair and single top quark production. All signal and
background generators are interfaced with 8.212 [44], with the CUETP8M1
underlying event tune [45], to simulate parton showering and hadronization
effects. The generated events are further processed through a [46] simulation
of the CMS detector. The parton distribution function (PDF) set NNPDF3.0 [47]
is used to produce all simulated samples, with the accuracy (LO or NLO)
determined by the generator used. For events containing and bosons, we apply
higher-order QCD and electroweak (EW) dependent corrections to improve the
modeling of the distribution of and events, following Refs. [48, 49, 50, 51,
52]. The same NLO QCD corrections that are applied to the and simulation are
also applied to the signal simulation. However, since the coupling of the
mediator differs from that of the boson, the equivalent NLO EW corrections are
not applied to the signal model.

###  0.3.2 Event reconstruction and selection

The CMS particle-flow (PF) event algorithm [53] reconstructs and identifies
individual particles with an optimized combination of information from the
various elements of the CMS detector. Each particle candidate is classified as
either an electron, a muon, a photon, or a charged or neutral hadron. The
energy of photons is obtained directly from the ECAL measurement, corrected
for zero-suppression effects. The energy of electrons is determined from a
combination of the electron momentum at the primary interaction vertex as
determined by the tracker, the energy of the corresponding ECAL cluster, and
the energy sum of all bremsstrahlung photons spatially compatible with
originating from the electron track. The energy of muons is obtained from the
curvature of the corresponding track. The energy of charged hadrons is
determined from a combination of their momentum measured in the tracker and
the matching ECAL and HCAL energy deposits, corrected for zero-suppression
effects and for the response function of the calorimeters to hadronic showers.
Finally, the energy of neutral hadrons is obtained from the corresponding
corrected ECAL and HCAL energy. The missing transverse momentum vector is
defined as the negative vectorial sum of the transverse momenta of all the
particles identified in the event, and its magnitude is referred to as
$p_{\mathrm{T}}^{\mathrm{miss}}$.

The PF candidates are clustered into jets using the anti-algorithm [54, 55].
Jets are clustered with distance parameters of 0.4 and 0.8, and are referred
to as AK4 and AK8 jets, respectively. To mitigate the impact of particles
arising from additional proton-proton interactions within the same or adjacent
bunch crossings (pileup), weights calculated with the pileup-per-particle
identification algorithm [56] are applied to each PF candidate prior to jet
clustering, based on the likelihood of it coming from the hard-scattering
vertex. Further corrections are applied to simulated jet energies as a
function of jet $\eta$ and to match the observed detector response [57, 58].

This search focuses on events in which a high-jet from a merged
$\PZpr\to\PQq\PAQq$ recoils against another high-ISR jet. A combination of
several online signatures is required for the trigger selection, all requiring
the total hadronic transverse energy in the event () or the jet to exceed a
certain threshold. In addition, soft radiation remnants are removed with the
jet trimming technique [59] before the mass selection, allowing the and jet
trigger thresholds to be reduced, and improving the signal acceptance. To be
fully efficient with respect to the trigger requirement, we require at least
one AK8 jet with $\pt>500\GeV$ and $|\eta|<2.5$. Additional quality criteria
are applied to the jets in order to remove spurious jet-like features
originating from isolated noise patterns in the calorimeters or the tracker.
The efficiency of these jet quality requirements for signal events is above
$99\%$. In order to reduce backgrounds from SM EW processes, events are
removed if they contain identified and isolated electrons, muons, or taus with
$\pt>10\GeV$ and $|\eta|<2.5$, $2.4$, or $2.3$, respectively, according to the
isolation criteria in [48].

In the subsequent offline analysis, the most energetic jet in the event is
assumed to correspond to the $\PZpr\to\PQq\PAQq$ system, and is reconstructed
as a single AK8 jet. The search is performed using the distribution of the jet
mass groomed with the soft-drop algorithm ($m_{\text{SD}}$), which is an
extension of the modified mass drop tagger [60, 61] that removes soft and
wide-angle radiation produced by parton shower activity, pileup interactions,
and the underlying event from the jet. Jets are groomed using the parameters
$z_{\text{cut}}=0.1$ and $\beta=0$. Here, $z_{\text{cut}}$ specifies
subleading the energy fraction relative to the whole jet at which jet
declustering into subjet pairs is stopped. The parameter $\beta$ adds
additional angular requirements on the jet declustering. For $\beta=0$, these
requirements are neglected, and approximately the same fraction of energy is
groomed away regardless of the initial jet energy [61]. The soft-drop grooming
reduces the jet mass for QCD background jets when large masses arise from soft
gluon radiation. In contrast, the jet mass for merged $\PZpr\to\PQq\PAQq$ and
$\PW/\PZ\to\PQq\PAQq$ jets comes from the kinematic distributions of the
decay, and is largely unchanged by grooming. Figure 1 shows the distributions
of $m_{\text{SD}}$ for data and simulation, after the jet kinematic selection.

Figure 1: Distributions of data (points) and simulated backgrounds
(histograms), of the leading $\pt$ jet soft-drop mass after the jet kinematic
selection. Dashed lines illustrate the signal contribution for different
$\PZpr$ boson masses. The multijet processes (QCD) dominate the background
component, with subdominant contributions from inclusive SM $\PW$, $\PZ$, and
$\ttbar$ and single top quark processes. The QCD simulation is corrected by an
overall factor of 0.74 to match the data yield.

In this paper, the dimensionless scaling variable $\rho$ [60, 62], defined as
$\rho=\ln(m_{\text{SD}}^{2}/\pt^{2})$, is used in the characterization of the
correlation of jet substructure variables with the jet mass and . For QCD
jets, the distribution of $\rho$ is approximately invariant under a change of
jet , in the region where perturbative contributions dominate and scale as
($m_{\text{SD}}/\pt$). This property does not hold in two regimes: in the low
mass region below $\rho\approx-6$, where non-perturbative effects are large
and scale as ($1/m_{\text{SD}}$) instead, and in the high mass region above
$\rho\approx-2$. The departure from $\rho$ invariance in the latter case
arises because the cone size of the AK8 jets is insufficient to provide
complete containment at high masses. Consequently, only events in the range
$-5.5<\rho<-2.0$ are considered. This requirement is fully efficient for the
boson signal and roughly translates to a $m_{\text{SD}}$ range from 25to 185at
$\pt=500\GeV$.

In addition to the jet mass, the observable $N_{2}^{1}$ [63] is used to
discriminate the two-prong structure of the jets from the $\PZpr\to\PQq\PAQq$
decay from the hadronization products of single light quarks or gluons, which
are overwhelmingly one-prong. This jet substructure variable is defined from a
combination of generalized energy correlation functions ${{}_{v}e_{n}}$,
sensitive to correlations of $v$ pairwise angles among $n$-jet constituents
[63]. In particular, the 2-point (${}_{1}e_{2}$) and 3-point (${}_{2}e_{3}$)
correlation functions are defined as:

${}_{1}e_{2}$ $\displaystyle=\sum_{1\leq i<j\leq n}{z_{i}z_{j}\Delta
R_{ij}}~{},$ (1) ${}_{2}e_{3}$ $\displaystyle=\sum_{1\leq i<j<k\leq
n}{z_{i}z_{j}z_{k}\min\\{\Delta R_{ij}\Delta R_{ik},\Delta R_{ij}\Delta
R_{jk},\Delta R_{ik}\Delta R_{jk}\\}}~{},$ (2)

where $z_{i}$ represents the energy fraction of the constituent $i$ in the jet
and $\Delta R_{ij}$ is the angular separation between constituents $i$ and
$j$. For a two-prong structure, signal jets have a stronger 2-point
correlation than a 3-point correlation. The discriminant variable $N_{2}^{1}$
is then constructed via the ratio:

$\quad N_{2}^{1}=\frac{{}_{2}e_{3}}{(_{1}e_{2})^{2}}~{}.$ (3)

The energy correlation functions are computed from the jet constituents after
the soft-drop grooming has been applied, thereby reducing their dependence on
the jet mass and $\pt$ [63].

The $N_{2}^{1}$ observable has excellent performance in discriminating two-
prong signal jets from multijet QCD background jets [63]. However, $N_{2}^{1}$
and similar variables are correlated with the jet mass and . A selection based
on $N_{2}^{1}$ would distort the jet mass distribution, with the amount of
distortion depending on the of the jet. This would make the search for a
resonant peak in the jet mass distribution, over a large range of ,
particularly challenging.

The key feature of our approach is that the application of the substructure
requirement preserves the shape of the soft-drop jet mass distribution.
Improving on the decorrelation procedure proposed in Ref. [62], we apply a DDT
(designed decorrelated tagger) transformation of $N_{2}^{1}$ to
$N_{2}^{1,\text{DDT}}$. It is defined as $N_{2}^{1,\text{DDT}}(\rho,\pt)$
$\equiv$ $N_{2}^{1}(\rho,\pt)-X_{(5\%)}(\rho,\pt)$, where $X_{(5\%)}$ is
derived from the simulated $N_{2}^{1}$ distribution and illustrated in Fig. 2.
We require events to pass the $N_{2}^{1,\text{DDT}}(\rho,\pt)<0$ selection,
such that we select a fixed 5% of QCD multijet events independent of $\rho$
and . The distribution of $X_{(5\%)}$ is smoothed using a distance weighted
k-nearest neighbor (kNN) approach [64]. The chosen percentile maximizes the
sensitivity to the boson signal.

Figure 2: The distribution of $X_{(5\%)}$ used to define the
$N_{2}^{1,\text{DDT}}$ variable, corresponding to the 5% quantile of the
$N_{2}^{1}$ distribution in simulated multijet events. The distribution is
shown as a function of the jet $\rho$ and $\pt$ and smoothed using a kNN
approach [64]. The $N_{2}^{1}$ distribution is mostly insensitive to the jet
$\rho$ and $\pt$ in the kinematic phase space considered for this analysis
($-5.5<\rho<-2.0$). Residual correlations in simulation are corrected by
applying a decorrelation procedure that yields the $N_{2}^{1,\text{DDT}}$
variable.

The distributions of $N_{2}^{1,\text{DDT}}$ for data and simulation are shown
in Fig. 3 after the jet $\pt>500\GeV$ requirement. Since there is a visible
disagreement between simulation and data, the multijet background is estimated
from data, as described in the next section. Additional distributions of
kinematic observables for data and simulation are available in Appendix .8.

Figure 3:  Distributions of data (points) and simulated backgrounds
(histograms), of the $N_{2}^{1,\text{DDT}}$ variable for the leading $\pt$ jet
after the kinematic selection. Dashed lines illustrate the signal contribution
for different $\PZpr$ boson masses. The multijet processes (QCD) dominate the
background component, with subdominant contributions from inclusive SM $\PW$,
$\PZ$, and $\ttbar$ and single top quark processes. The QCD simulation is
corrected by an overall factor of 0.74 to match the data yield.

##  0.4 Background estimate

The search is performed by looking for a resonance in the soft-drop mass
distribution over background contributions dominated by QCD multijet events
and smaller contributions from $\PW(\PQq^{\prime}\PAQq)$+jets,
$\PZ(\PQq\PAQq)$+jets, and top quark background processes.

To model the background contribution from pair and single top quark production
we utilize simulation with data-driven corrections based on a dedicated
control region. This region has the same kinematic requirements as the signal
region but with the muon veto inverted. The muon is selected using dedicated
muon triggers and is required to have $\pt>100\GeV$ and $|\eta|<2.1$ and to be
in the opposite hemisphere to the selected AK8 jet. To enrich the contribution
and reduce the multijet contamination, at least one AK4 jet with $\pt>50\GeV$
is required to pass the b-tagging medium selection based on the combined
secondary vertices version-2 algorithm [65], which identifies AK4 jets that
originate from the hadronization of b quarks. Separate scale factors correct
the overall top quark background normalization and the $N_{2}^{\text{1,DDT}}$
efficiency for mistagging jets from top quark decays. These scale factors are
$\mathrm{SF}^{\text{\ttbar}}_{\mathrm{norm}}=0.75\pm 0.10$ and
$\mathrm{{SF}^{t}_{\mathrm{mistag}}}=0.83\pm 0.03$, respectively.

Subdominant backgrounds arising from resonant SM processes ($\PW$/$\PZ$\+
jets) are estimated from simulations that include corrections to the shape and
normalization from higher order NLO QCD and EW calculations. Additional data-
to-simulation corrections for the jet mass shapes and $N_{2}^{\text{1,DDT}}$
tagging efficiencies are applied to the simulation. These corrections are
evaluated from a control region rich in merged hadronic $\PW$ bosons, as
further explained below.

We estimate the main QCD multijet event background by taking advantage of the
decorrelation of $N_{2}^{\text{1,DDT}}$ from $\rho$ and . The fraction of
events passing the $N_{2}^{\text{1,DDT}}$ selection is, by construction, a
constant 5% in simulated multijet events. The decorrelation ensures that the
events passing and failing the selection have the same shape of the QCD jet
mass distribution, and their ratio, the “pass-to-fail ratio” $R_{\rm p/f}$, is
constant for simulated multijet events. The prediction of events passing the
selection can then be expressed as:

$n^{\mathrm{QCD}}_{\mathrm{pass}}(m_{\text{SD}},\pt)=R_{\rm
p/f}(\rho(m_{\text{SD}},\pt),\pt)\,n^{\mathrm{QCD}}_{\mathrm{fail}}(m_{\text{SD}},\pt)~{},$
(4)

where $n^{\mathrm{QCD}}_{\mathrm{pass}}$ and
$n^{\mathrm{QCD}}_{\mathrm{fail}}$ are the number of passing and failing
events in a given $m_{\text{SD}}$, bin. This procedure is illustrated
schematically in Fig. 4. Since the distribution of $\rho$ is expected to be
invariant under a change of , $R_{\rm p/f}$ is parametrized as a function of
$\rho$, which is in turn expressed as a function of $m_{\text{SD}}$ and .

Figure 4:  A schematic of the background estimation method. The pass-to-fail
ratio, $R_{\rm p/f}(\rho(m_{\text{SD}},\pt))$, is defined from the events
passing and failing the $N_{2}^{\text{1,DDT}}$ selection. The variable
$N_{2}^{\text{1,DDT}}$ is constructed so that, for simulated multijet events,
$R_{\rm p/f}$ is constant (left). To account for residual differences between
data and simulation, $R_{\rm p/f}$ is extracted by performing a two-
dimensional fit to data in ($\rho,\pt$) space (right).

Owing to residual differences between data and simulation, the correction
$R_{\rm p/f}(\rho,\pt)$ is allowed to deviate from a constant. The deviation
is modeled by expanding $R_{\rm p/f}(\rho,\pt)$ into a polynomial series in
orders of $\rho$ and $\pt$:

$\displaystyle R_{\rm p/f}(\rho,\pt)$
$\displaystyle=\epsilon_{\mathrm{QCD}}(1+a_{01}\pt+a_{02}\pt^{2}+\cdots$ (5)
$\displaystyle+(a_{10}+a_{11}\pt+a_{12}\pt^{2}+\cdots)\rho$
$\displaystyle+(a_{20}+a_{21}\pt+a_{22}\pt^{2}+\cdots)\rho^{2}+\cdots).$

The coefficients $\epsilon_{\mathrm{QCD}}$ and $a_{k\ell}$ have no external
constraints but are determined from a simultaneous fit to the data events
passing and failing the substructure requirement, together with the signal
yield. The number of required coefficients in the fit is determined with a
Fisher $F$-test on data [66] by iteratively adding polynomial orders. The
optimum choice is found to be of fourth order in $\rho$ and third order in .
The fact that $R_{\rm p/f}$ varies slowly across the $m_{\text{SD}}$–domain is
essential, since it allows one to estimate the background under a narrow
signal resonance based on the events across the whole jet mass range.

##  0.5 Systematic uncertainties

Uncertainties in the multijet background arise from the fit parameter
uncertainties in the pass-to-fail ratio fit described in Eq. (5). The
uncertainties in the top quark background normalization (10%) and
$N_{2}^{\text{1,DDT}}$ mistag (2%) scale factors are propagated to the signal
extraction through the fit.

The systematic effects for the shapes and normalization of the , backgrounds,
and signal components are strongly correlated since they are affected by
similar systematic mismeasurements. We constrain the jet mass scale, the jet
mass resolution, and the $N_{2}^{\text{1,DDT}}$ selection efficiency using a
sample of merged boson jets in semileptonic events in data. In this region,
events are required to have an energetic muon with $\pt>100\GeV$,
$p_{\mathrm{T}}^{\mathrm{miss}}>80\GeV$, a high-AK8 jet with $\pt>200\GeV$,
and a b-tagged AK4 jet separated from the AK8 jet by $\Delta R>0.8$. Using the
same $N_{2}^{\text{1,DDT}}$ requirement described above, we define samples
with events that pass and fail the selection for merged boson jets in data and
simulation, shown in Fig. 5. A simultaneous fit to the two samples is
performed in order to extract the selection efficiency of a merged jet in
simulation and in data. We measure the data-to-simulation scale factor for the
$N_{2}^{\text{1,DDT}}$ selection to be $0.88\pm 0.10$. The mass scale between
data and simulation is found to be $1.10\pm 0.05$. The jet mass resolution
data-to-simulation scale factor is measured to be $1.14\pm 0.06$. These scale
factors determine the initial distributions of the jet mass for the , boson,
and signal and they are further constrained in the fit to data because of the
presence of the and resonances in the jet mass distribution. To account for
potential deviations due to missing higher-order corrections to the simulated
boson distributions, uncertainties are assumed in the and boson yields that
are -dependent. An additional systematic uncertainty is included to account
for potential differences between the and boson higher-order corrections.
Finally, uncertainties associated to the jet energy resolution [57], trigger
efficiency, lepton veto efficiency, and the integrated luminosity
determination [67] are also applied to the , boson, and boson signal yields. A
quantitative summary of the systematic effects considered is listed in Table
0.5.

Figure 5:  Soft-drop jet mass distributions that pass (left) and fail (right)
the $N_{2}^{\text{1,DDT}}$ selection in the semileptonic $\ttbar$ sample.
Results of fits to data and simulation are shown.

Summary of the systematic uncertainties for signal and background processes
and their relative size. The symbol △ denotes uncertainties decorrelated per
$\pt$ bin in the 500–1000range. The symbol † denotes a shape uncertainty in
the peaking SM $\PW$ and $\PZ$ boson backgrounds and $\PZpr$ boson signal
shape. A long dash (—) indicates that the uncertainty does not apply.
Systematic source Multijet / Lepton veto efficiency — 0.5% 0.5% — Jet mass
scale† — 0.5% 0.5% — Jet mass scale (dependence) †△ — 0.5–2% 0.5–2% — Trigger
efficiency — 2% 2% — Top quark mistag rate — — — 2% Integrated luminosity —
2.5% 2.5% — Multijet fit parameters 1–3% — — — $N_{2}^{\text{1,DDT}}$
selection efficiency — 9% 9% — Top quark background normalization — — — 10%
Jet energy resolution† — 10% 10% — NLO QCD corrections — 10% 10% — NLO EW
corrections△ — — 15–35% — NLO EW /decorrelation — — 5–15% —

To validate the robustness of the fit, we perform a goodness-of-fit test and
bias tests using pseudo-experiments and injecting a simulated signal, for
different values of boson mass. No significant bias is observed. As a further
test of fit robustness, we split the region failing the $N_{2}^{1,DDT}$
selection into two smaller regions mimicking the passing and failing regions
in the signal extraction fit. The mimicked passing-like region corresponds to
a background efficiency of 60–65% and the mimicked failing-like region
corresponds to an efficiency of 65–100%. We repeat our background estimation
procedure on this selection as if the 60–65% efficiency region were the
passing region. We find negligible biases in the fitted signal strength.

##  0.6 Results

We combine the estimates of the various SM background processes and search for
a potential signal from a resonance in the mass range from 50 to 300. A binned
maximum likelihood fit to the observed shape of the soft-drop jet mass
distribution is performed simultaneously in the passing and failing regions of
five ranges whose boundaries are: 500, 600, 700, 800, 900 and 1000. The number
of observed events is consistent with the predicted background from SM
processes. Figure 6 shows the soft-drop jet mass distribution for data and
measured background contributions in the different ranges for a mass of 135;
the and boson contributions are clearly visible in the data. The
$m_{\text{SD}}$ distribution for data in the combined ranges is available in
Appendix .8.

Figure 6: Soft-drop jet mass distribution for the different ranges of the fit
from 500 to 1000. Data are shown as black points. The multijet background
prediction, including uncertainties, is shown by the shaded bands.
Contributions from the and boson, and top quark background processes are
shown, scaled up by a factor of 3 for clarity. A hypothetical boson signal at
a mass of 135is also indicated. In the bottom panel, the ratio of the data to
the background prediction, including uncertainties, is shown. The scale on the
x-axis differs for each range due to the kinematic selection on $\rho$.

The results are interpreted in terms of 95% confidence level (CL) upper limits
on the production cross section. Upper limits are computed using the modified
frequentist approach for confidence levels (CLs); taking the profile
likelihood as the test statistic [68, 69] in the asymptotic approximation
[70]. They are shown as a function of the resonance mass in Fig. 7 (left),
where they are compared to cross sections for a model of a leptophobic
resonance with quark coupling $g_{\rm q^{\prime}}$ value of either $0.17$ or
$0.08$ that are close to our current sensitivity. Systematic uncertainties are
treated as nuisance parameters, which are modeled with log-normal priors and
profiled over in the limit calculations. The maximum local observed p-value
corresponds to $2.9$ standard deviations from the background-only expectation
at a boson mass of 115, and the global significance, calculated over the
probed mass range [71], corresponds to approximately $2.2$ standard
deviations.

Upper limits on the signal cross section are translated into the coupling
$g_{\rm q^{\prime}}$ as a function of boson mass, related to the coupling
convention of Ref. [37] by $g_{\rm q^{\prime}}=g_{\rm B}/6$. Coupling values
above the solid curves are excluded. In Fig. 7 (right), we show previous
results from UA2, CDF, ATLAS and CMS experiments. Indirect constraints from
the hadronic boson partial width measurement and limits from the UA2 and CDF
experiments are interpreted from [37].

Figure 7:  The 95% CL upper limits on the $\PZpr$ boson production cross
section compared to theoretical cross sections (left) and on the quark
coupling $g_{\rm q^{\prime}}$ as a function of resonance mass for a
leptophobic $\PZpr$ resonance that only couples to quarks (right). The
observed limits (solid), expected limits (dashed) and their variation at the 1
and 2 standard deviation levels (shaded bands) are shown. Limits from other
relevant searches and an indirect constraint on a potential $\PZpr$ signal
from the SM $\PZ$ boson width [72] are also shown.

The results of this analysis can be used to constrain simplified models of DM.
Figure 8 shows the excluded values at 95% CL of mediator mass ($m_{\rm Med}$)
as a function of the dark matter particle mass ($m_{\rm DM}$) for vector
mediators, in simplified models that assume a leptophobic mediator that
couples only to quarks and DM particles [73, 38]. Limits are shown for a
choice of universal quark coupling $g_{\rm q}=0.25$ and a DM coupling $g_{\rm
DM}=1.0$. The difference in limits between axial-vector and vector mediator
couplings is small and thus only constraints for the latter coupling scenario
are shown. The excluded range of mediator mass (red) is between 50 and 300.
The upper bound decreases to 240when $m_{\rm Med}>2m_{\rm DM}$, because the
branching fraction (BR) to $\PQq\PAQq$ decreases as the BR to DM becomes
kinematically favorable. If $m_{\rm Med}<2m_{\rm DM}$, the mediator cannot
decay to DM particles and the dijet cross section from the mediator model
becomes identical to that in the leptophobic model, meaning that the limits on
the mediator mass in Fig. 8 are identical to the limits on the mass with a
coupling $g_{\rm q^{\prime}}=g_{\rm q}=0.25$. For axial-vector mediators, the
excluded values of mediator mass are expected to be identical to the excluded
values in Fig. 8 when $m_{\rm DM}>m_{\rm Med}/2$ or $m_{DM}=0$, with
differences only expected in the transition region $m_{\rm Med}\simeq 2m_{\rm
DM}$. Additional limits (blue) in Fig. 8 come from traditional dijet searches
[35].

Figure 8:  The 95% CL observed (solid red) and expected (dashed red) excluded
regions in the plane of dark matter particle mass ($m_{\rm DM}$) vs. mediator
mass ($m_{\rm Med}$), for vector mediators. A branching fraction of $100\%$ is
assumed for a leptophobic vector mediator decaying to dijets. The exclusion is
computed for a quark coupling choice $g_{q}=0.25$ and for a dark matter
coupling $g_{\rm DM}=1$. The excluded regions from the dijet resolved analysis
(blue dot dashed lines) using early 2016 data [35] are also shown. Results are
compared to constraints from the cosmological relic density of DM (light gray)
determined from astrophysical measurements [74, 75] and MadDM version 2.0.6
[76, 77] as described in Ref. [78].

##  0.7 Summary

A search for a vector resonance ($\PZpr$) decaying into a quark-antiquark pair
and reconstructed as a single jet has been presented, using a data set
comprising proton-proton collisions at $\sqrt{s}=13\TeV$, corresponding to an
integrated luminosity of 35.9. Novel substructure techniques are employed to
identify a jet containing a $\PZpr$ boson candidate over a smoothly falling
soft-drop jet mass distribution in data. No significant excess above the SM
prediction is observed, and 95% confidence level upper limits are set on the
$\PZpr$ boson coupling to quarks, $g_{\rm q^{\prime}}$, as a function of the
$\PZpr$ boson mass. Coupling values of $g_{\rm q^{\prime}}>0.25$ are excluded
over the $\PZpr$ mass range from 50 to 300, with strong constraints for masses
less than 200. The results obtained for masses from 50 to 100represent the
first direct limits to be published in this range. Limits are set on a
simplified model of dark matter mediators that only couple to quarks and dark
matter particles, excluding vector mediators with masses between 50 and 300,
and using a universal quark coupling $g_{\rm q}=0.25$ and a dark matter
coupling $g_{\rm DM}=1.0$.

###### 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 centres 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: BMWFW and FWF (Austria); FNRS and FWO (Belgium); CNPq,
CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC
(China); COLCIENCIAS (Colombia); MSES and CSF (Croatia); RPF (Cyprus);
SENESCYT (Ecuador); MoER, ERC IUT, and ERDF (Estonia); Academy of Finland,
MEC, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF
(Germany); GSRT (Greece); OTKA and NIH (Hungary); DAE and DST (India); IPM
(Iran); SFI (Ireland); INFN (Italy); MSIP and NRF (Republic of Korea); LAS
(Lithuania); MOE and UM (Malaysia); BUAP, CINVESTAV, CONACYT, LNS, SEP, and
UASLP-FAI (Mexico); MBIE (New Zealand); PAEC (Pakistan); MSHE and NSC
(Poland); FCT (Portugal); JINR (Dubna); MON, RosAtom, RAS, RFBR and RAEP
(Russia); MESTD (Serbia); SEIDI, CPAN, PCTI and FEDER (Spain); Swiss Funding
Agencies (Switzerland); MST (Taipei); ThEPCenter, IPST, STAR, and NSTDA
(Thailand); TUBITAK and TAEK (Turkey); NASU and SFFR (Ukraine); STFC (United
Kingdom); DOE and NSF (USA). Individuals have received support from the Marie-
Curie programme and the European Research Council and Horizon 2020 Grant,
contract No. 675440 (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 Ministry of Education, Youth and
Sports (MEYS) of the Czech Republic; the Council of Science and Industrial
Research, India; the HOMING PLUS programme of the Foundation for Polish
Science, cofinanced from European Union, Regional Development Fund, the
Mobility Plus programme 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 Programa Severo Ochoa del Principado de Asturias;
the Thalis and Aristeia programmes 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 Welch Foundation, contract C-1845; and the
Weston Havens Foundation (USA).

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##  .8 Supplementary materials

Figure 9:  Distributions of data (points) and simulated backgrounds
(histograms) of the leading jet $N_{2}^{1}$ (top left) and $\rho$ (top right)
observables, after the kinematic selection. The soft-drop jet mass
distributions for the passing (bottom left) and failing (bottom right) region,
defined by the $N_{2}^{1,\text{DDT}}$ selection, are also shown. The
decorrelation ensures that the shape of the multijet mass distribution in both
regions is unaffected by the $N_{2}^{1,\text{DDT}}$ selection for different
ranges. Dashed lines illustrate the signal contribution for different boson
masses. The multijet processes (QCD) dominate the background component, with
subdominant contributions from inclusive SM , , and and single top quark
processes. The QCD simulation is scaled by an overall factor of 0.74 to match
the data yield. Residual differences between data and simulation demonstrate
the need for a background estimation method based on control samples in data.
Figure 10:  Soft-drop jet mass distribution for the passing region and
combined categories. The multijet background prediction in the passing region
is obtained using the failing region and the pass–fail ratio $R_{\rm
p/f}(m_{\text{SD}},\pt)$. Data are shown as black points. The multijet
background prediction, including uncertainties, is shown by the shaded bands.
Contributions from the and boson, and top quark background processes are
shown, scaled up by a factor of 3 for clarity. A hypothetical boson signal at
a mass of 135is also indicated. The features at 45, 185, 220 and 255in the
$m_{\rm SD}$ distribution are due to the kinematic selection on $\rho$, which
affects each category differently. In the bottom panel, the ratio of the data
to the background prediction, including uncertainties, is shown.  Figure 11:
The observed p-value, obtained from the fit to data, as a function of the
boson mass. The maximum local observed p-value, at 115, is $1.72\times
10^{-3}$ and corresponds to $2.9$ standard deviations from the background-only
expectation, and the global p-value, calculated over the probed mass range,
corresponds to $0.0138$ and $2.2$ standard deviations.

##  .9 The CMS Collaboration

Yerevan Physics Institute, Yerevan, Armenia
A.M. Sirunyan, A. Tumasyan Institut für Hochenergiephysik, Wien, Austria
W. Adam, F. Ambrogi, E. Asilar, T. Bergauer, J. Brandstetter, E. Brondolin, M.
Dragicevic, J. Erö, M. Flechl, M. Friedl, R. Frühwirth1, V.M. Ghete, J.
Grossmann, J. Hrubec, M. Jeitler1, A. König, N. Krammer, I. Krätschmer, D.
Liko, T. Madlener, I. Mikulec, E. Pree, N. Rad, H. Rohringer, J. Schieck1, R.
Schöfbeck, M. Spanring, D. Spitzbart, W. Waltenberger, J. Wittmann, C.-E.
Wulz1, M. Zarucki Institute for Nuclear Problems, Minsk, Belarus
V. Chekhovsky, V. Mossolov, J. Suarez Gonzalez Universiteit Antwerpen,
Antwerpen, Belgium
E.A. De Wolf, D. Di Croce, X. Janssen, J. Lauwers, M. Van De Klundert, H. Van
Haevermaet, P. Van Mechelen, N. Van Remortel Vrije Universiteit Brussel,
Brussel, Belgium
S. Abu Zeid, F. Blekman, J. D’Hondt, I. De Bruyn, J. De Clercq, K. Deroover,
G. Flouris, D. Lontkovskyi, S. Lowette, I. Marchesini, S. Moortgat, L.
Moreels, Q. Python, K. Skovpen, S. Tavernier, W. Van Doninck, P. Van Mulders,
I. Van Parijs Université Libre de Bruxelles, Bruxelles, Belgium
D. Beghin, H. Brun, B. Clerbaux, G. De Lentdecker, H. Delannoy, B. Dorney, G.
Fasanella, L. Favart, R. Goldouzian, A. Grebenyuk, T. Lenzi, J. Luetic, T.
Maerschalk, A. Marinov, T. Seva, E. Starling, C. Vander Velde, P. Vanlaer, D.
Vannerom, R. Yonamine, F. Zenoni, F. Zhang2 Ghent University, Ghent, Belgium
A. Cimmino, T. Cornelis, D. Dobur, A. Fagot, M. Gul, I. Khvastunov3, D.
Poyraz, C. Roskas, S. Salva, M. Tytgat, W. Verbeke, N. Zaganidis Université
Catholique de Louvain, Louvain-la-Neuve, Belgium
H. Bakhshiansohi, O. Bondu, S. Brochet, G. Bruno, C. Caputo, A. Caudron, P.
David, S. De Visscher, C. Delaere, M. Delcourt, B. Francois, A. Giammanco, M.
Komm, G. Krintiras, V. Lemaitre, A. Magitteri, A. Mertens, M. Musich, K.
Piotrzkowski, L. Quertenmont, A. Saggio, M. Vidal Marono, S. Wertz, J. Zobec
Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, Brazil
W.L. Aldá Júnior, F.L. Alves, G.A. Alves, L. Brito, M. Correa Martins Junior,
C. Hensel, A. Moraes, M.E. Pol, P. Rebello Teles Universidade do Estado do Rio
de Janeiro, Rio de Janeiro, Brazil
E. Belchior Batista Das Chagas, W. Carvalho, J. Chinellato4, E. Coelho, E.M.
Da Costa, G.G. Da Silveira5, D. De Jesus Damiao, S. Fonseca De Souza, L.M.
Huertas Guativa, H. Malbouisson, M. Melo De Almeida, C. Mora Herrera, L.
Mundim, H. Nogima, L.J. Sanchez Rosas, A. Santoro, A. Sznajder, M. Thiel, E.J.
Tonelli Manganote4, F. Torres Da Silva De Araujo, A. Vilela Pereira
Universidade Estadual Paulista a, Universidade Federal do ABC b, São Paulo,
Brazil
S. Ahujaa, C.A. Bernardesa, T.R. Fernandez Perez Tomeia, E.M. Gregoresb, P.G.
Mercadanteb, S.F. Novaesa, Sandra S. Padulaa, D. Romero Abadb, J.C. Ruiz
Vargasa Institute for Nuclear Research and Nuclear Energy of Bulgaria Academy
of Sciences
A. Aleksandrov, R. Hadjiiska, P. Iaydjiev, M. Misheva, M. Rodozov, M. Shopova,
G. Sultanov University of Sofia, Sofia, Bulgaria
A. Dimitrov, L. Litov, B. Pavlov, P. Petkov Beihang University, Beijing, China
W. Fang6, X. Gao6, L. Yuan Institute of High Energy Physics, Beijing, China
M. Ahmad, J.G. Bian, G.M. Chen, H.S. Chen, M. Chen, Y. Chen, C.H. Jiang, D.
Leggat, H. Liao, Z. Liu, F. Romeo, S.M. Shaheen, A. Spiezia, J. Tao, C. Wang,
Z. Wang, E. Yazgan, H. Zhang, S. Zhang, J. Zhao State Key Laboratory of
Nuclear Physics and Technology, Peking University, Beijing, China
Y. Ban, G. Chen, J. Li, Q. Li, S. Liu, Y. Mao, S.J. Qian, D. Wang, Z. Xu
Universidad de Los Andes, Bogota, Colombia
C. Avila, A. Cabrera, L.F. Chaparro Sierra, C. Florez, C.F. González
Hernández, J.D. Ruiz Alvarez, M.A. Segura Delgado University of Split, Faculty
of Electrical Engineering, Mechanical Engineering and Naval Architecture,
Split, Croatia
B. Courbon, N. Godinovic, D. Lelas, I. Puljak, P.M. Ribeiro Cipriano, 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, A. Starodumov7, T. Susa
University of Cyprus, Nicosia, Cyprus
M.W. Ather, A. Attikis, G. Mavromanolakis, J. Mousa, C. Nicolaou, F. Ptochos,
P.A. Razis, H. Rykaczewski Charles University, Prague, Czech Republic
M. Finger8, M. Finger Jr.8 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
E. El-khateeb9, S. Elgammal10, A. Ellithi Kamel11 National Institute of
Chemical Physics and Biophysics, Tallinn, Estonia
R.K. Dewanjee, M. Kadastik, L. Perrini, M. Raidal, A. Tiko, C. Veelken
Department of Physics, University of Helsinki, Helsinki, Finland
P. Eerola, H. Kirschenmann, J. Pekkanen, M. Voutilainen Helsinki Institute of
Physics, Helsinki, Finland
J. Havukainen, J.K. Heikkilä, T. Järvinen, V. Karimäki, R. Kinnunen, T.
Lampén, K. Lassila-Perini, S. Laurila, S. Lehti, T. Lindén, P. Luukka, H.
Siikonen, E. Tuominen, J. Tuominiemi Lappeenranta University of Technology,
Lappeenranta, Finland
T. Tuuva IRFU, CEA, Université Paris-Saclay, Gif-sur-Yvette, France
M. Besancon, F. Couderc, M. Dejardin, D. Denegri, J.L. Faure, F. Ferri, S.
Ganjour, S. Ghosh, P. Gras, G. Hamel de Monchenault, P. Jarry, I. Kucher, C.
Leloup, E. Locci, M. Machet, J. Malcles, G. Negro, J. Rander, A. Rosowsky,
M.Ö. Sahin, M. Titov Laboratoire Leprince-Ringuet, Ecole polytechnique,
CNRS/IN2P3, Université Paris-Saclay, Palaiseau, France
A. Abdulsalam, C. Amendola, I. Antropov, S. Baffioni, F. Beaudette, P. Busson,
L. Cadamuro, C. Charlot, R. Granier de Cassagnac, M. Jo, S. Lisniak, A.
Lobanov, J. Martin Blanco, M. Nguyen, C. Ochando, G. Ortona, P. Paganini, P.
Pigard, R. Salerno, J.B. Sauvan, Y. Sirois, A.G. Stahl Leiton, T. Strebler, Y.
Yilmaz, A. Zabi, A. Zghiche Université de Strasbourg, CNRS, IPHC UMR 7178,
F-67000 Strasbourg, France
J.-L. Agram12, J. Andrea, D. Bloch, J.-M. Brom, M. Buttignol, E.C. Chabert, N.
Chanon, C. Collard, E. Conte12, X. Coubez, J.-C. Fontaine12, D. Gelé, U.
Goerlach, 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, R. Chierici, D. Contardo, P. Depasse, H.
El Mamouni, J. Fay, L. Finco, S. Gascon, M. Gouzevitch, G. Grenier, B. Ille,
F. Lagarde, I.B. Laktineh, M. Lethuillier, L. Mirabito, A.L. Pequegnot, S.
Perries, A. Popov13, V. Sordini, M. Vander Donckt, S. Viret Georgian Technical
University, Tbilisi, Georgia
T. Toriashvili14 Tbilisi State University, Tbilisi, Georgia
Z. Tsamalaidze8 RWTH Aachen University, I. Physikalisches Institut, Aachen,
Germany
C. Autermann, L. Feld, M.K. Kiesel, K. Klein, M. Lipinski, M. Preuten, C.
Schomakers, J. Schulz, V. Zhukov13 RWTH Aachen University, III. Physikalisches
Institut A, Aachen, Germany
A. Albert, E. Dietz-Laursonn, D. Duchardt, M. Endres, M. Erdmann, S. Erdweg,
T. Esch, R. Fischer, A. Güth, M. Hamer, T. Hebbeker, C. Heidemann, K.
Hoepfner, S. Knutzen, M. Merschmeyer, A. Meyer, P. Millet, S. Mukherjee, T.
Pook, M. Radziej, H. Reithler, M. Rieger, F. Scheuch, D. Teyssier, S. Thüer
RWTH Aachen University, III. Physikalisches Institut B, Aachen, Germany
G. Flügge, B. Kargoll, T. Kress, A. Künsken, T. Müller, A. Nehrkorn, A.
Nowack, C. Pistone, O. Pooth, A. Stahl15 Deutsches Elektronen-Synchrotron,
Hamburg, Germany
M. Aldaya Martin, T. Arndt, C. Asawatangtrakuldee, K. Beernaert, O. Behnke, U.
Behrens, A. Bermúdez Martínez, A.A. Bin Anuar, K. Borras16, V. Botta, A.
Campbell, P. Connor, C. Contreras-Campana, F. Costanza, C. Diez Pardos, G.
Eckerlin, D. Eckstein, T. Eichhorn, E. Eren, E. Gallo17, J. Garay Garcia, A.
Geiser, J.M. Grados Luyando, A. Grohsjean, P. Gunnellini, M. Guthoff, A. Harb,
J. Hauk, M. Hempel18, H. Jung, M. Kasemann, J. Keaveney, C. Kleinwort, I.
Korol, D. Krücker, W. Lange, A. Lelek, T. Lenz, J. Leonard, K. Lipka, W.
Lohmann18, R. Mankel, I.-A. Melzer-Pellmann, A.B. Meyer, G. Mittag, J. Mnich,
A. Mussgiller, E. Ntomari, D. Pitzl, A. Raspereza, M. Savitskyi, P. Saxena, R.
Shevchenko, S. Spannagel, N. Stefaniuk, G.P. Van Onsem, R. Walsh, Y. Wen, K.
Wichmann, C. Wissing, O. Zenaiev University of Hamburg, Hamburg, Germany
R. Aggleton, S. Bein, V. Blobel, M. Centis Vignali, T. Dreyer, E. Garutti, D.
Gonzalez, J. Haller, A. Hinzmann, M. Hoffmann, A. Karavdina, R. Klanner, R.
Kogler, N. Kovalchuk, S. Kurz, T. Lapsien, D. Marconi, M. Meyer, M. Niedziela,
D. Nowatschin, F. Pantaleo15, T. Peiffer, A. Perieanu, C. Scharf, P. Schleper,
A. Schmidt, S. Schumann, J. Schwandt, J. Sonneveld, H. Stadie, G. Steinbrück,
F.M. Stober, M. Stöver, H. Tholen, D. Troendle, E. Usai, A. Vanhoefer, B.
Vormwald Institut für Experimentelle Kernphysik, Karlsruhe, Germany
M. Akbiyik, C. Barth, M. Baselga, S. Baur, E. Butz, R. Caspart, T. Chwalek, F.
Colombo, W. De Boer, A. Dierlamm, N. Faltermann, B. Freund, R. Friese, M.
Giffels, M.A. Harrendorf, F. Hartmann15, S.M. Heindl, U. Husemann, F.
Kassel15, S. Kudella, H. Mildner, M.U. Mozer, Th. Müller, M. Plagge, G. Quast,
K. Rabbertz, M. Schröder, I. Shvetsov, G. Sieber, H.J. Simonis, R. Ulrich, S.
Wayand, M. Weber, T. Weiler, S. Williamson, C. Wöhrmann, R. Wolf Institute of
Nuclear and Particle Physics (INPP), NCSR Demokritos, Aghia Paraskevi, Greece
G. Anagnostou, G. Daskalakis, T. Geralis, A. Kyriakis, D. Loukas, I. Topsis-
Giotis National and Kapodistrian University of Athens, Athens, Greece
G. Karathanasis, S. Kesisoglou, A. Panagiotou, N. Saoulidou National Technical
University of Athens, Athens, Greece
K. Kousouris University of Ioánnina, Ioánnina, Greece
I. Evangelou, C. Foudas, P. Gianneios, P. Katsoulis, P. Kokkas, S. Mallios, N.
Manthos, I. Papadopoulos, E. Paradas, J. Strologas, F.A. Triantis, D.
Tsitsonis MTA-ELTE Lendület CMS Particle and Nuclear Physics Group, Eötvös
Loránd University, Budapest, Hungary
M. Csanad, N. Filipovic, G. Pasztor, O. Surányi, G.I. Veres19 Wigner Research
Centre for Physics, Budapest, Hungary
G. Bencze, C. Hajdu, D. Horvath20, Á. Hunyadi, F. Sikler, V. Veszpremi
Institute of Nuclear Research ATOMKI, Debrecen, Hungary
N. Beni, S. Czellar, J. Karancsi21, A. Makovec, J. Molnar, Z. Szillasi
Institute of Physics, University of Debrecen, Debrecen, Hungary
M. Bartók19, P. Raics, Z.L. Trocsanyi, B. Ujvari Indian Institute of Science
(IISc), Bangalore, India
S. Choudhury, J.R. Komaragiri National Institute of Science Education and
Research, Bhubaneswar, India
S. Bahinipati22, S. Bhowmik, P. Mal, K. Mandal, A. Nayak23, D.K. Sahoo22, N.
Sahoo, S.K. Swain Panjab University, Chandigarh, India
S. Bansal, S.B. Beri, V. Bhatnagar, R. Chawla, N. Dhingra, A.K. Kalsi, A.
Kaur, M. Kaur, S. Kaur, R. Kumar, P. Kumari, A. Mehta, J.B. Singh, G. Walia
University of Delhi, Delhi, India
Ashok Kumar, Aashaq Shah, A. Bhardwaj, S. Chauhan, B.C. Choudhary, R.B. Garg,
S. Keshri, A. Kumar, S. Malhotra, M. Naimuddin, K. Ranjan, R. Sharma Saha
Institute of Nuclear Physics, HBNI, Kolkata, India
R. Bhardwaj, R. Bhattacharya, S. Bhattacharya, U. Bhawandeep, S. Dey, S. Dutt,
S. Dutta, S. Ghosh, N. Majumdar, A. Modak, K. Mondal, S. Mukhopadhyay, S.
Nandan, A. Purohit, A. Roy, S. Roy Chowdhury, S. Sarkar, M. Sharan, S. Thakur
Indian Institute of Technology Madras, Madras, India
P.K. Behera Bhabha Atomic Research Centre, Mumbai, India
R. Chudasama, D. Dutta, V. Jha, V. Kumar, A.K. Mohanty15, P.K. Netrakanti,
L.M. Pant, P. Shukla, A. Topkar Tata Institute of Fundamental Research-A,
Mumbai, India
T. Aziz, S. Dugad, B. Mahakud, S. Mitra, G.B. Mohanty, N. Sur, B. Sutar Tata
Institute of Fundamental Research-B, Mumbai, India
S. Banerjee, S. Bhattacharya, S. Chatterjee, P. Das, M. Guchait, Sa. Jain, S.
Kumar, M. Maity24, G. Majumder, K. Mazumdar, T. Sarkar24, N. Wickramage25
Indian Institute of Science Education and Research (IISER), Pune, India
S. Chauhan, S. Dube, V. Hegde, A. Kapoor, K. Kothekar, S. Pandey, A. Rane, S.
Sharma Institute for Research in Fundamental Sciences (IPM), Tehran, Iran
S. Chenarani26, E. Eskandari Tadavani, S.M. Etesami26, M. Khakzad, M.
Mohammadi Najafabadi, M. Naseri, S. Paktinat Mehdiabadi27, F. Rezaei
Hosseinabadi, B. Safarzadeh28, M. Zeinali 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, C. Calabriaa,b, A. Colaleoa, D. Creanzaa,c, L. Cristellaa,b,
N. De Filippisa,c, M. De Palmaa,b, F. Erricoa,b, L. Fiorea, G. Iasellia,c, S.
Lezkia,b, G. Maggia,c, M. Maggia, G. Minielloa,b, S. Mya,b, S. Nuzzoa,b, A.
Pompilia,b, G. Pugliesea,c, R. Radognaa, A. Ranieria, G. Selvaggia,b, A.
Sharmaa, L. Silvestrisa,15, 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,
S.S. Chhibraa, G. Codispotia,b, M. Cuffiania,b, G.M. Dallavallea, F. Fabbria,
A. Fanfania,b, D. Fasanellaa,b, P. Giacomellia, C. Grandia, L. Guiduccia,b, S.
Marcellinia, G. Masettia, A. Montanaria, F.L. Navarriaa,b, A. Perrottaa, 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, S. Costaa,b, A. Di Mattiaa, F. Giordanoa,b, R. Potenzaa,b, A.
Tricomia,b, C. Tuvea,b INFN Sezione di Firenze a, Università di Firenze b,
Firenze, Italy
G. Barbaglia, K. Chatterjeea,b, V. Ciullia,b, C. Civininia, R.
D’Alessandroa,b, E. Focardia,b, P. Lenzia,b, M. Meschinia, S. Paolettia, L.
Russoa,29, G. Sguazzonia, D. Stroma, L. Viliania,b,15 INFN Laboratori
Nazionali di Frascati, Frascati, Italy
L. Benussi, S. Bianco, F. Fabbri, D. Piccolo, F. Primavera15 INFN Sezione di
Genova a, Università di Genova b, Genova, Italy
V. Calvellia,b, F. Ferroa, E. Robuttia, S. Tosia,b INFN Sezione di Milano-
Bicocca a, Università di Milano-Bicocca b, Milano, Italy
A. Benagliaa, A. Beschib, L. Brianzaa,b, F. Brivioa,b, V. Cirioloa,b,15, M.E.
Dinardoa,b, S. Fiorendia,b, S. Gennaia, A. Ghezzia,b, P. Govonia,b, M.
Malbertia,b, S. Malvezzia, R.A. Manzonia,b, D. Menascea, L. Moronia, M.
Paganonia,b, K. Pauwelsa,b, D. Pedrinia, S. Pigazzinia,b,30, S. Ragazzia,b, T.
Tabarelli de Fatisa,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, S. Di Guidaa,d,15, F. Fabozzia,c, F. Fiengaa,b,
A.O.M. Iorioa,b, W.A. Khana, L. Listaa, S. Meolaa,d,15, P. Paoluccia,15, C.
Sciaccaa,b, F. Thyssena INFN Sezione di Padova a, Università di Padova b,
Padova, Italy, Università di Trento c, Trento, Italy
P. Azzia, N. Bacchettaa, L. Benatoa,b, D. Biselloa,b, A. Bolettia,b, A.
Carvalho Antunes De Oliveiraa,b, P. Checchiaa, M. Dall’Ossoa,b, P. De Castro
Manzanoa, T. Dorigoa, U. Dossellia, F. Gasparinia,b, A. Gozzelinoa, S.
Lacapraraa, P. Lujan, M. Margonia,b, A.T. Meneguzzoa,b, D. Pantanoa, N.
Pozzobona,b, P. Ronchesea,b, R. Rossina,b, E. Torassaa, S. Venturaa, M.
Zanettia,b, P. Zottoa,b, G. Zumerlea,b INFN Sezione di Pavia a, Università di
Pavia b, Pavia, Italy
A. Braghieria, A. Magnania, P. Montagnaa,b, S.P. Rattia,b, V. Rea, M.
Ressegottia,b, C. Riccardia,b, P. Salvinia, I. Vaia,b, P. Vituloa,b INFN
Sezione di Perugia a, Università di Perugia b, Perugia, Italy
L. Alunni Solestizia,b, M. Biasinia,b, G.M. Bileia, C. Cecchia,b, D.
Ciangottinia,b, L. Fanòa,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,15, G. Bagliesia, T. Boccalia, L. Borrello, R.
Castaldia, M.A. Cioccia,b, R. Dell’Orsoa, G. Fedia, L. Gianninia,c, A.
Giassia, M.T. Grippoa,29, F. Ligabuea,c, T. Lomtadzea, E. Mancaa,c, G.
Mandorlia,c, A. Messineoa,b, F. Pallaa, A. Rizzia,b, A. Savoy-Navarroa,31, P.
Spagnoloa, R. Tenchinia, G. Tonellia,b, A. Venturia, P.G. Verdinia INFN
Sezione di Roma a, Sapienza Università di Roma b, Rome, Italy
L. Baronea,b, F. Cavallaria, M. Cipriania,b, N. Dacia, D. Del Rea,b,15, E. Di
Marcoa,b, M. Diemoza, S. Gellia,b, E. Longoa,b, F. Margarolia,b, B.
Marzocchia,b, P. Meridiania, G. Organtinia,b, R. Paramattia,b, F. Preiatoa,b,
S. Rahatloua,b, C. Rovellia, F. Santanastasioa,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, C. Biinoa, N. Cartigliaa, F. Cennaa,b, M. Costaa,b, R.
Covarellia,b, A. Deganoa,b, N. Demariaa, B. Kiania,b, C. Mariottia, S.
Masellia, E. Migliorea,b, V. Monacoa,b, E. Monteila,b, M. Montenoa, M.M.
Obertinoa,b, L. Pachera,b, N. Pastronea, M. Pelliccionia, G.L. Pinna
Angionia,b, F. Raveraa,b, A. Romeroa,b, M. Ruspaa,c, R. Sacchia,b, K.
Shchelinaa,b, V. Solaa, A. Solanoa,b, A. Staianoa, P. Traczyka,b INFN Sezione
di Trieste a, Università di Trieste b, Trieste, Italy
S. Belfortea, M. Casarsaa, F. Cossuttia, G. Della Riccaa,b, A. Zanettia
Kyungpook National University, Daegu, Korea
D.H. Kim, G.N. Kim, M.S. Kim, J. Lee, S. Lee, S.W. Lee, C.S. Moon, Y.D. Oh, S.
Sekmen, D.C. Son, Y.C. Yang Chonbuk National University, Jeonju, Korea
A. Lee Chonnam National University, Institute for Universe and Elementary
Particles, Kwangju, Korea
H. Kim, D.H. Moon, G. Oh Hanyang University, Seoul, Korea
J.A. Brochero Cifuentes, J. Goh, T.J. Kim Korea University, Seoul, Korea
S. Cho, S. Choi, Y. Go, D. Gyun, S. Ha, B. Hong, Y. Jo, Y. Kim, K. Lee, K.S.
Lee, S. Lee, J. Lim, S.K. Park, Y. Roh Seoul National University, Seoul, Korea
J. Almond, J. Kim, J.S. Kim, H. Lee, K. Lee, K. Nam, S.B. Oh, B.C. Radburn-
Smith, S.h. Seo, U.K. Yang, H.D. Yoo, G.B. Yu University of Seoul, Seoul,
Korea
H. Kim, J.H. Kim, J.S.H. Lee, I.C. Park Sungkyunkwan University, Suwon, Korea
Y. Choi, C. Hwang, J. Lee, I. Yu Vilnius University, Vilnius, Lithuania
V. Dudenas, A. Juodagalvis, J. Vaitkus National Centre for Particle Physics,
Universiti Malaya, Kuala Lumpur, Malaysia
I. Ahmed, Z.A. Ibrahim, M.A.B. Md Ali32, F. Mohamad Idris33, W.A.T. Wan
Abdullah, M.N. Yusli, Z. Zolkapli Centro de Investigacion y de Estudios
Avanzados del IPN, Mexico City, Mexico
Reyes-Almanza, R, Ramirez-Sanchez, G., Duran-Osuna, M. C., H. Castilla-Valdez,
E. De La Cruz-Burelo, I. Heredia-De La Cruz34, Rabadan-Trejo, R. I., R. Lopez-
Fernandez, J. Mejia Guisao, A. Sanchez-Hernandez Universidad Iberoamericana,
Mexico City, Mexico
S. Carrillo Moreno, C. Oropeza Barrera, 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 Auckland, Auckland, New Zealand
D. Krofcheck University of Canterbury, Christchurch, New Zealand
P.H. Butler National Centre for Physics, Quaid-I-Azam University, Islamabad,
Pakistan
A. Ahmad, M. Ahmad, Q. Hassan, H.R. Hoorani, A. Saddique, M.A. Shah, M.
Shoaib, M. Waqas National Centre for Nuclear Research, Swierk, Poland
H. Bialkowska, M. Bluj, B. Boimska, T. Frueboes, M. Górski, M. Kazana, K.
Nawrocki, M. Szleper, P. Zalewski Institute of Experimental Physics, Faculty
of Physics, University of Warsaw, Warsaw, Poland
K. Bunkowski, A. Byszuk35, K. Doroba, A. Kalinowski, M. Konecki, J.
Krolikowski, M. Misiura, M. Olszewski, A. Pyskir, M. Walczak Laboratório de
Instrumentação e Física Experimental de Partículas, Lisboa, Portugal
P. Bargassa, C. Beirão Da Cruz E Silva, A. Di Francesco, P. Faccioli, B.
Galinhas, M. Gallinaro, J. Hollar, N. Leonardo, L. Lloret Iglesias, M.V.
Nemallapudi, J. Seixas, G. Strong, O. Toldaiev, D. Vadruccio, J. Varela Joint
Institute for Nuclear Research, Dubna, Russia
S. Afanasiev, P. Bunin, M. Gavrilenko, I. Golutvin, I. Gorbunov, A. Kamenev,
V. Karjavin, A. Lanev, A. Malakhov, V. Matveev36,37, V. Palichik, V.
Perelygin, S. Shmatov, S. Shulha, N. Skatchkov, V. Smirnov, N. Voytishin, A.
Zarubin Petersburg Nuclear Physics Institute, Gatchina (St. Petersburg),
Russia
Y. Ivanov, V. Kim38, E. Kuznetsova39, P. Levchenko, V. Murzin, V. Oreshkin, I.
Smirnov, D. Sosnov, V. Sulimov, L. Uvarov, S. Vavilov, 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, Moscow, Russia
V. Epshteyn, V. Gavrilov, N. Lychkovskaya, 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, A. Bylinkin37 National Research Nuclear University ’Moscow
Engineering Physics Institute’ (MEPhI), Moscow, Russia
M. Chadeeva40, O. Markin, P. Parygin, D. Philippov, S. Polikarpov, V. Rusinov
P.N. Lebedev Physical Institute, Moscow, Russia
V. Andreev, M. Azarkin37, I. Dremin37, M. Kirakosyan37, A. Terkulov Skobeltsyn
Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow,
Russia
A. Baskakov, A. Belyaev, E. Boos, V. Bunichev, M. Dubinin41, L. Dudko, A.
Gribushin, V. Klyukhin, O. Kodolova, I. Lokhtin, I. Miagkov, S. Obraztsov, S.
Petrushanko, V. Savrin, A. Snigirev Novosibirsk State University (NSU),
Novosibirsk, Russia
V. Blinov42, Y.Skovpen42, D. Shtol42 State Research Center of Russian
Federation, Institute for High Energy Physics, Protvino, Russia
I. Azhgirey, I. Bayshev, S. Bitioukov, D. Elumakhov, A. Godizov, V. Kachanov,
A. Kalinin, D. Konstantinov, P. Mandrik, V. Petrov, R. Ryutin, A. Sobol, S.
Troshin, N. Tyurin, A. Uzunian, A. Volkov University of Belgrade, Faculty of
Physics and Vinca Institute of Nuclear Sciences, Belgrade, Serbia
P. Adzic43, P. Cirkovic, D. Devetak, M. Dordevic, J. Milosevic, V. Rekovic
Centro de Investigaciones Energéticas Medioambientales y Tecnológicas
(CIEMAT), Madrid, Spain
J. Alcaraz Maestre, I. Bachiller, M. Barrio Luna, M. Cerrada, N. Colino, B. De
La Cruz, A. Delgado Peris, A. Escalante Del Valle, C. Fernandez Bedoya, J.P.
Fernández Ramos, J. Flix, M.C. Fouz, O. Gonzalez Lopez, S. Goy Lopez, J.M.
Hernandez, M.I. Josa, D. Moran, A. Pérez-Calero Yzquierdo, J. Puerta Pelayo,
A. Quintario Olmeda, I. Redondo, L. Romero, M.S. Soares, A. Álvarez Fernández
Universidad Autónoma de Madrid, Madrid, Spain
C. Albajar, J.F. de Trocóniz, M. Missiroli Universidad de Oviedo, Oviedo,
Spain
J. Cuevas, C. Erice, J. Fernandez Menendez, I. Gonzalez Caballero, J.R.
González Fernández, E. Palencia Cortezon, S. Sanchez Cruz, P. Vischia, J.M.
Vizan Garcia Instituto de Física de Cantabria (IFCA), CSIC-Universidad de
Cantabria, Santander, Spain
I.J. Cabrillo, A. Calderon, B. Chazin Quero, E. Curras, J. Duarte Campderros,
M. Fernandez, J. Garcia-Ferrero, G. Gomez, A. Lopez Virto, J. Marco, C.
Martinez Rivero, P. Martinez Ruiz del Arbol, F. Matorras, J. Piedra Gomez, T.
Rodrigo, A. Ruiz-Jimeno, L. Scodellaro, N. Trevisani, I. Vila, R. Vilar
Cortabitarte CERN, European Organization for Nuclear Research, Geneva,
Switzerland
D. Abbaneo, B. Akgun, E. Auffray, P. Baillon, A.H. Ball, D. Barney, J.
Bendavid, M. Bianco, P. Bloch, A. Bocci, C. Botta, T. Camporesi, R. Castello,
M. Cepeda, G. Cerminara, E. Chapon, Y. Chen, D. d’Enterria, A. Dabrowski, V.
Daponte, A. David, M. De Gruttola, A. De Roeck, N. Deelen, M. Dobson, T. du
Pree, M. Dünser, N. Dupont, A. Elliott-Peisert, P. Everaerts, F. Fallavollita,
G. Franzoni, J. Fulcher, W. Funk, D. Gigi, A. Gilbert, K. Gill, F. Glege, D.
Gulhan, P. Harris, J. Hegeman, V. Innocente, A. Jafari, P. Janot, O.
Karacheban18, J. Kieseler, V. Knünz, A. Kornmayer, M.J. Kortelainen, M.
Krammer1, C. Lange, P. Lecoq, C. Lourenço, M.T. Lucchini, L. Malgeri, M.
Mannelli, A. Martelli, F. Meijers, J.A. Merlin, S. Mersi, E. Meschi, P.
Milenovic44, F. Moortgat, M. Mulders, H. Neugebauer, J. Ngadiuba, S.
Orfanelli, L. Orsini, L. Pape, E. Perez, M. Peruzzi, A. Petrilli, G.
Petrucciani, A. Pfeiffer, M. Pierini, D. Rabady, A. Racz, T. Reis, G.
Rolandi45, M. Rovere, H. Sakulin, C. Schäfer, C. Schwick, M. Seidel, M.
Selvaggi, A. Sharma, P. Silva, P. Sphicas46, A. Stakia, J. Steggemann, M.
Stoye, M. Tosi, D. Treille, A. Triossi, A. Tsirou, V. Veckalns47, M. Verweij,
W.D. Zeuner Paul Scherrer Institut, Villigen, Switzerland
W. Bertl${}^{\textrm{\textdagger}}$, L. Caminada48, K. Deiters, W. Erdmann, R.
Horisberger, Q. Ingram, H.C. Kaestli, D. Kotlinski, U. Langenegger, T. Rohe,
S.A. Wiederkehr Institute for Particle Physics and Astrophysics (IPA), Zurich,
Switzerland
M. Backhaus, L. Bäni, P. Berger, L. Bianchini, B. Casal, G. Dissertori, M.
Dittmar, M. Donegà, C. Dorfer, C. Grab, C. Heidegger, D. Hits, J. Hoss, G.
Kasieczka, T. Klijnsma, W. Lustermann, B. Mangano, M. Marionneau, M.T.
Meinhard, D. Meister, F. Micheli, P. Musella, F. Nessi-Tedaldi, F. Pandolfi,
J. Pata, F. Pauss, G. Perrin, L. Perrozzi, M. Quittnat, M. Reichmann, D.A.
Sanz Becerra, M. Schönenberger, L. Shchutska, V.R. Tavolaro, K. Theofilatos,
M.L. Vesterbacka Olsson, R. Wallny, D.H. Zhu Universität Zürich, Zurich,
Switzerland
T.K. Aarrestad, C. Amsler49, M.F. Canelli, A. De Cosa, R. Del Burgo, S.
Donato, C. Galloni, T. Hreus, B. Kilminster, D. Pinna, G. Rauco, P. Robmann,
D. Salerno, K. Schweiger, C. Seitz, Y. Takahashi, A. Zucchetta National
Central University, Chung-Li, Taiwan
V. Candelise, Y.H. Chang, K.y. Cheng, T.H. Doan, Sh. Jain, R. Khurana, C.M.
Kuo, W. Lin, A. Pozdnyakov, S.S. Yu National Taiwan University (NTU), Taipei,
Taiwan
Arun Kumar, P. Chang, Y. Chao, K.F. Chen, P.H. Chen, F. Fiori, W.-S. Hou, Y.
Hsiung, Y.F. Liu, R.-S. Lu, E. Paganis, A. Psallidas, A. Steen, J.f. Tsai
Chulalongkorn University, Faculty of Science, Department of Physics, Bangkok,
Thailand
B. Asavapibhop, K. Kovitanggoon, G. Singh, N. Srimanobhas Çukurova University,
Physics Department, Science and Art Faculty, Adana, Turkey
M.N. Bakirci50, A. Bat, F. Boran, S. Damarseckin, Z.S. Demiroglu, C. Dozen, E.
Eskut, S. Girgis, G. Gokbulut, Y. Guler, I. Hos51, E.E. Kangal52, O. Kara, A.
Kayis Topaksu, U. Kiminsu, M. Oglakci, G. Onengut53, K. Ozdemir54, A. Polatoz,
U.G. Tok, H. Topakli50, S. Turkcapar, I.S. Zorbakir, C. Zorbilmez Middle East
Technical University, Physics Department, Ankara, Turkey
B. Bilin, G. Karapinar55, K. Ocalan56, M. Yalvac, M. Zeyrek Bogazici
University, Istanbul, Turkey
E. Gülmez, M. Kaya57, O. Kaya58, S. Tekten, E.A. Yetkin59 Istanbul Technical
University, Istanbul, Turkey
M.N. Agaras, S. Atay, A. Cakir, K. Cankocak, I. Köseoglu 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
F. Ball, L. Beck, J.J. Brooke, D. Burns, E. Clement, D. Cussans, O. Davignon,
H. Flacher, J. Goldstein, G.P. Heath, H.F. Heath, L. Kreczko, D.M. Newbold60,
S. Paramesvaran, T. Sakuma, S. Seif El Nasr-storey, D. Smith, V.J. Smith
Rutherford Appleton Laboratory, Didcot, United Kingdom
K.W. Bell, A. Belyaev61, C. Brew, R.M. Brown, L. Calligaris, D. Cieri, D.J.A.
Cockerill, J.A. Coughlan, K. Harder, S. Harper, J. Linacre, E. Olaiya, D.
Petyt, C.H. Shepherd-Themistocleous, A. Thea, I.R. Tomalin, T. Williams
Imperial College, London, United Kingdom
G. Auzinger, R. Bainbridge, J. Borg, S. Breeze, O. Buchmuller, A. Bundock, S.
Casasso, M. Citron, D. Colling, L. Corpe, P. Dauncey, G. Davies, A. De Wit, M.
Della Negra, R. Di Maria, A. Elwood, Y. Haddad, G. Hall, G. Iles, T. James, R.
Lane, C. Laner, L. Lyons, A.-M. Magnan, S. Malik, L. Mastrolorenzo, T.
Matsushita, J. Nash, A. Nikitenko7, V. Palladino, M. Pesaresi, D.M. Raymond,
A. Richards, A. Rose, E. Scott, C. Seez, A. Shtipliyski, S. Summers, A.
Tapper, K. Uchida, M. Vazquez Acosta62, T. Virdee15, N. Wardle, D.
Winterbottom, J. Wright, S.C. Zenz Brunel University, Uxbridge, United Kingdom
J.E. Cole, P.R. Hobson, A. Khan, P. Kyberd, I.D. Reid, L. Teodorescu, S. Zahid
Baylor University, Waco, USA
A. Borzou, K. Call, J. Dittmann, K. Hatakeyama, H. Liu, N. Pastika, C. Smith
Catholic University of America, Washington DC, USA
R. Bartek, A. Dominguez The University of Alabama, Tuscaloosa, USA
A. Buccilli, S.I. Cooper, C. Henderson, P. Rumerio, C. West Boston University,
Boston, USA
D. Arcaro, A. Avetisyan, T. Bose, D. Gastler, D. Rankin, C. Richardson, J.
Rohlf, L. Sulak, D. Zou Brown University, Providence, USA
G. Benelli, D. Cutts, A. Garabedian, M. Hadley, J. Hakala, U. Heintz, J.M.
Hogan, K.H.M. Kwok, E. Laird, G. Landsberg, J. Lee, Z. Mao, M. Narain, J.
Pazzini, S. Piperov, S. Sagir, R. Syarif, D. Yu University of California,
Davis, Davis, USA
R. Band, C. Brainerd, D. Burns, M. Calderon De La Barca Sanchez, M. Chertok,
J. Conway, R. Conway, P.T. Cox, R. Erbacher, C. Flores, G. Funk, W. Ko, R.
Lander, C. Mclean, M. Mulhearn, D. Pellett, J. Pilot, S. Shalhout, M. Shi, J.
Smith, D. Stolp, K. Tos, M. Tripathi, Z. Wang University of California, Los
Angeles, USA
M. Bachtis, C. Bravo, R. Cousins, A. Dasgupta, A. Florent, J. Hauser, M.
Ignatenko, N. Mccoll, S. Regnard, D. Saltzberg, C. Schnaible, V. Valuev
University of California, Riverside, Riverside, USA
E. Bouvier, K. Burt, R. Clare, J. Ellison, J.W. Gary, S.M.A. Ghiasi Shirazi,
G. Hanson, J. Heilman, G. Karapostoli, E. Kennedy, F. Lacroix, O.R. Long, M.
Olmedo Negrete, M.I. Paneva, W. Si, L. Wang, H. Wei, S. Wimpenny, B. R. Yates
University of California, San Diego, La Jolla, USA
J.G. Branson, S. Cittolin, M. Derdzinski, R. Gerosa, D. Gilbert, B. Hashemi,
A. Holzner, D. Klein, G. Kole, V. Krutelyov, J. Letts, I. Macneill, M.
Masciovecchio, D. Olivito, S. Padhi, M. Pieri, M. Sani, V. Sharma, S. Simon,
M. Tadel, A. Vartak, S. Wasserbaech63, J. Wood, F. Würthwein, A. Yagil, G.
Zevi Della Porta University of California, Santa Barbara - Department of
Physics, Santa Barbara, USA
N. Amin, R. Bhandari, J. Bradmiller-Feld, C. Campagnari, A. Dishaw, V. Dutta,
M. Franco Sevilla, F. Golf, L. Gouskos, R. Heller, J. Incandela, A. Ovcharova,
H. Qu, J. Richman, D. Stuart, I. Suarez, J. Yoo California Institute of
Technology, Pasadena, USA
D. Anderson, A. Bornheim, J.M. Lawhorn, H.B. Newman, T. Nguyen, C. Pena, M.
Spiropulu, J.R. Vlimant, S. Xie, Z. Zhang, R.Y. Zhu Carnegie Mellon
University, Pittsburgh, USA
M.B. Andrews, T. Ferguson, T. Mudholkar, M. Paulini, J. Russ, M. Sun, H.
Vogel, I. Vorobiev, M. Weinberg University of Colorado Boulder, Boulder, USA
J.P. Cumalat, W.T. Ford, F. Jensen, A. Johnson, M. Krohn, S. Leontsinis, T.
Mulholland, K. Stenson, S.R. Wagner Cornell University, Ithaca, USA
J. Alexander, J. Chaves, J. Chu, S. Dittmer, K. Mcdermott, N. Mirman, J.R.
Patterson, D. Quach, A. Rinkevicius, A. Ryd, L. Skinnari, L. Soffi, S.M. Tan,
Z. Tao, J. Thom, J. Tucker, 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, J. Berryhill, P.C. Bhat, G.
Bolla${}^{\textrm{\textdagger}}$, K. Burkett, J.N. Butler, A. Canepa, G.B.
Cerati, H.W.K. Cheung, F. Chlebana, M. Cremonesi, J. Duarte, V.D. Elvira, J.
Freeman, Z. Gecse, E. Gottschalk, L. Gray, D. Green, S. Grünendahl, O.
Gutsche, R.M. Harris, S. Hasegawa, J. Hirschauer, Z. Hu, B. Jayatilaka, S.
Jindariani, M. Johnson, U. Joshi, B. Klima, B. Kreis, S. Lammel, D. Lincoln,
R. Lipton, M. Liu, T. Liu, R. Lopes De Sá, J. Lykken, K. Maeshima, N. Magini,
J.M. Marraffino, D. Mason, P. McBride, P. Merkel, S. Mrenna, S. Nahn, V.
O’Dell, K. Pedro, O. Prokofyev, G. Rakness, L. Ristori, B. Schneider, E.
Sexton-Kennedy, A. Soha, W.J. Spalding, L. Spiegel, S. Stoynev, J. Strait, N.
Strobbe, L. Taylor, S. Tkaczyk, N.V. Tran, L. Uplegger, E.W. Vaandering, C.
Vernieri, M. Verzocchi, R. Vidal, M. Wang, H.A. Weber, A. Whitbeck University
of Florida, Gainesville, USA
D. Acosta, P. Avery, P. Bortignon, D. Bourilkov, A. Brinkerhoff, A. Carnes, M.
Carver, D. Curry, R.D. Field, I.K. Furic, S.V. Gleyzer, B.M. Joshi, J.
Konigsberg, A. Korytov, K. Kotov, P. Ma, K. Matchev, H. Mei, G. Mitselmakher,
K. Shi, D. Sperka, N. Terentyev, L. Thomas, J. Wang, S. Wang, J. Yelton
Florida International University, Miami, USA
Y.R. Joshi, S. Linn, P. Markowitz, J.L. Rodriguez Florida State University,
Tallahassee, USA
A. Ackert, T. Adams, A. Askew, S. Hagopian, V. Hagopian, K.F. Johnson, T.
Kolberg, G. Martinez, T. Perry, H. Prosper, A. Saha, A. Santra, V. Sharma, R.
Yohay Florida Institute of Technology, Melbourne, USA
M.M. Baarmand, V. Bhopatkar, S. Colafranceschi, M. Hohlmann, D. Noonan, T.
Roy, F. Yumiceva University of Illinois at Chicago (UIC), Chicago, USA
M.R. Adams, L. Apanasevich, D. Berry, R.R. Betts, R. Cavanaugh, X. Chen, O.
Evdokimov, C.E. Gerber, D.A. Hangal, D.J. Hofman, K. Jung, J. Kamin, I.D.
Sandoval Gonzalez, M.B. Tonjes, H. Trauger, N. Varelas, H. Wang, Z. Wu, J.
Zhang The University of Iowa, Iowa City, USA
B. Bilki64, W. Clarida, K. Dilsiz65, S. Durgut, R.P. Gandrajula, M.
Haytmyradov, V. Khristenko, J.-P. Merlo, H. Mermerkaya66, A. Mestvirishvili,
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E. Tiras, J. Wetzel, K. Yi Johns Hopkins University, Baltimore, USA
B. Blumenfeld, A. Cocoros, N. Eminizer, D. Fehling, L. Feng, A.V. Gritsan, P.
Maksimovic, C. Mantilla, J. Roskes, U. Sarica, M. Swartz, M. Xiao, C. You The
University of Kansas, Lawrence, USA
A. Al-bataineh, P. Baringer, A. Bean, S. Boren, J. Bowen, J. Castle, S.
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Sanders, E. Schmitz, J.D. Tapia Takaki, Q. Wang Kansas State University,
Manhattan, USA
A. Ivanov, K. Kaadze, Y. Maravin, A. Mohammadi, L.K. Saini, N. Skhirtladze, S.
Toda Lawrence Livermore National Laboratory, Livermore, USA
F. Rebassoo, D. Wright University of Maryland, College Park, USA
C. Anelli, A. Baden, O. Baron, A. Belloni, S.C. Eno, Y. Feng, C. Ferraioli,
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Ricci-Tam, Y.H. Shin, A. Skuja, S.C. Tonwar Massachusetts Institute of
Technology, Cambridge, USA
D. Abercrombie, B. Allen, V. Azzolini, R. Barbieri, A. Baty, R. Bi, S. Brandt,
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Wyslouch University of Minnesota, Minneapolis, USA
A.C. Benvenuti, R.M. Chatterjee, A. Evans, P. Hansen, J. Hiltbrand, S.
Kalafut, Y. Kubota, Z. Lesko, J. Mans, S. Nourbakhsh, N. Ruckstuhl, R. Rusack,
J. Turkewitz, M.A. Wadud University of Mississippi, Oxford, USA
J.G. Acosta, S. Oliveros University of Nebraska-Lincoln, Lincoln, USA
E. Avdeeva, K. Bloom, D.R. Claes, C. Fangmeier, R. Gonzalez Suarez, R.
Kamalieddin, I. Kravchenko, J. Monroy, J.E. Siado, G.R. Snow, B. Stieger State
University of New York at Buffalo, Buffalo, USA
J. Dolen, A. Godshalk, C. Harrington, I. Iashvili, D. Nguyen, A. Parker, S.
Rappoccio, B. Roozbahani Northeastern University, Boston, USA
G. Alverson, E. Barberis, C. Freer, A. Hortiangtham, A. Massironi, D.M. Morse,
T. Orimoto, R. Teixeira De Lima, D. Trocino, T. Wamorkar, B. Wang, A.
Wisecarver, D. Wood Northwestern University, Evanston, USA
S. Bhattacharya, O. Charaf, K.A. Hahn, N. Mucia, N. Odell, M.H. Schmitt, K.
Sung, M. Trovato, M. Velasco University of Notre Dame, Notre Dame, USA
R. Bucci, N. Dev, M. Hildreth, K. Hurtado Anampa, C. Jessop, D.J. Karmgard, N.
Kellams, K. Lannon, W. Li, N. Loukas, N. Marinelli, F. Meng, C. Mueller, Y.
Musienko36, M. Planer, A. Reinsvold, R. Ruchti, P. Siddireddy, G. Smith, S.
Taroni, M. Wayne, A. Wightman, M. Wolf, A. Woodard The Ohio State University,
Columbus, USA
J. Alimena, L. Antonelli, B. Bylsma, L.S. Durkin, S. Flowers, B. Francis, A.
Hart, C. Hill, W. Ji, B. Liu, W. Luo, B.L. Winer, H.W. Wulsin Princeton
University, Princeton, USA
S. Cooperstein, O. Driga, P. Elmer, J. Hardenbrook, P. Hebda, S. Higginbotham,
A. Kalogeropoulos, D. Lange, 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, S. Das, S. Folgueras, L. Gutay, M.K. Jha, M. Jones,
A.W. Jung, A. Khatiwada, D.H. Miller, N. Neumeister, C.C. Peng, H. Qiu, J.F.
Schulte, J. Sun, F. Wang, R. Xiao, W. Xie Purdue University Northwest,
Hammond, USA
T. Cheng, N. Parashar, J. Stupak Rice University, Houston, USA
Z. Chen, K.M. Ecklund, S. Freed, F.J.M. Geurts, M. Guilbaud, M. Kilpatrick, W.
Li, B. Michlin, B.P. Padley, J. Roberts, J. Rorie, W. Shi, Z. Tu, J. Zabel, A.
Zhang University of Rochester, Rochester, USA
A. Bodek, P. de Barbaro, R. Demina, Y.t. Duh, T. Ferbel, M. Galanti, A.
Garcia-Bellido, J. Han, O. Hindrichs, A. Khukhunaishvili, K.H. Lo, P. Tan, M.
Verzetti The Rockefeller University, New York, USA
R. Ciesielski, K. Goulianos, C. Mesropian Rutgers, The State University of New
Jersey, Piscataway, USA
A. Agapitos, J.P. Chou, Y. Gershtein, T.A. Gómez Espinosa, E. Halkiadakis, M.
Heindl, E. Hughes, S. Kaplan, R. Kunnawalkam Elayavalli, S. Kyriacou, A. Lath,
R. Montalvo, K. Nash, M. Osherson, H. Saka, S. Salur, S. Schnetzer, D.
Sheffield, S. Somalwar, R. Stone, S. Thomas, P. Thomassen, M. Walker
University of Tennessee, Knoxville, USA
A.G. Delannoy, M. Foerster, J. Heideman, G. Riley, K. Rose, S. Spanier, K.
Thapa Texas A&M University, College Station, USA
O. Bouhali69, A. Castaneda Hernandez69, A. Celik, M. Dalchenko, M. De Mattia,
A. Delgado, S. Dildick, R. Eusebi, J. Gilmore, T. Huang, T. Kamon70, R.
Mueller, Y. Pakhotin, R. Patel, A. Perloff, L. Perniè, D. Rathjens, A.
Safonov, A. Tatarinov, K.A. Ulmer Texas Tech University, Lubbock, USA
N. Akchurin, J. Damgov, F. De Guio, P.R. Dudero, J. Faulkner, E. Gurpinar, S.
Kunori, K. Lamichhane, S.W. Lee, T. Libeiro, T. Mengke, S. Muthumuni, T.
Peltola, S. Undleeb, I. Volobouev, Z. Wang Vanderbilt University, Nashville,
USA
S. Greene, A. Gurrola, R. Janjam, W. Johns, C. Maguire, A. Melo, H. Ni, K.
Padeken, P. Sheldon, S. Tuo, J. Velkovska, Q. Xu University of Virginia,
Charlottesville, USA
M.W. Arenton, P. Barria, B. Cox, R. Hirosky, M. Joyce, A. Ledovskoy, H. Li, C.
Neu, T. Sinthuprasith, Y. Wang, E. Wolfe, F. Xia Wayne State University,
Detroit, USA
R. Harr, P.E. Karchin, N. Poudyal, J. Sturdy, P. Thapa, S. Zaleski University
of Wisconsin - Madison, Madison, WI, USA
M. Brodski, J. Buchanan, C. Caillol, S. Dasu, L. Dodd, S. Duric, B. Gomber, M.
Grothe, M. Herndon, A. Hervé, U. Hussain, P. Klabbers, A. Lanaro, A. Levine,
K. Long, R. Loveless, T. Ruggles, A. Savin, N. Smith, W.H. Smith, D. Taylor,
N. Woods †: Deceased
1: Also at Vienna University of Technology, Vienna, Austria
2: Also at State Key Laboratory of Nuclear Physics and Technology, Peking
University, Beijing, China
3: Also at IRFU, CEA, Université Paris-Saclay, Gif-sur-Yvette, France
4: Also at Universidade Estadual de Campinas, Campinas, Brazil
5: Also at Universidade Federal de Pelotas, Pelotas, Brazil
6: Also at Université Libre de Bruxelles, Bruxelles, Belgium
7: Also at Institute for Theoretical and Experimental Physics, Moscow, Russia
8: Also at Joint Institute for Nuclear Research, Dubna, Russia
9: Now at Ain Shams University, Cairo, Egypt
10: Now at British University in Egypt, Cairo, Egypt
11: Now at Cairo University, Cairo, Egypt
12: Also at Université de Haute Alsace, Mulhouse, France
13: Also at Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State
University, Moscow, Russia
14: Also at Tbilisi State University, Tbilisi, Georgia
15: Also at CERN, European Organization for Nuclear Research, Geneva,
Switzerland
16: Also at RWTH Aachen University, III. Physikalisches Institut A, Aachen,
Germany
17: Also at University of Hamburg, Hamburg, Germany
18: Also at Brandenburg University of Technology, Cottbus, Germany
19: Also at MTA-ELTE Lendület CMS Particle and Nuclear Physics Group, Eötvös
Loránd University, Budapest, Hungary
20: Also at Institute of Nuclear Research ATOMKI, Debrecen, Hungary
21: Also at Institute of Physics, University of Debrecen, Debrecen, Hungary
22: Also at Indian Institute of Technology Bhubaneswar, Bhubaneswar, India
23: Also at Institute of Physics, Bhubaneswar, India
24: Also at University of Visva-Bharati, Santiniketan, India
25: Also at University of Ruhuna, Matara, Sri Lanka
26: Also at Isfahan University of Technology, Isfahan, Iran
27: Also at Yazd University, Yazd, Iran
28: Also at Plasma Physics Research Center, Science and Research Branch,
Islamic Azad University, Tehran, Iran
29: Also at Università degli Studi di Siena, Siena, Italy
30: Also at INFN Sezione di Milano-Bicocca; Università di Milano-Bicocca,
Milano, Italy
31: Also at Purdue University, West Lafayette, USA
32: Also at International Islamic University of Malaysia, Kuala Lumpur,
Malaysia
33: Also at Malaysian Nuclear Agency, MOSTI, Kajang, Malaysia
34: Also at Consejo Nacional de Ciencia y Tecnología, Mexico city, Mexico
35: Also at Warsaw University of Technology, Institute of Electronic Systems,
Warsaw, Poland
36: Also at Institute for Nuclear Research, Moscow, Russia
37: Now at National Research Nuclear University ’Moscow Engineering Physics
Institute’ (MEPhI), Moscow, Russia
38: Also at St. Petersburg State Polytechnical University, St. Petersburg,
Russia
39: Also at University of Florida, Gainesville, USA
40: Also at P.N. Lebedev Physical Institute, Moscow, Russia
41: Also at California Institute of Technology, Pasadena, USA
42: Also at Budker Institute of Nuclear Physics, Novosibirsk, Russia
43: Also at Faculty of Physics, University of Belgrade, Belgrade, Serbia
44: Also at University of Belgrade, Faculty of Physics and Vinca Institute of
Nuclear Sciences, Belgrade, Serbia
45: Also at Scuola Normale e Sezione dell’INFN, Pisa, Italy
46: Also at National and Kapodistrian University of Athens, Athens, Greece
47: Also at Riga Technical University, Riga, Latvia
48: Also at Universität Zürich, Zurich, Switzerland
49: Also at Stefan Meyer Institute for Subatomic Physics (SMI), Vienna,
Austria
50: Also at Gaziosmanpasa University, Tokat, Turkey
51: Also at Istanbul Aydin University, Istanbul, Turkey
52: Also at Mersin University, Mersin, Turkey
53: Also at Cag University, Mersin, Turkey
54: Also at Piri Reis University, Istanbul, Turkey
55: Also at Izmir Institute of Technology, Izmir, Turkey
56: Also at Necmettin Erbakan University, Konya, Turkey
57: Also at Marmara University, Istanbul, Turkey
58: Also at Kafkas University, Kars, Turkey
59: Also at Istanbul Bilgi University, Istanbul, Turkey
60: Also at Rutherford Appleton Laboratory, Didcot, United Kingdom
61: Also at School of Physics and Astronomy, University of Southampton,
Southampton, United Kingdom
62: Also at Instituto de Astrofísica de Canarias, La Laguna, Spain
63: Also at Utah Valley University, Orem, USA
64: Also at Beykent University, Istanbul, Turkey
65: Also at Bingol University, Bingol, Turkey
66: Also at Erzincan University, Erzincan, Turkey
67: Also at Sinop University, Sinop, Turkey
68: Also at Mimar Sinan University, Istanbul, Istanbul, Turkey
69: Also at Texas A&M University at Qatar, Doha, Qatar
70: Also at Kyungpook National University, Daegu, Korea