2017 019 30 Jan Neutral meson production up to high $p_{\mathrm{T}}$ at 2.76
TeV ALICE Collaboration††thanks: See Appendix A for the list of collaboration
members ALICE Collaboration

The invariant differential cross sections for inclusive $\pi^{0}$ and $\eta$
mesons at midrapidity were measured in pp collisions at $\sqrt{s}=2.76$ TeV
for transverse momenta $0.4<p_{\mathrm{T}}<40$ GeV/$c$ and
$0.6<p_{\mathrm{T}}<20$ GeV/$c$, respectively, using the ALICE detector. This
large range in $p_{\mathrm{T}}$ was achieved by combining various analysis
techniques and different triggers involving the electromagnetic calorimeter
(EMCal). In particular, a new single-cluster, shower-shape based method was
developed for the identification of high-$p_{\mathrm{T}}$ neutral pions, which
exploits that the showers originating from their decay photons overlap in the
EMCal. Above $4$ GeV/$c$, the measured cross sections are found to exhibit a
similar power-law behavior with an exponent of about $6.3$. Next-to-leading-
order perturbative QCD calculations differ from the measured cross sections by
about $30$% for the $\pi^{0}$, and between $30$–$50$% for the $\eta$ meson,
while generator-level simulations with PYTHIA 8.2 describe the data to better
than $10$–$30$%, except at $p_{\mathrm{T}}<1$ GeV/$c$. The new data can
therefore be used to further improve the theoretical description of $\pi^{0}$
and $\eta$ meson production.

##  1 Introduction

Measurements of identified hadron spectra in proton-proton (pp) collisions are
well suited to constrain predictions from Quantum Chromodynamics (QCD) [1].
Such predictions are typically calculated in the pertubative approximation of
QCD (pQCD) based on the factorization of the elementary short-range scattering
processes (such as quark–quark, quark–gluon and gluon–gluon scatterings)
involving large momentum transfer ($Q^{2}$) and long-range universal
properties of QCD that need to be experimentally constrained. The universal
properties are typically modeled by parton distribution functions (PDFs),
which describe the kinematic distributions of quarks and gluons within the
proton in the collinear approximation, and fragmentation functions (FFs),
which describe the probability for a quark or gluon to fragment into hadrons
of a certain type. The cross section for the production of a given hadron of
type H can be written as a sum over parton types

$E\frac{d^{3}\sigma^{\rm H}}{d\vec{p}}=\sum_{a,b,c}f_{a}(x_{1},Q^{2})\otimes
f_{b}(x_{2},Q^{2})\otimes D_{c}^{H}(z_{c},Q^{2})\otimes
d\hat{\sigma}_{ab\rightarrow cX}(Q^{2},x_{1},x_{2})\,,$ (1)

where $f_{i}(x)$ denotes the proton PDF of parton $i$ carrying a fraction $x$
of the proton’s longitudinal momentum, $D^{H}_{i}(z_{i})$ the FF of parton $i$
into hadron H carrying a fraction $z_{i}$ of the parton’s momentum, and
$d\hat{\sigma}_{ij\rightarrow kX}$ the inclusive short-distance scattering
cross section of partons $i$ and $j$ into $k$ (see e.g. [2]).

Measurements of hadron production provide constraints on the PDFs and FFs,
which are crucial for pQCD predictions, and at LHC energies probe rather low
values of $x\sim 0.001$ and $z\sim 0.1$. The neutral pion ($\pi^{0})$ is of
special interest because as the lightest hadron it is abundantly produced, and
at LHC collision energies below a transverse momentum ($p_{\mathrm{T}}$) of
$20$ GeV/$c$ dominantly originates from gluon fragmentation. While the
collision energy ($\sqrt{s}$) dependence of $\pi^{0}$ cross sections has been
useful for guiding the parametrization of the FFs [3], experimental data for
neutral pions [4, 5] at the LHC are not available above $20$ GeV/$c$, where
quark fragmentation starts to play a role. The new $\pi^{0}$ data presented in
this paper extend our previous measurement [5] in pp collisions at
$\sqrt{s}=2.76$ TeV to $p_{\mathrm{T}}$ values of $40$ GeV/$c$ allowing one to
investigate the $p_{\mathrm{T}}$ dependence of the $\pi^{0}$ cross section at
high transverse momentum. In addition, we present the cross section of the
$\eta$ meson, which due to its strange quark content provides access to the
study of possible differences of fragmentation functions with and without
strange quarks [6]. Furthermore, the $\eta$ meson constitutes the second most
important source of decay photons and electrons after the $\pi^{0}$. Hence,
$\pi^{0}$ and $\eta$ meson spectra over a large $p_{\mathrm{T}}$ range are
needed for a precise characterization of the decay photon (electron)
background for direct photon (semileptonic open charm and beauty)
measurements.

The new measurement of the $\pi^{0}$ cross section is a result of five
analyses using data from various ALICE detector systems and different
identification techniques. The decay photons are either measured directly in
the Electromagnetic Calorimeter (EMCal), the Photon Spectrometer (PHOS) or via
the photon conversion method (PCM). In the PCM measurement, the photons are
reconstructed via their conversions into $e^{+}e^{-}$ pairs within the
detector material, where the $e^{+}e^{-}$ pairs are reconstructed with the
charged-particle tracking systems. The $\pi^{0}$ is reconstructed
statistically using the invariant mass technique. At high $p_{\mathrm{T}}$,
where the decay photons are too close together to be resolved individually,
the $\pi^{0}$ can still be measured via the characteristic shape of their
energy deposition in the EMCal. We combine statistically independent analyses
where (i) both photons are individually resolved in the EMCal (EMC), (ii) one
photon is identified in the EMCal and one is reconstructed via its conversion
to $e^{+}e^{-}$ (PCM-EMC), and (iii) the photon pair’s energy is merged in the
EMCal (mEMC). Finally, the previously published measurements based on methods
where both photons are reconstructed with (iv) PHOS or (v) PCM are included as
well [5]. The addition of the EMCal based measurements extends the
$p_{\mathrm{T}}$ reach from $12$ GeV/$c$ to $40$ GeV/$c$, the highest
$p_{\mathrm{T}}$ for identified hadrons achieved so far. The $\eta$ meson
cross section that was previously not available at $\sqrt{s}=2.76$ TeV is
measured in the range from $0.6$ to $20$ GeV/$c$ using the PCM, PCM-EMC and
EMC methods. Consequently, the $\eta/\pi^{0}$ ratio is measured in the same
$p_{\mathrm{T}}$ range.

The article is organized as follows:

##  2 sec:aliceDet

briefly describes the experimental setup.

##  3 sec:datasamples

describes the data samples and event selection.

##  4 sec:reco

describes the neutral meson reconstruction techniques and corresponding
corrections for the cross section measurements.

##  5 sec:corrsys

discusses the systematic uncertainties of the various measurements.

##  6 sec:results

presents the data and comparison with calculations and

##  7 sec:summary

provides a summary.

##  8 ALICE detector

A detailed description of the ALICE detector systems and their performance can
be found in Refs. [7, 8]. The new measurements primarily use the
Electromagnetic Calorimeter (EMCal), the Inner Tracking System (ITS), and the
Time Projection Chamber (TPC) at mid-rapidity, which are positioned within a
$0.5$ T solenoidal magnetic field. Two forward scintillator arrays (V0A and
V0C) subtending a pseudorapidity ($\eta$) range of $2.8<\eta<5.1$ and
$-3.7<\eta<-1.7$, respectively, provided the minimum bias trigger, which will
be further discussed in the next section.

The ITS [7] consists of two layers of Silicon Pixel Detectors (SPD) positioned
at a radial distance of 3.9 cm and 7.6 cm, two layers of Silicon Drift
Detectors (SDD) at 15.0 cm and 23.9 cm, and two layers of Silicon Strip
Detectors (SSD) at 38.0 cm and 43.0 cm from the beamline. The two SPD layers
cover a pseudorapidity range of $|\eta|<2$ and $|\eta|<1.4$, respectively. The
SDD and the SSD subtend $|\eta|<0.9$ and $|\eta|<1.0$, respectively. The
primary vertex can be reconstructed with a precision of
$\sigma_{z(xy)}=A/\sqrt{(\mathrm{d}N_{\mathrm{ch}}/\mathrm{d}\eta)^{\beta}}\oplus
B$, where $A\approx 600$ ($300$) $\mu$m, for the longitudinal ($z$) and
transverse ($xy$) directions, respectively, $B\approx 40$ $\mu$m and
$\beta\approx 1.4$.

The TPC [9] is a large (90 m3) cylindrical drift detector filled with a Ne/CO2
gas mixture. It covers a pseudorapidity range of $|\eta|<0.9$ over the full
azimuthal angle for the maximum track length of 159 reconstructed space
points. The ITS and the TPC were aligned with respect to each other to a
precision better than $100~{}\mathrm{\mu m}$ using tracks from cosmic rays and
proton-proton collisions [10]. The combined information of the ITS and TPC
allows one to determine the momenta of charged particles in the range of
$0.05$ to $100$ GeV/$c$ with a resolution between $1$% at low $p_{\mathrm{T}}$
and $10$% at high $p_{\mathrm{T}}$. In addition, the TPC provides particle
identification via the measurement of the specific energy loss (d$E$/d$x$)
with a resolution of $\approx$5%. The tracking detectors are complemented by
the Transition Radiation Detector (TRD) and a large time-of-flight (TOF)
detector. These detectors were used to estimate the systematic uncertainty
resulting from the non-perfect knowledge of the material in front of the
EMCal.

The EMCal [11] is a layered lead-scintillator sampling calorimeter with
wavelength shifting fibers for light collection. The overall EMCal covers
$107^{\rm o}$ in azimuth and $-0.7\leq\eta\leq 0.7$ in pseudorapidity. The
detector consists of $12288$ cells (also called towers) with a size of
$\Delta\eta\times\Delta\varphi=0.0143\times 0.0143$ corresponding to about
twice the effective Molière radius; the cells are read out individually. With
a depth of $24.6$ cm, or $\approx 20$ radiation lengths, $2\times 2$ cells
comprise a physical module. The $3072$ modules are arranged in $10$ full-sized
and $2$ one-third-sized supermodules, consisting of $12\times 24$ and $4\times
24$ modules, respectively, of which only the full-sized modules, corresponding
to an azimuthal coverage of $100^{\rm o}$, were readout for the data recorded
in $2011$–$2013$. 111The detector was installed in its complete configuration
by early 2012, while $4$ and $10$ full-sized supermodules were present in 2010
and 2011, respectively. The modules are installed with a radial distance to
the nominal collision vertex of $4.28$ m at the closest point, and assembled
to be approximately projective in $\eta$. The scintillation light from each
cell is collected with wavelength shifting fibers that are connected to a
$5\times 5$ mm2 active-area avalanche photodiode. The relative energy and
position resolutions improve with rising incident energy of the particle [12].
The energy resolution can be described by a constant and two energy dependent
terms parametrized as
$\frac{\sigma_{E}}{E}=A^{2}\oplus\frac{B^{2}}{E}\oplus\frac{C^{2}}{E^{2}}$%
with $A=1.7\pm 0.3$, $B=11.3\pm 0.5$, $C=4.8\pm 0.8$ and $E$ in GeV. The
position resolution is linear as a function of $1/\sqrt{E}$ and parametrized
as $1.5{\rm mm}+\frac{5.3{\rm mm}}{\sqrt{E}}$ with $E$ in GeV. Starting with
the highest cell $E_{\rm seed}>0.5$ GeV, the energy depositions from directly
adjacent EMCal cells with $E_{\rm cell}>0.1$ GeV are combined to form clusters
representing the total energy and physical position of incident particles [8].
The clustering algorithm allows only one local energy maximum in a cluster; if
a second is found a new cluster is initiated. Each cell is restricted to only
be part of one cluster. Individual cells were calibrated using the $\pi^{0}$
mass peak position evaluated cell-by-cell, achieving a relative variation of
below $1$%.

##  9 Data samples and event selection

The data presented in this paper were recorded during the 2011 and 2013
periods with pp collisions at $\sqrt{s}=2.76~{}\mathrm{TeV}$. Various EMCal
triggers were employed and, while the majority of the minimum bias data were
recorded in 2011, the 2013 running period took advantage of higher threshold
EMCal triggers to collect a notable high-$p_{\mathrm{T}}$ data sample. For the
pp data collected in 2011, the minimum bias trigger (MBOR) required a hit in
either V0 detector or a hit in the SPD, while it required hits in both V0
detectors for the data collected in 2013 (MBAND). The respective cross
sections were determined based on van-der-Meer scans, and found to be
$\sigma_{\rm MB_{AND}}=47.7\pm 0.9$ mb with $\sigma_{\rm MB_{AND}}/\sigma_{\rm
MB_{OR}}=0.8613\pm 0.0006$ and $\sigma_{\rm MB_{AND}}/\sigma_{\rm
inel}=0.760^{+0.052}_{-0.028}$ [13]. For the normalisation of the 2013 data,
for which there was no vdM scan, the uncertainty $\sigma_{\rm MB_{AND}}$ was
conservatively increased to $4$%, to account for possible variations of the
MBAND trigger efficiency between 2011 and 2013. The resulting uncertainty due
to the luminosity determination is $2.5$% for both datasets together.

The EMCal issues triggers at two different levels, Level 0 (L0) and Level 1
(L1). The events accepted at L0 are further processed at L1. The L0 decision,
issued latest $1.2$ $\mu$s after the collision, is based on the analog charge
sum of $2\times 2$ adjacent cells evaluated with a sliding window algorithm
within each physical Trigger Region Unit (TRU) spanning $4\times 24$ cells in
coincidence with a minimum bias trigger. The L1 trigger decision, which must
be taken within $6.2$ $\mu$s after the collision, can incorporate additional
information from different TRUs, as well as other triggers or detectors. The
data presented in this paper used the photon (EG) trigger at L1, which extends
the $2\times 2$ sliding window search across neighboring TRUs, resulting in a
$\approx 30$% larger trigger area than the L0 trigger.

Figure 1: Energy dependence of ratios between cluster spectra for EMC1/INT1,
EMC7/INT7, EG2/EMC7 and EG1/EG2. The trigger names INT1 and INT7 denote the
minimum bias triggers MBOR and MBAND respectively. The trigger names EMC1,
EMC7, EG2 and EG1 denote the EMCal triggers at L0 in 2011 and 2013, and the
EMCal triggers at L1 in 2013 with increasing threshold respectively. The
individual trigger rejection factors and their respective fit ranges in the
plateau region are indicated as well. The final rejection factors with respect
to the minimum bias trigger are given in Tab. 1.

In 2011, only the L0 trigger was used with one threshold (EMC1), while in
2013, one L0 (EMC7) and two L1 triggers (EG1, EG2) with different thresholds
were used, as summarized in Tab. 1. The lower L1 trigger threshold in 2013 was
set to approximately match the L0 threshold in 2011 for consistency. In case
an event was associated with several triggers, the trigger with the lowest
threshold was retained.

However, the thresholds are configured in the hardware via analog values, not
actual units of energy. Their transformation into energy values directly
depends on the energy calibration of the detector. For a reliable
normalization of each trigger, the Trigger Rejection Factor ($R_{\rm Trig}$)
is used. The $R_{\rm Trig}$ takes into account a combination of the
efficiency, acceptance and the downscaling of the respective triggers. It can
be obtained from the ratio $R$ of the number of clusters reconstructed in
EMCal triggered events to those in minimum bias events at high cluster energy
$E$ where $R$ should be approximately constant (plateau region), assuming the
trigger does not affect the cluster reconstruction efficiency, but only the
overall rate of clusters. To reduce the statistical uncertainties on the
normalization for the higher threshold triggers, $R_{\rm Trig}$ was always
estimated with respect to the trigger with the next lower threshold in the
EMCal or the respective minimum bias trigger if no lower EMCal trigger was
available. By consecutively multiplying the individual rejection factors up to
the minimum bias trigger, the final $R_{\rm Trig}$ was obtained with respect
to the minimum bias trigger. The energy dependence of the ratios between
cluster spectra of the relevant trigger combinations (EMC1/INT1, EMC7/INT7,
EG2/EMC7 and EG1/EG2) are shown in Fig. 1. At low $E$, there is a minimum at
roughly the threshold of the lower-level trigger for EG2/EMC7 and EG1/EG2,
while at high $E$ there is a pronounced plateau for every trigger combination.
The averages above the threshold in the plateau region, which represent
$R_{\rm Trig}$ for the respective trigger combinations, are indicated by a
line whose width represents the respective statistical uncertainty. The
corresponding systematic uncertainties were obtained by varying the range for
the fit of the plateau region. Finally, the values for the average trigger
rejection factors above the threshold with respect to the corresponding
minimum bias triggers are given in Tab. 1. For the PCM-EMC and EMC analyses,
all available triggers were used, while for mEMC only the EMC1, EG2 and EG1
triggers were included. The collected integrated luminosities for minimum bias
and EMCal triggers

$L_{\rm int}=\frac{N_{\rm trig}}{\sigma_{\rm MB}}\,R_{\rm trig}\,,$ (2)

where $\sigma_{\rm MB}$ refers to $\sigma_{\rm MB_{OR}}$ for 2011 and
$\sigma_{\rm MB_{AND}}$ for 2013, are summarized in Tab. 1. The statistical
uncertainties on $R_{\rm Trig}$ are treated as systematic uncertainties on the
integrated luminosity.

Year | Trigger | Trigger | Approx. | Trigger rejection | $L_{\text{int}}$
---|---|---|---|---|---
|  | name | threshold | factor ($R_{\rm Trig}$) | $(\text{nb}^{-1})$
2011 | MBOR | INT1 | $0$ | $1$ | $0.524\pm 0.010$
| EMCal L0 | EMC1 |  $3.4$ GeV | $1217\pm 67$ | $13.8\pm 0.806$
2013 | MBAND | INT7 | $0$ | $1$ | $0.335\pm 0.013$
| EMCal L0 | EMC7 |  $2.0$ GeV | $126.0\pm 4.3$ | $1.19\pm 0.062$
| EMCal L1 (G2) | EG2 |  $3.5$ GeV | $1959\pm 131$ | $6.98\pm 0.542$
| EMCal L1 (G1) | EG1 |  $5.5$ GeV | $7743\pm 685$ | $47.1\pm 4.57$
Table 1: Approximate trigger threshold and corresponding trigger rejection
factor for EMCal triggers, as well as integrated luminosity for minimum bias
and various EMCal triggers.

Monte Carlo (MC) samples were generated using PYTHIA8 [14] and PHOJET [15].
The correction factors obtained independently from the two MC samples were
found to be consistent, and hence combined. For mesons with $p_{\mathrm{T}}>5$
GeV/$c$, as in the triggered or merged cluster analyses, PYTHIA6 [16]
simulations enriched with jets generated in bins of the hard scattering
($p_{\mathrm{T,hard}}$) were used. All MC simulations were obtained for a full
ALICE detector description using the GEANT3 [17] framework and reconstructed
with the same algorithms as for the data processing.

The different triggers of the EMCal affect the properties of the
reconstructible mesons, like the energy asymmetry
($\alpha=\frac{E_{1}-E_{2}}{E_{1}+E_{2}}$) of the decay photons, and hence
significantly alter the reconstruction efficiency above the trigger threshold
in the trigger turn-on region. The efficiency biases $\kappa_{\rm Trig}$
induced by the triggers were simulated using the approximate thresholds and
their spread for different TRUs. The bias was defined as the ratio of the
$\pi^{0}$ or $\eta$ reconstruction efficiency in triggered events over that in
minimum bias events. Figure 2 shows the $p_{\mathrm{T}}$ dependence of
$\kappa_{\rm Trig}$ for different triggers and reconstruction methods for the
$\pi^{0}$ and $\eta$ meson. While $\kappa_{\rm Trig}$ is unity for the mEMC
analysis in the considered kinematic range, it is significantly below one for
the PCM-EMC and EMC neutral meson reconstruction, and reaches $\approx 1$ only
at about twice the trigger threshold. The corresponding correction factors are
found to be larger for the PCM-EMC compared to the EMC method, and larger for
the $\eta$ than the $\pi^{0}$ meson. This is a consequence of the much lower
energy threshold imposed on the photons reconstructed with PCM, which leads to
wider opening angle and asymmetry distributions of the reconstructible mesons.
At low $p_{\mathrm{T}}$, $\kappa_{\rm Trig}$ also exhibits the effect of the
trigger on subleading particles, for which the efficiency in triggered events
is strongly reduced. However, the various triggers are only used if the meson
momentum is at least 1.5 times the trigger threshold, thus the effect on the
subleading particles is neglible.

In the offline analysis, only events with a reconstructed vertex with
$|z_{\mathrm{vtx}}|<10~{}\mathrm{cm}$ with respect to the nominal interaction
vertex position along the beam direction were used. The finite primary vertex
reconstruction efficiency for the MBOR(MBAND) trigger of about $0.92$ ($0.98$)
is taken into account in the normalization of the respective minimum bias
triggers. Furthermore, only events with exactly one reconstructed vertex were
accepted to remove pileup from in- and out-of-bunch collisions. While the in-
bunch pileup is negligible after the vertex selection, the out-of-bunch pileup
accumulating in the TPC due to its readout time of $90~{}\mathrm{ms}$, needs
to be subtracted statistically for the mesons measured with PCM, as described
in LABEL:Abelev:2014ypa. For the $\pi^{0}$ ($\eta$) mesons reconstructed with
PCM the out-of-bunch pileup correction ranges from $20\%$ ($9\%$) at low
$p_{\mathrm{T}}$ to about $3\%$ above $4$ GeV/$c$. Analyses involving the
EMCal are not affected because contributions of clusters from different bunch
crossings are suppressed by a suitable selection of clusters within a certain
time window around the main bunch crossing.

Figure 2: Efficiency bias $\kappa_{\rm Trig}$ induced by different triggers
(EMC1, EMC7 and EG1) for neutral pions (left panel) and $\eta$ mesons (right
panel) for PCM-EMC (open symbols) and EMC (closed symbols).

##  10 Neutral meson reconstruction

Neutral mesons decaying into two photons fulfill

$M=\sqrt{2E_{1}E_{2}(1-\cos\theta_{12})}$ (3)

where $M$ is the reconstructed mass of the meson, $E_{1}$ and $E_{2}$ are the
measured energies of two photons, and $\theta_{12}$ is the opening angle
between the photons measured in the laboratory frame. Photon candidates are
measured either by a calorimeter or by PCM. Neutral meson candidates are then
obtained by correlating photon candidates measured either by EMC, PHOS or PCM
exclusively, or by a combination of them (PCM-EMC). The corresponding
$\pi^{0}$ and $\eta$ meson measurements are described in Sect. 10.1. The
typical opening angle $\theta_{12}$ decreases with increasing $p_{\mathrm{T}}$
of the meson due to the larger Lorentz boost. For $\pi^{0}$ mesons with
$p_{\mathrm{T}}$ above $5$–$6$ GeV/$c$, the decay photons become close enough
so that their electromagnetic showers overlap in neighboring calorimeter cells
of the EMCal. At $p_{\mathrm{T}}$ above $15$ GeV/$c$, the clustering algorithm
can no longer efficiently distinguish the individual showers in the EMCal, and
$\pi^{0}$ mesons can be measured by inspecting the shower shape of single
clusters, referred to as “merged” clusters and explained in Sect. 10.2.

To be able to directly compare the reconstruction performances of the various
measurement techniques and triggers, the invariant differential neutral meson
cross sections were expressed as

$E\frac{\mathrm{d}^{3}\sigma}{\mathrm{d}p^{3}}=\frac{N_{\rm
rec}}{p_{\mathrm{T}}\,\Delta p_{\mathrm{T}}\,\kappa_{\rm
Trig}\,\varepsilon}\,\frac{1}{L_{\rm int}}\,\frac{1}{\rm BR}$ (4)

with the inverse of the normalized efficiency

$\frac{1}{\varepsilon}=\frac{1}{2\pi\,A\,\Delta y\,}\frac{P}{\varepsilon_{\rm
rec}}$ (5)

and integrated luminosity (see Eq. 2). The measured cross sections were
obtaind by correcting the reconstructed meson yield $N_{\rm rec}$ for
reconstruction efficiency $\varepsilon_{\rm rec}$, purity $P$ and acceptance
$A$, efficiency bias $\kappa_{\rm Trig}$, integrated luminosity $L_{\rm int}$,
as well as for the $p_{\mathrm{T}}$ and $y$ interval ranges, $\Delta
p_{\mathrm{T}}$ and $\Delta y$, respectively, and the $\gamma\gamma$ decay
branching ratio $BR$. For invariant mass methods, the effect of reconstructed
photon impurities on the meson purity are significantly reduced due to the
subtraction of the combinatorial background, and hence the resulting meson
impurities were neglected. For the mEMC method, the $\pi^{0}$ purity
correction was obtained from MC simulations tuned to data. In the case of
neutral pions, the contribution from secondary $\pi^{0}s$ was subtracted from
$N_{\rm rec}$ before applying the corrections. The contribution from weak
decays was estimated for the different methods by simulating the decays of the
K${}^{0}_{\rm S}$ and $\Lambda$ using their measured spectra [18], taking into
account the reconstruction efficiencies, as well as resolution and acceptance
effects for the respective daughter particles The contribution from neutral
pions produced by hadronic interactions in the detector material was estimated
based on the full detector simulations using GEANT3. Finally, the results were
not reported at the center of the $p_{\mathrm{T}}$ intervals used for the
measurements, but following the prescription in LABEL:Lafferty:1994cj at
slightly lower $p_{\mathrm{T}}$ values, in order to take into account the
effect of the finite bin width $\Delta p_{\mathrm{T}}$. The correction was
found to be less than $1$% in every $p_{\mathrm{T}}$ interval for the
$\pi^{0}$, and between $1$–$4$% for the $\eta$ meson.

###  10.1 Invariant mass analyses

Applying Eq. 3, the invariant mass distribution is obtained by correlating all
pairs of photon candidates per event. The neutral meson yield is then
statistically extracted using the distinct mass line shape for identification
of the signal and a model of the background. In the following, only the new
measurements are described. Details of the PCM and PHOS $\pi^{0}$ measurements
can be found in Refs. [4, 5].

Track selection |
---|---
Track quality selection |  $p_{\mathrm{T}}>0.05$ GeV/$c$
| $N_{\rm TPC\ cluster}/N_{\rm reconstructible\ clusters}>0.6$
| $|\eta|<0.9$
Electron selection | $-4<n\sigma_{\rm e}<5$
Pion rejection |  $n\sigma_{\rm\pi}<1$ for $0.4<p<3.5$ GeV/$c$,
|  $n\sigma_{\rm\pi}<0.5$ for $p>3.5$ GeV/$c$ (PCM)
|  $n\sigma_{\rm\pi}<1$ for $p>0.4$ GeV/$c$ (PCM-EMC)
Photon criteria |
Conversion point | $|\eta_{\rm V^{0}}|<0.9$
|  $5$ cm $<R_{\rm conv}<180$ cm
|  $|Z_{\rm conv}|<240$ cm
| $0\leq|\varphi_{\rm conv}|\leq 2\pi$
| $\text{cos}(\theta_{\text{point}})>0.85$
Photon quality |  $|\psi_{\rm pair}|<\psi_{\rm pair,max}-\frac{\psi_{\rm pair,max}}{\chi^{2}_{\rm red,max}}\chi_{\rm red}^{2}$,
| with $\psi_{\rm pair,max}$$~{}=~{}0.1$ and $\chi^{2}_{\rm
red,max}$$~{}=~{}30$
Armenteros-Podolanski |  $q_{\mathrm{T}}<q_{\mathrm{T,max}}\sqrt{1-\frac{\alpha^{2}}{\alpha_{\mathrm{max}}^{2}}}$,
| with $q_{\mathrm{T,max}}=0.05$ GeV/$c$ and $\alpha_{\mathrm{max}}=0.95$
Table 2: Criteria for photon candidate selection for PCM.

For the reconstruction of photons with PCM, only tracks from secondary
vertices without kinks with a minimum momentum of $0.05$ GeV/$c$ were taken
into account. The tracks had to be reconstructed within the fiducial
acceptance of the TPC and ITS and with at least $60$% of the reconstructible
track points in the TPC. The photon momentum resolution is better than $1.5$%
at low $p_{\mathrm{T}}$, resulting from the precise determination of the track
momenta by the TPC. Furthermore, the associated energy loss measured in the
TPC was required to be within $-4<n\sigma_{e}<5$ of the electron expectation,
where $n\sigma_{X}=({\rm d}E/{\rm d}x-\left\langle{\rm d}E/{\rm
d}x_{X}\right\rangle)/\sigma_{X}$ with $\left\langle{\rm d}E/{\rm
d}x_{X}\right\rangle$ and $\sigma_{X}$ the average energy loss and resolution
for particle $X$, respectively. The contamination from charged pions was
suppressed by excluding all track candidates within $n\sigma_{\pi}<1$ of the
pion expectation. The charged pion rejection was applied for track momenta
between $0.4<p<3.5$ GeV/$c$ for PCM and $p>0.4$ GeV/$c$ for PCM-EMC, while for
PCM it was released to $n\sigma_{\pi}<0.5$ above $p=3.5$ GeV/$c$. Only
conversions which were pointing to the primary vertex and could be
reconstructed with a conversion point with $5<R_{\rm conv}<180$ cm within the
acceptance of the ITS and TPC were considered. Compared to previous PCM
standalone measurements [5], the photon candidate selection criteria were
optimized in order to reduce the combinatorial background. In particular, a
two dimensional selection on the reduced $\chi^{2}$ of the photon conversion
fit and the angle between the plane defined by the conversion pair and the
magnetic field $|\psi_{\rm pair}|$ was introduced to suppress random
$e^{+}e^{-}$ pairs. Furthermore, the selection in the Armenteros-Podolanski
variables [20] was tightened to reduce the contamination from K${}^{0}_{\rm
S}$ and $\Lambda$ decays. A summary of the conversion photon selection
criteria is given in Tab. 2.

Clusters in the EMCal were reconstructed by aggregating cells with $E_{\rm
cell}>0.1$ GeV to a leading cell energy with at least $E_{\rm seed}>0.5$ GeV,
and were required to have only one local maximum. Photon candidates were
obtained from reconstructed clusters by requiring a cluster energy of $0.7$
GeV to ensure acceptable timing and energy resolution and to remove
contamination from minimum-ionizing ($\stackrel{{\scriptstyle<}}{{\sim}}300$
MeV) and low-energy hadrons. Furthermore, a cluster had to contain at least
two cells to ensure a minimum cluster size and to remove single cell
electronic noise fluctuations. Clusters which could be matched to a track
propagated to the average shower depth in the EMCal (at $440$ cm) within
$|\Delta\eta|$ and $|\Delta\varphi|$ criteria that depend on track
$p_{\mathrm{T}}$ as given in Tab. 3, were rejected to further reduce
contamination by charged particles. The track-to-cluster matching efficiency
amounts to about $97$% for primary charged hadrons at cluster energies of
$E_{\rm clus}>0.7$ GeV, decreasing slowly to $92$% for clusters of $50$ GeV.
The removal of matched tracks is particularly important for the PCM-EMC method
as otherwise a severe auto-correlation between the clusters originating from
one of the conversion electrons and the conversion photon would be introduced.
Such auto-correlated pairs strongly distort the shape of the invariant mass
distribution between the $\pi^{0}$ and $\eta$ mass peak region. The standard
track matching applied to each conversion leg allowed for the removal of these
auto-correlation pairs with an efficiency of more than $99\%$ since the
corresponding track was already found. An additional distinction between
clusters from mainly photons, electrons and neutrons is based on their shower
shape. The shower shape can be characterized by the larger eigenvalue squared
of the cluster’s energy decomposition in the EMCal $\eta$–$\varphi$ plane. It
is expressed as

$\sigma^{2}_{\rm
long}=0.5\left(\sigma_{\varphi\varphi}^{2}+\sigma_{\eta\eta}^{2}+\sqrt{(\sigma_{\varphi\varphi}^{2}-\sigma_{\eta\eta}^{2})^{2}+4\sigma^{4}_{\varphi\eta}}\right)$
(6)

where $\sigma^{2}_{xz}=\left<x\,z\right>-\left<x\right>\left<z\right>$ and
$\left<x\right>=\frac{1}{w_{\rm tot}}\sum w_{i}x_{i}$ are weighted over all
cells associated with the cluster in the $\varphi$ or $\eta$ direction. The
weights $w_{i}$ logarithmically depend on the ratio of the energy of a given
cell to the cluster energy, as $w_{i}=\max\left(0,4.5+\log E_{i}/E\right)$,
and $w_{\rm tot}=\sum w_{i}$ [21]. Nuclear interactions, in particular for
neutrons, create an abnormal signal when hitting the corresponding avalanche
photodiodes for the readout of the scintillation light. Such a signal is
mainly localized in one high-energy cell with a few surrounding low-energy
cells, and can be removed by requiring $\sigma^{2}_{\rm long}>0.1$. While the
showers from electrons and photons tend to be similar, they can be
distinguished based on their elongation, as most of the low-$p_{\mathrm{T}}$
electrons will hit the EMCal surface at an angle due to the bending in the
magnetic field. Most of the pure photons are reconstructed with a
$\sigma^{2}_{\rm long}\approx 0.25$; only late conversions elongate the
showers beyond this. Thus, rejecting clusters with $\sigma^{2}_{\rm long}>0.7$
$(0.5)$ for EMC (PCM-EMC) rejects the contamination from late conversion
electrons significantly. At very high transverse momenta ($>10$ GeV/$c$), it
also rejects part of the contamination from neutral pions for which both
photons have been reconstructed in a single cluster. Contributions of clusters
from different bunch crossings were suppressed by a suitable selection of
clusters within a certain time window around the main bunch crossing. A
summary of the selection criteria for EMCal photon candidates is given in Tab.
3.

Cluster reconstruction |
---|---
Minimum cell energy |  $E_{\rm cell}>0.1$ GeV
Minimum leading cell energy |  $E_{\rm seed}>0.5$ GeV
Cluster selection |
Selection in $\eta$ |  $\left|\eta\right|<0.67$, $1.40~{}\mathrm{rad}<\varphi<3.15~{}\mathrm{rad}$
Minimum cluster energy |  $E_{\rm clus}>0.7$ GeV
Minimum number of cells | $N_{\rm cells}\geq 2$
Cluster-shape parameter |  $0.1<$ $\sigma^{2}_{\rm long}<0.5$ (PCM-EMC)
|  $0.1<$ $\sigma^{2}_{\rm long}<0.7$ (EMC)
|  $\sigma^{2}_{\rm long}>0.27$ (mEMC)
Cluster time |  $|t_{\rm clus}|\leq 50$ ns (2011)
|  $-35$ ns $<t_{\rm clus}<30$ ns (2013)
Cluster–track matching | $|\Delta\eta|\leq 0.010+\left({p_{\mathrm{T}}+4.07}\right)^{-2.5}$
| $|\Delta\varphi|\leq 0.015+\left({p_{\mathrm{T}}+3.65}\right)^{-2}$
Table 3: Criteria for photon candidate selection for EMCal-based methods.

The good momentum resolution for the PCM photon was exploited to derive an
improved correction for the relative energy scale, as well as for the residual
misalignment of the EMCal between data and simulation. The neutral pion mass
was evaluated for the PCM-EMC method as a function of the EMCal photon energy
for data and simulation. A correction for the cluster energy was deduced which
for a given simulation adjusts the neutral pion mass peak position to the
measured position in the data as a function of the cluster energy. Above $1$
GeV, the corrections for the various MC datasets are typically about 3%.

Figure 3: Invariant mass distributions in the $\pi^{0}$ peak region for INT1
(left panels) and EG1 (right panels) triggers and EMC (top panels) and PCM-EMC
(bottom panels) methods.

Figure 4: Invariant mass distributions in the $\eta$ peak region for INT1
(left panels) and EG1 (right panels) triggers and EMC (top panels) and PCM-EMC
(bottom panels) methods.

Example invariant mass distributions obtained by correlating photons
reconstructed with EMCal or by one photon from PCM and one from EMCal are
shown in Fig. 3 for neutral pions and Fig. 4 for $\eta$ mesons. The
combinatorial background was calculated using the mixed event technique [22]
using event pools binned by primary vertex position, multiplicity and
transverse momentum. The mixed-event background has been normalized to the
right side of the $\pi^{0}(\eta)$ peak. Additionally, a residual correlated
background estimated using a linear fit was subtracted. Only pairs with a
minimum opening angle of $0.02$ ($0.005$) mrad for EMC (PCM and PCM-EMC)
methods were considered for signal and background construction. Finally, pairs
are restricted to rapidity of $|y|<0.8$.

Figure 5: Neutral pion (left panels) and $\eta$ meson (right panels) mass
position (bottom panels) and width (top panels) for the PCM, PCM-EMC and EMC
methods. The performance of PHOS for $\pi^{0}$ is taken from
LABEL:Abelev:2014ypa. Data are displayed as closed symbols, simulations as
open symbols.

A Gaussian with an exponential tail on the left side was fitted to the
subtracted invariant mass distributions, in order to determine the mass
position and width of the peak. The results of the fits for the mass position
and widths of neutral pions and $\eta$ mesons are shown in Fig. 5. The
performance of PHOS from LABEL:Abelev:2014ypa in the case of $\pi^{0}$ is
added for completeness. For all systems, the data for both $\pi^{0}$ and
$\eta$ are reproduced by the MC simulations to a precision on average better
than 0.3% for the mass position. For EMC, the $p_{\mathrm{T}}$-dependence of
the mass position is especially pronounced, due to non-linearity effects for
low $p_{\mathrm{T}}$ clusters, shower merging and shower overlaps, and decay
asymmetry enhanced by the employed triggers at high $p_{\mathrm{T}}$. The
widths of the meson peaks are similarly well described, with the expected
ordering for the various methods. In particular, the peak widths of the PCM-
EMC fits are between the standalone measurements of PCM and EMC and are
comparable to the PHOS measurement above 7 GeV/$c$. This illustrates that the
inclusion of one photon from PCM significantly improves the resolution of the
neutral meson measurements.

The neutral meson raw yield was extracted by integrating the background-
subtracted invariant mass distributions around the measured peak mass. The
integration windows for the different reconstruction techniques were adjusted
based on the average width of the meson peaks and their signal shape:
($M_{\pi^{0}}-0.035$, $M_{\pi^{0}}+0.010$), ($M_{\eta}-0.047$,
$M_{\eta}+0.023$) for PCM, ($M_{\pi^{0}}-0.032$, $M_{\pi}^{0}+0.022$),
($M_{\eta}-0.060$, $M_{\eta}+0.055$) for PCM-EMC, and ($M_{\pi^{0}}-0.05$,
$M_{\pi}^{0}+0.04$), ($M_{\eta}-0.080$, $M_{\eta}+0.08$) for EMC. For both
mesons, an asymmetric range around the measured mass position was used to
account for the low mass tail originating not only from the bremsstrahlung
energy loss of conversion electrons and positrons, but also from additional
missing energy in the EMCal due to the partial reconstruction of the photon.

Figure 6: Normalized efficiency for different methods of neutral pion (left
panel) and $\eta$ meson (right panel) reconstruction methods. The values for
PHOS are taken from [5].

The corrections for the geometric acceptance and reconstruction efficiency for
the different mesons were calculated using MC simulations as mentioned in
Sect. 9. The acceptance for the EMCal reconstruction techniques was calculated
as the fraction of $\pi^{0}$ ($\eta$), whose decay photons point to the EMCal
surface ($|\eta|<0.67,~{}1.40~{}\mathrm{rad}<\varphi<3.15~{}\mathrm{rad}$),
compared to the $\pi^{0}$ ($\eta$) generated with $|y|<0.8$. In the case of
PCM-EMC, only one photon was required to point to the EMCal surface, while the
other was required to be within the acceptance of the TPC
($|\eta|<0.9,~{}0~{}\mathrm{rad}<\varphi<2\pi~{}\mathrm{rad}$). The output
from the full event MC simulations was reconstructed and analyzed in the same
way as the data. The reconstruction efficiency was calculated as the fraction
of reconstructed mesons compared to the mesons whose decay photons passed the
acceptance criteria. The normalized efficiency $\varepsilon$ (see Eq. 5) as a
function of meson $p_{\mathrm{T}}$ is shown in Fig. 6 for the various methods.
For EMC, $\varepsilon$ rises at low $p_{\mathrm{T}}$ and reaches its maximum
at about $0.8$ at $10$ GeV/$c$. Subsequently, $\varepsilon$ drops due to the
merging of the two clusters, and is already a factor of $5$ smaller at about
$15$ GeV/$c$. In the case of the $\eta$, the efficiency at $15$ GeV/$c$ is not
yet affected by the cluster merging due to its higher mass. The efficiency for
PCM-EMC is approximately a factor $10$ smaller than for EMC for both mesons
due to the conversion probability of about $0.09$ in the respective
pseudorapidity window. For the $\pi^{0}$, it is similar to that of PHOS. The
small decrease at higher $p_{\mathrm{T}}$ for the PCM-EMC results from shower
overlaps of the EMC photon with one of the conversion legs, and thus a
stronger rejection of the EMCal photons due to track matching. Relative to
PCM-EMC, $\varepsilon$ for PCM is suppressed by the conversion probability
affecting both decay photons.

The correction for secondaries from hadronic interactions depends on
$p_{\mathrm{T}}$ for the EMC-related methods. It ranges from $1.2$% at the
lowest $p_{\mathrm{T}}$ to $0.1$% ($0.4$%) above $3$ GeV/$c$ for the PCM-EMC
(EMC) method. For PCM, the correction amounts to less than $0.2$% independent
of $p_{\mathrm{T}}$. However, the contribution of the neutral pions from
K${}^{0}_{\rm S}$ is strongly $p_{\mathrm{T}}$ dependent due to the tight
selection criteria forcing the photons to point to the primary vertex. The
correction drops quickly from about $8$% to less than $1$% at $4$ GeV/$c$. For
the PCM-EMC and EMC, the corresponding correction amounts to $0.9$% and
$1.6$%, respectively, independent of $p_{\mathrm{T}}$ in the measured
$p_{\mathrm{T}}$ range. Contributions from other weak decays are below 0.1%
and thus neglected for all reconstruction techniques.

###  10.2 Single cluster analysis

At high $p_{\mathrm{T}}$ the showers induced by the two decay photons from a
neutral pion merge into a single EMCal cluster, and therefore are
unidentifiable in an invariant mass analysis. Hence, for $\pi^{0}s$ above 15
GeV/$c$ we use a different approach, namely to reconstruct and identify
$\pi^{0}s$ based only on single clusters, exploiting that clusters at high
$p_{\mathrm{T}}$ mostly originate from merged $\pi^{0}$ decay photons.

Merged clusters from $\pi^{0}$ decays tend to be more elongated than clusters
from photons and electrons, and their deformation is reflected by the shower
shape $\sigma^{2}_{\rm long}$, defined in Eq. 6. The shower shape
distributions are shown for data and MC in Fig. 7 for $\pi^{0}$ candidates,
i.e. clusters fulfilling the selection criteria listed in Tab. 3 except
$\sigma^{2}_{\rm long}$. The $\sigma^{2}_{\rm long}$ distribution is found to
be fairly well described by the MC, in particular for $\sigma^{2}_{\rm
long}>0.3$. For $\sigma^{2}_{\rm long}>0.3$, the dominant contribution to
$\pi^{0}$ candidates is from merged $\pi^{0}$ showers, while for
$\sigma^{2}_{\rm long}<0.3$ clusters dominate where only the energy of one
decay photon contributed. The most significant background is from decay
photons of the $\eta$ meson and direct photons, located mainly at
$\sigma^{2}_{\rm long}<0.3$. Hence, for the mEMC measurement, $\pi^{0}$
candidates are simply required to have $\sigma^{2}_{\rm long}>0.27$ in order
to discriminate from $\eta$ decay and direct photons. Only candidates with a
rapidity of $|y|<0.6$ are considered.

The corrections for the geometric acceptance, reconstruction efficiency, and
purity were calculated using MC simulations as described in Sect. 9. The
resulting efficiency is shown in Fig. 6 compared to the other neutral pion
reconstruction techniques. At high $p_{\mathrm{T}}$, mEMC clearly has an
advantage due to its larger coverage compared to PHOS, and the exploitation of
merging of the $\pi^{0}$ decay photons in the EMCal.

Figure 7: Shower shape ($\sigma^{2}_{\rm long}$) distributions for $\pi^{0}$
candidates with $18<p_{\rm T}<22$ GeV/$c$ compared in data and MC (left
panel), and corresponding signal and background contributions in MC (right
panel).

The $\pi^{0}$ reconstruction efficiency was calculated by comparing the
reconstructed with generator-level $p_{\mathrm{T}}$ distributions within a
rapidity of $|y|<0.6$. By comparing measured and generated $p_{\mathrm{T}}$ of
the neutral pion, the $p_{\mathrm{T}}$ resolution correction is included in
the inefficiency correction. The resolution is significantly different for
candidate clusters containing all or only parts of the decay products, i.e.
single photons or conversions. If all $\pi^{0}$ decay products contribute to
the cluster, the mean momentum difference between reconstructed and generated
$p_{\mathrm{T}}$ is smaller than $2\%$ with an RMS of $16$–$25$% above $20$
GeV/$c$. Otherwise, the mean momentum difference can reach up to $30$%
depending on the fraction of decay particles which could be reconstructed and
whether they converted in the detector material.

The purity represents the fraction of reconstructed clusters that pass all the
selections and are from a $\pi^{0}$ decay. For $p_{\mathrm{T}}>16$ GeV/$c$, it
is almost constant at around $90$% with variations of $1$–$2$%. As can be seen
in Fig. 7, the largest contamination in the considered $\sigma^{2}_{\rm long}$
window originates from the $\eta$ meson decay ($\approx 5\%$ after fine-tuning
the $\eta/\pi^{0}$ ratio to the measured value), closely followed by the
hadronic background consisting mainly of charged pions ($\approx 2\%$) and
K${}^{0}_{\rm L}$ ($\approx 1.8\%$). The contamination from $\eta$ mesons
rises by about $2$% towards higher momenta, while the contamination from the
other two sources decrease by about $0.5$%. Fragmentation photons contribute
to the background about $1.2$%. Their contribution was additionally scaled up
by up to a factor $2$, given by the ratio of fragmentation photons to direct
photons according to NLO pQCD calculations [23, 24], to account for direct
photons which are not included in generator. Lastly, prompt electrons
contribute to the contamination about $0.7$%.

The correction for secondary pions from K${}^{0}_{\rm S}$ decays amounts to
approximately $5$%, as their reconstruction efficiency is very similar to that
of primary $\pi^{0}s$, albeit with worse resolution. In addition, corrections
for $\pi^{0}s$ from weak decays from K${}^{0}_{\rm L}$ and $\Lambda$ (together
only about 0.3%) and from secondary hadronic interactions ($2.2$%) were
applied.

##  11 Systematic uncertainties

The sources of systematic uncertainties associated with the various
measurement techniques and their magnitude in different $p_{\mathrm{T}}$
ranges, chosen to reflect the strengths of the various methods, are given in
Tab. 4 for the $\pi^{0}$ meson, in Tab. 5 for $\eta$ meson and in Tab. 6 for
the $\eta/\pi^{0}$ ratio. Since the measurements obtained with PCM-EMC, EMC
and mEMC are a combination of multiple triggers, the systematic uncertainties
associated with each method reflect the contribution of different triggered
data samples weighted by their statistical uncertainties. The uncertainties
for the $\eta/\pi^{0}$ were evaluated directly on the ratio in order to cancel
correlated uncertainties between the $\pi^{0}$ and $\eta$ measurements. In the
following, we first describe the uncertainties on photon candidates
reconstructed with EMC and PCM, then those on the meson level, and finally
those related to the overall normalization, in the same order as given in the
tables.

EMCal clustering:  The uncertainty on clustering quantifies the mismatch in
the description of the clusterization process between data and simulation. It
incorporates the uncertainties arising from the variation of the minimum
energy and time on cluster and cell level, the minimum number of cells per
cluster as well as the variation of the $\sigma^{2}_{\rm long}$ selection on
the clusters. For mEMC, varying the selection on $\sigma^{2}_{\rm long}$ is
especially important since it quantifies the uncertainty of how well the
$\sigma^{2}_{\rm long}$ distributions of the background are described in the
simulation, and was varied from $0.27$ to $0.25$ and $0.3$. The corresponding
uncertainties range between $2.1$% and $6.2$% depending on $p_{\mathrm{T}}$
and method.

EMCal cluster energy calibration:  To estimate the uncertainty of the cluster
energy calibration, the remaining relative difference between data and
simulation in the mass position of the neutral pion was used. On average, the
difference is $0.3$%, which leads to an uncertainty on the spectra of about
$2$% taking into account that they approximately fall with
$p_{\mathrm{T}}^{-6}$. In addition, the correction of the simulations for
relative energy scale and residual misalignment, described in

##  12 sec:diclusterPi0

, was varied by changing the underlying parametrization of the mass position
correction with $p_{\mathrm{T}}$. We chose only correction factors where the
measured neutral pion mass position could be reproduced by the simulation to
better than $1.5$% over all $p_{\mathrm{T}}$. The overall resulting
uncertainties range between $2.0$% and $5.5$% depending on $p_{\mathrm{T}}$
and method. For the $\eta$ meson ($\eta/\pi^{0}$ ratio), the uncertainties are
approximately a factor $1.5$ ($2$) larger at similar $p_{\mathrm{T}}$ due to
lower photon energies entering at the same meson $p_{\mathrm{T}}$.

Track matching to cluster:  The uncertainty introduced by the imperfection of
the cluster-track matching procedure was studied by repeating the measurements
with different track-matching parameters. The criteria were varied from tight
selections, which removed only centrally matched clusters, to rather loose
selections allowing a distance of $2$–$3$ cells depending on $\varphi$ and
$\eta$. At low $p_{\mathrm{T}}$ the uncertainties on the $\pi^{0}$ measurement
are below $2$%, while with increasing $p_{\mathrm{T}}$ higher track densities
due to the jettier environment become more important and lead to uncertainties
of about $7$%. In the case of the $\eta$, the uncertainties are generally
larger, between $4.9$% and $8.9$%, due to the worse signal-to-background
ratio. For the $\eta/\pi^{0}$ ratio, the uncertainty of the $\eta$ alone is
used, since part of the uncertainty is expected to cancel.

$p_{\mathrm{T}}$ interval (GeV/$c$) | 1.4–1.6 | 3.0–3.5 | 16–20 | 30–35
---|---|---|---|---
Method | PCM | P-E | EMC | PCM | P-E | EMC | P-E | EMC | mEMC | mEMC
EMCal clustering | - | 2.4% | 4.9% | - | 2.1% | 2.3% | 6.2% | 4.4% | 4.6% | 5.9%
EMCal energy calib. | - | 2.0% | 4.9% | - | 2.1% | 2.5% | 5.4% | 5.5% | 4.2% | 4.8%
Track matching | - | 0.9% | 1.8% | - | 1.4% | 1.7% | 6.9% | 6.7% | 5.4% | 6.1%
Secondary track reco. | 1.6% | 1.1% | - | 0.9% | 0.8% | - | 5.7% | - | - | -
Electron PID | 1.3% | 0.7% | - | 1.5% | 0.6% | - | 12.7% | - | - | -
PCM photon PID | 1.7% | 1.4% | - | 2.3% | 1.1% | - | 13.4% | - | - | -
Signal extraction | 1.9% | 1.5% | 2.4% | 4.0% | 1.9% | 1.5% | 3.4% | 14.1% | - | -
Efficiency | - | 2.0% | 2.0% | - | 3.6% | 2.5% | 2.1% | 2.1% | 8.4% | 7.1%
Secondary correction | - | - | - | - | - | - | - | - | 1.8% | 1.8%
Inner material | 9.0% | 4.5% | - | 9.0% | 4.5% | - | 4.5% | - | - | -
Outer material | - | 4.2% | 4.2% | - | 4.2% | 4.2% | 4.2% | 4.2% | 4.2% | 4.2%
Trigger norm.+pileup | 0.8% | - | - | 0.4% | 1.1% | 0.5% | 7.5% | 5.5% | 8.0% | 8.8%
Tot. sys. uncertainty | 9.6% | 7.6% | 8.9% | 10.3% | 8.3% | 6.5% | 24.5% | 18.6% | 14.9% | 15.6%
Stat. uncertainty | 2.8% | 2.0% | 6.5% | 5.1% | 3.3% | 2.8% | 14.8% | 15.6% | 5.7% | 11.3%
Table 4: Systematic uncertainty for various sources and methods assigned to
the $\pi^{0}$ measurement at different $p_{\mathrm{T}}$ intervals. For
comparison, the total systematic and the statistical uncertainties are also
given. P-E stands for PCM-EMC.

Secondary track reconstruction:  The uncertainty on the secondary track
reconstruction quantifies the uncertainty related to secondary track finding
used in PCM. It is estimated by variation of the TPC found-over-findable
cluster selection and the minimum $p_{\mathrm{T}}$ cut as well as reducing the
acceptance for the conversion photons in $\varphi_{\rm conv}$ requiring them
to approximately point towards the EMCal direction. The uncertainty depends on
the precision of the relative alignment and track matching efficiency between
TPC and ITS in different sectors of the TPC, and hence can vary for different
data taking periods and trigger conditions. For the EMCal triggers, for
instance, the conversion photons are mainly sampled in the region directly in
front of the EMCal, where the ITS had larger inefficiencies than in other
areas. The uncertainties range from $0.8$% to $5.7$%.

Electron PID:  Systematic uncertainty on the electron identification for the
PCM photon reconstruction was estimated by varying the TPC ${\rm d}E/{\rm
d}x$-based electron inclusion as well as the pion rejection selections. The
corresponding uncertainties are small at low $p_{\mathrm{T}}$ ($\approx 1$%),
where there is good separation between electrons and pions, but reach up to
$12.7$% at high $p_{\mathrm{T}}$, where electrons and pions can not be
efficiently separated any longer.

PCM photon PID:  The uncertainty assigned to the PCM photon reconstruction
combines the contributions from varying the criteria for the photon quality
and Armenteros-Podolanski selections. The uncertainties are slightly larger
than those on the electron PID, with similar $p_{\mathrm{T}}$ dependence,
since both the electron and the photon PID selections attempt to reduce the
contamination which increases with increasing $p_{\mathrm{T}}$. For the
$\eta/\pi^{0}$ ratio, it is one of the dominant uncertainties, in particular
at high $p_{\mathrm{T}}$, as only a small fraction cancels in the ratio due to
the different decay kinematics of the two mesons.

$p_{\mathrm{T}}$ interval (GeV/$c$) | 1–1.5 | 3–4 | 10–12
---|---|---|---
Method | PCM | PCM-EMC | PCM | PCM-EMC | EMC | PCM-EMC | EMC
EMCal clustering | - | 3.1% | - | 3.1% | 2.7% | 3.6% | 3.1%
EMCal energy calib. | - | 3.0% | - | 3.2% | 4.5% | 5.0% | 6.8%
Track matching | - | 8.9% | - | 4.9% | 5.7% | 6.6% | 8.8%
Secondary track reco. | 3.7% | 3.3% | 1.6% | 3.3% | - | 4.1% | -
Electron PID | 2.1% | 2.5% | 2.4% | 2.2% | - | 5.2% | -
PCM photon PID | 3.9% | 7.7% | 3.9% | 7.3% | - | 11.2% | -
Signal extraction | 6.0% | 16.4% | 6.0% | 8.1% | 9.3% | 11.8% | 3.5%
Efficiency | - | 5.0% | - | 5.0% | 5.7% | 5.8% | 5.3%
Inner material | 9.0% | 4.5% | 9.0% | 4.5% | - | 4.5% | -
Outer material | - | 4.2% | - | 4.2% | 4.2% | 4.2% | 4.2%
Trigger norm.+pileup | 1.8% | - | 1.9% | - | 2.8% | 7.0% | 7.2%
Tot. sys. uncertainty | 12.3% | 22.5% | 11.9% | 15.5% | 14.3% | 22.6% | 15.5%
Stat. uncertainty | 20.4% | 43.4% | 17.2% | 16.7% | 10.8% | 21.3% | 8.9%
Table 5: Systematic uncertainty for various sources and methods assigned to the $\eta$ measurement at different $p_{\mathrm{T}}$ intervals. For comparison, the total systematic and the statistical uncertainties are also given. $p_{\mathrm{T}}$ interval (GeV/$c$) | 1–1.5 | 3–4 | 10–12
---|---|---|---
Method | PCM | PCM-EMC | PCM | PCM-EMC | EMC | PCM-EMC | EMC
EMCal clustering | - | 4.1% | - | 4.2% | 2.4% | 6.0% | 2.8%
EMCal energy calib. | - | 4.1% | - | 4.3% | 4.6% | 6.6% | 7.6%
Track matching | - | 8.9% | - | 4.9% | 5.7% | 6.6% | 9.0%
Secondary track reco. | 3.7% | 4.5% | 1.6% | 4.2% | - | 8.1% | -
Electron PID | 2.1% | 3.3% | 2.4% | 3.2% | - | 7.0% | -
PCM photon PID | 3.9% | 7.7% | 4.0% | 6.5% | - | 12.7% | -
Signal extraction | 6.1% | 16.6% | 7.0% | 9.1% | 9.3% | 10.5% | 8.5%
Efficiency | - | 5.4% | - | 5.4% | 3.8% | 7.0% | 4.3%
Tot. sys. uncertainty | 8.4% | 22.5% | 8.5% | 15.6% | 12.6% | 23.8% | 15.4%
Stat. uncertainty | 20.4% | 44.1% | 17.7% | 17.9% | 10.9% | 22.1% | 8.8%
Table 6: Systematic uncertainty for various sources and methods assigned to
the $\eta/\pi^{0}$ measurement at different $p_{\mathrm{T}}$ intervals. For
comparison, the total systematic and the statistical uncertainties are also
given.

Signal extraction:  The uncertainties arising from the signal extraction for
the invariant mass analyses were estimated by varying the integration window,
the background normalization region as well as the minimum opening angle, and
requiring a mild asymmetry of the decay photons. For the neutral pion, the
signal extraction uncertainty for PCM ranges from $1.9$% at low
$p_{\mathrm{T}}$ to $4.0$% at higher $p_{\mathrm{T}}$, due to the good
momentum resolution of the tracks. For PCM-EMC, the equivalent uncertainty
ranges from $1.5$% to $3.4$% at low and high $p_{\mathrm{T}}$, respectively,
while for EMC it ranges from $2.4$% at low to $1.5$% at intermediate and
$14.1$% at high $p_{\mathrm{T}}$. Above $10$ GeV/$c$ the signal extraction
uncertainty for the EMC arises from the merging of the two photon clusters,
and the exact dependence of the corresponding description in the simulation.
For the $\eta$ meson the signal extraction uncertainty generally is larger
since the signal-to-background ratio is smaller, particularly at low
$p_{\mathrm{T}}$. For PCM the uncertainty is $6.0$%, for PCM-EMC it ranges
from $16.4$% to $8.1$% to $11.8$% and for EMC from $9.3$% to $3.5$% GeV/$c$ at
low, intermediate and high $p_{\mathrm{T}}$, respectively. Unlike in the case
of the $\pi^{0}$, the uncertainty for EMC decreases with increasing
$p_{\mathrm{T}}$ since the merging of the clusters for the $\eta$ meson only
sets in at much higher $p_{\mathrm{T}}$ (around $35$ GeV/$c$). For the
$\eta/\pi^{0}$ ratio, the signal extraction uncertainties of the $\pi^{0}$ and
$\eta$ mesons contribute independently.

Efficiency:  The uncertainties on the efficiency were estimated using
different MC generators to vary the input spectrum for the efficiency
calculation, to quantify effects affecting the $p_{\mathrm{T}}$ resolution.
Also, the uncertainties on the modeling of the efficiency bias in the
simulation were included. For PCM-EMC and EMC the uncertainties range from
$2.0$% to $3.6$% depending on $p_{\mathrm{T}}$ for the $\pi^{0}$, while they
are between $5$% and $5.8$% for the $\eta$ meson. For the $\eta/\pi^{0}$
measurement, the uncertainties were added quadratically, without including the
trigger-related uncertainties, which largely cancel. In the case of mEMC, the
uncertainty on the $p_{\mathrm{T}}$ resolution is particularly important,
since it strongly depends on whether the neutral pion could be reconstructed
with all decay particles contributing to the single cluster or just some of
them. To estimate the uncertainty due to a possible imperfection of the MC
simulation in the contribution of the various possibilities, the fractions of
the respective reconstruction possibilities were varied by 20% each, leading
to an uncertainty on the efficiency of $8.4$% at mid ($17$ GeV/$c$) and $7.1$%
at high $p_{\mathrm{T}}$ ($32.5$ GeV/$c$).

Secondary correction:  The correction for secondary $\pi^{0}$ was estimated
applying the efficiency and acceptance from the full ALICE GEANT3 simulation
to a fast MC simulation of the decay kinematics based on the parametrized
K${}^{0}_{S}$ (K${}^{0}_{L}$) and $\Lambda$ spectra [18]. The corresponding
uncertainty was obtained by varying the kaon and $\Lambda$ yield within their
measured uncertainties. Since the correction due to the secondaries is only
$1$–$2$%, for all but the mEMC reconstruction technique, even a variation of
$15$% on the input yields leads to a negligible contribution compared to other
uncertainties. For mEMC, where the correction is about $5$%, an uncertainty of
$\approx 0.5\%$ was obtained. In addition, $\approx 1.5$% were added to the
uncertainty to account for the limited precision in the shape and size of the
correction factors of the full simulations for the pions from K${}^{0}_{S}$,
K${}^{0}_{L}$ and $\Lambda$, which was estimated by varying the
parametrization underlying the efficiencies for secondary $\pi^{0}$.

Inner material:  The uncertainty related to the knowledge of the inner (radius
$<180~{}\mathrm{cm}$) material budget reflects the uncertainty of the
conversion probability of photons, and hence dominantly affects the PCM
measurements. It was estimated to be $4.5\%$ independent of $p_{\mathrm{T}}$
based on detailed comparison between simulation and data for pp collisions at
$\sqrt{s}=7~{}\mathrm{TeV}$ [4]. Thus, it affects the PCM meson measurements
with $9$%, while it only contributes 4.5% to PCM-EMC. In $\eta/\pi^{0}$, the
uncertainty cancels as both mesons are affected in the same way.

Outer material:  For the reconstructed photons in the EMCal, a possible
mismatch between the material present in reality and assumed in the simulation
in front of the EMCal may cause an error in the absorption rate or the
production of secondary pions. In most cases, however, the photon simply
converts and at least one of its daughter electrons can be reconstructed in
the EMCal so that the $\pi^{0}$ likely will be reconstructed as well, although
with degraded $p_{\mathrm{T}}$ resolution. The probability to still
reconstruct the neutral meson increases with increasing conversion radius,
i.e. the closer the conversion happens to the surface of the EMCal. Most of
the material is located at most $1.5$ m away from the EMCal, namely the TPC
outer wall, the Transition Radiation Detector (TRD) and the Time-Of-Flight
(TOF) detector plus their support structures. The TRD was only fully installed
in the LHC shutdown period after 2013. For the 2011 and 2013 data there were
regions in $\varphi$ without TRD modules in front of the EMCal. Hence, the
net-effect of the material in front of the EMCal could be studied by comparing
fully corrected $\pi^{0}$ yields for different $\varphi$ regions with or
without the TRD in front of the EMCal. From the observed difference measured
using the EMC and PCM-EMC measurements, an uncertainty on the neutral meson
yields of $4.2$% independent of $p_{\mathrm{T}}$ was derived, and assigned to
all measurements involving the EMCal. For $\eta/\pi^{0}$ the uncertainty is
assumed to cancel as both mesons should be affected in a similar way.

Trigger normalization and pileup:  The uncertainties for the trigger
normalization were calculated by varying the range for the fit of the plateau
region (see Fig. 1) for the different trigger combinations, leading to the
respective rejection factors with their uncertainties given in Tab. 1. Since
the final spectra for each measurement technique using the EMCal are composed
of several triggers, the contributions of the respective trigger rejection
uncertainties enter the final measurement with different magnitudes depending
on $p_{\mathrm{T}}$. The uncertainties range between $0.5$% and $8.8$%. For
$\eta/\pi^{0}$ the uncertainties cancel as the ratio was measured per trigger
and reconstruction method and combined afterwards. For PCM only minimum bias
triggers were used, and hence no uncertainty due to the trigger rejection was
assigned. However, an uncertainty of $0.8$% to $0.4$% was taken into account
for the out-of-bunch pileup subtraction described in [5]. The pileup
uncertainty is about $1.8$% for the $\eta$ meson. It largely cancels in the
$\eta/\pi^{0}$ ratio, however, and the remaining error can be neglected
compared to other error sources.

Meson |  $\mathbf{A_{e}}$ (pb GeV${}^{-2}c^{3}$) |  $\mathbf{T_{e}}$ (GeV$/c$) |  $\mathbf{A}$ (pb GeV${}^{-2}c^{3}$) |  $\mathbf{T}$ (GeV$/c$) | $\mathbf{n_{\rm br}}$
---|---|---|---|---|---
$\pi^{0}$ | $(0.79\pm 0.35)\cdot 10^{9}$ | $0.566\pm 0.035$ | $(74.3\pm 12.9)\cdot 10^{9}$ | $0.441\pm 0.021$ | $3.083\pm 0.027$
$\eta$ | $(18.5\pm 22.1)\cdot 10^{9}$ | $0.149\pm 0.070$ | $(1.4\pm 1.0)\cdot 10^{9}$ | $0.852\pm 0.136$ | $3.318\pm 0.122$
Table 7: Parameters of the two-component model, Eq. 7 [25, 26], which are used
to parametrize the neutral pion and $\eta$ meson spectra, respectively, for
the comparisons to models and among the different methods.

##  13 Results

Since the meson measurements with PHOS, PCM, EMC, PCM-EMC and mEMC have partly
uncorrelated systematic uncertainties, their combination will increase the
precision of the respective cross section measurements. The BLUE method [27,
28, 29] was used to calculate the combined spectra of the $\pi^{0}$ and $\eta$
mesons as well as the $\eta/\pi^{0}$ ratio. For the combination of the
spectra, the full correlation matrix was taken into account by estimating the
correlated and uncorrelated part of the systematics for all pairs of
measurements versus $p_{\mathrm{T}}$. Correlations are most apparent between
the three EMC related measurements (EMC, PCM-EMCand mEMC), as well as for the
PCM-EMC and PCM results. At high $p_{\mathrm{T}}$, for instance, the
uncertainties are dominated by the uncertainty on $R_{\rm Trig}$ which is
largely common between the EMCal triggered analyses. Uncertainties between
PHOS, PCM, and EMC (mEMC) are uncorrelated. The combined spectra were fitted
with a two-component model (TCM)

$E\frac{\mbox{d}^{3}\sigma}{\mbox{d}p^{3}}=A_{\rm
e}\exp{\frac{(M-\sqrt{p_{\mathrm{T}}^{2}+M^{2}})}{T_{\rm
e}}}+{A}{\left(1+\frac{p_{\mathrm{T}}^{2}}{n_{\rm br}T^{2}}\right)^{-n_{\rm
br}}}$ (7)

introduced by Bylinkin and Rostovtsev [25, 26], which serves as convenient
parametrization of the data without aiming for a physics interpretation. The
parameters for the $\pi^{0}$ and $\eta$ fits are given in Tab. 7 for
$\chi^{2}/n_{\rm dof}$ values of better than $0.5$ taking statistical and
systematic uncertainties in quadrature. Unlike for Tsallis [30] and power-law
distributions, which at high and low $p_{\mathrm{T}}$, respectively,
systematically deviate from the data, the TCM parameterization describes the
data over the full measured range to better than 10%.

Figure 8 shows a comparison of the individual measurements in their respective
measured $p_{\mathrm{T}}$ ranges summarized in Tab. 8 to the two-component
model fits for the $\pi^{0}$ and $\eta$ mesons. As already mentioned above,
the $\pi^{0}$ spectrum in pp collisions at $\sqrt{s}=2.76$ TeV has been
measured by ALICE using the PHOS and PCM [5]. The new results obtained with
the different EMC measurements and with the hybrid PCM-EMC method are
consistent with these earlier results, and the combination with the former
measurements improves the precision of the data. The figure also demonstrates
an approximately fourfold extension of the $p_{\mathrm{T}}$ reach of the
measurement by using the EMCal. The $\eta$ measurement, which is the first
such measurement at $\sqrt{s}=2.76$ TeV, spans from $0.6$ GeV/$c$ to $20$
GeV/$c$. There is good agreement within the statistical uncertainties among
the different detection techniques. Above $p_{\mathrm{T}}>4$ GeV/$c$, the
result is dominated by the EMCal measurements.

Figure 8: Comparison of the individual measurements in their respective measured transverse momentum ranges relative to the two-component model fits [25, 26] of the final spectra. The final spectra are obtained by combining the individual measurements in the overlapping $p_{\mathrm{T}}$ regions with the highest granularity using the full correlation matrix as defined in the BLUE-algorithm [27, 28, 29]. Method | $\pi^{0}$ | $\eta$ | $\eta/\pi^{0}$
---|---|---|---
PCM | 0.4–8.0 | 0.5–6.0 | 0.5–6.0
PHOS | 0.8–12.0 | n/a | n/a
EMC | 1.4–20.0 | 2.0–20.0 | 2.0–20.0
PCM-EMC | 0.8–20.0 | 1.0–16.0 | 1.0–16.0
mEMC | 16.0–40.0 | n/a | n/a
Table 8: Summary of the $p_{\mathrm{T}}$ reach (in GeV/$c$) of the various
reconstruction methods for $\pi^{0}$, $\eta$ and $\eta/\pi^{0}$.

Figure 9: Invariant differential cross section of the $\pi^{0}$ (left, top
panel) and $\eta$ meson (right, top panel) for pp collisions at
$\sqrt{s}=2.76$ TeV. The data are compared to PYTHIA 8.2 [31] generator-level
simulations using the Monash 2013 tune as well as recent NLO pQCD calculations
[3, 6]. The ratios of the data and the calculations to the respective two-
component model fits [25, 26] to the data are shown in the lower panels. The
horizontal error bars denote statistical, the boxes systematic uncertainties.

Figure 9 shows the combined $\pi^{0}$ and $\eta$ cross sections in pp
collisions at $\sqrt{s}=2.76$ TeV, and Fig. 10 the corresponding
$\eta/\pi^{0}$ ratio. As mentioned earlier, the data were parameterized with a
two-component model of Bylinkin and Rostovtsev [26] (see Tab. 7) and compared
to recent NLO pQCD calculations [3, 6], and PYTHIA 8.2 [31] generator-level
simulations using the widely-used Monash 2013 tune [32]. A large fraction of
hadrons at low $p_{\mathrm{T}}$ is produced in pp collisions via soft parton
interactions and from resonance decays, which cannot be well described within
the framework of pQCD, but are taken into account in the event-generator
approach. For the $\pi^{0}$, the pQCD calculation [3], which uses the DSS14
fragmentation functions seems to have a different shape than the data. It
overpredicts the data by about $30$% at intermediate $p_{\mathrm{T}}$ ($5$
GeV/$c$$<p_{\mathrm{T}}<16$ GeV/$c$), while it agrees with the data at higher
$p_{\mathrm{T}}$. The PYTHIA 8.2 calculation describes the data well, except
below $1$ GeV/$c$, where it overpredicts the data by up to $30$%. For
$p_{\mathrm{T}}$ above $15$ GeV/$c$ PYTHIA has a tendency to underpredict the
data by about $10$%; however this slight difference is covered by the
uncertainties of the measurement. For the $\eta$ meson, the data and the NLO
pQCD calculation [6], which uses the AESSS fragmentation functions, agree
within the uncertainties for $\mu=2p_{\mathrm{T}}$ for factorization and
fragmentation scale, while for $\mu=0.5p_{\mathrm{T}}$ the calculation
overpredicts the data by up to a factor of $2$–$3$, leaving room for future
improvements in the understanding of the strange versus non-strange quark
fragmentation functions. The PYTHIA 8.2 simulation with the Monash 2013 tune
performs slightly worse for the $\eta$ than for the $\pi^{0}$, in particular
for $p_{\mathrm{T}}>3$ GeV/$c$ where it underpredicts the data by about
$20$–$30$%. In the $\eta/\pi^{0}$ ratio, parts of the systematic uncertainties
cancel not only for the data but also for the NLO pQCD calculation. Thus, even
the predictions using older fragmentation functions for the $\pi^{0}$ [33] and
the $\eta$ [6], which can not reproduce the individual spectra [5], are in
good agreement for the $\eta/\pi^{0}$ measurement. PYTHIA 8.2 using the Monash
2013 tune can reproduce the $p_{\mathrm{T}}$ dependence of the ratio; however
it underpredicts the ratio by about $20$–$30$% above $3$ GeV/$c$, albeit still
in agreement with the data to within $1$–$2\sigma$. The measured
$\eta/\pi^{0}$ ratio is found to agree with previous measurements in pp
collisions at $\sqrt{s}=0.2$ TeV [34] and $\sqrt{s}=7$ TeV [4] suggesting that
$\eta/\pi^{0}$ is collision-energy independent. Above $4$ GeV/$c$, both mesons
exhibit a similar power-law behavior with $n_{\pi^{0}}=6.29\pm
0.02^{\text{stat}}\pm 0.04^{\text{sys}}$ and $n_{\eta}=6.38\pm
0.09^{\text{stat}}\pm 0.15^{\text{sys}}$ with $\chi^{2}/n_{\rm dof}$ of below
$1.8$. This is also reflected in the $\eta/\pi^{0}$ ratio, which above $4$
GeV/$c$ reaches a value of $0.48\pm 0.02^{\text{stat}}\pm 0.04^{\text{sys}}$.

Figure 10: Measured $\eta/\pi^{0}$ ratio in pp collisions at $\sqrt{s}=2.76$
TeV compared to NLO pQCD calculations [33, 6] and PYTHIA 8.2 [14] generator-
level simulations using the Monash 2013 tune. The horizontal error bars denote
statistical, the boxes systematic uncertainties. The data at $\sqrt{s}=0.2$
TeV [34] and $\sqrt{s}=7$ TeV [4] are shown with statistical and systematic
uncertainties added in quadrature.

##  14 Summary

The invariant differential cross sections for inclusive $\pi^{0}$and $\eta$
production at midrapidity in pp collisions at $\sqrt{s}=2.76$ TeV were
measured over a large range in transverse momentum of $0.4<p_{\mathrm{T}}<40$
GeV/$c$ and $0.6<p_{\mathrm{T}}<20$ GeV/$c$, respectively. To achieve these
measurements, for the $\pi^{0}$ ($\eta$) five (three) different reconstruction
techniques and multiple higher-level triggers involving the EMCal in ALICE
were exploited. In particular, a new single-cluster, shower-shape based method
was developed to identify high-$p_{\mathrm{T}}$ neutral pions whose decay
photons overlap in the EMCal. Above $4$ GeV/$c$, both the $\pi^{0}$ and $\eta$
cross sections are found to exhibit a similar power-law behavior with an
exponent of about $6.3$. The data were compared to state-of-the-art NLO pQCD
calculations which are found to reproduce the neutral pion cross section
within $30\%$, while the deviations for the $\eta$ meson are significantly
larger. Calculations using PYTHIA 8.2 at generator-level with the Monash 2013
tune turn out to be consistent with the $\pi^{0}$ measurement, except below
$1$ GeV/$c$, where the calculation overpredicts the data by up to $50$%. For
the $\eta$, the agreement is slightly worse than for the $\pi^{0}$, in
particular for $p_{\mathrm{T}}>3$ GeV/$c$ where the calculation underpredicts
the data by about $20$–$30$%. The $\eta/\pi^{0}$ ratio, which was found to be
described by the calculations to within $1$–$2\sigma$, is $0.48\pm
0.02^{\text{stat}}\pm 0.04^{\text{sys}}$ above $4$ GeV/$c$, consistent with
previous measurements. The new data provide significant constraints for future
calculations of hadron spectra over a large range in $p_{\mathrm{T}}$.

## Acknowledgments

We thank Werner Vogelsang and Marco Stratmann for providing us with their
calculations.

The ALICE Collaboration would like to thank all its engineers and technicians for their invaluable contributions to the construction of the experiment and the CERN accelerator teams for the outstanding performance of the LHC complex. The ALICE Collaboration gratefully acknowledges the resources and support provided by all Grid centres and the Worldwide LHC Computing Grid (WLCG) collaboration. The ALICE Collaboration acknowledges the following funding agencies for their support in building and running the ALICE detector: A. I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Foundation (ANSL), State Committee of Science and World Federation of Scientists (WFS), Armenia; Austrian Academy of Sciences and Nationalstiftung für Forschung, Technologie und Entwicklung, Austria; Ministry of Communications and High Technologies, National Nuclear Research Center, Azerbaijan; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Universidade Federal do Rio Grande do Sul (UFRGS), Financiadora de Estudos e Projetos (Finep) and Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), Brazil; Ministry of Science & Technology of China (MSTC), National Natural Science Foundation of China (NSFC) and Ministry of Education of China (MOEC) , China; Ministry of Science, Education and Sport and Croatian Science Foundation, Croatia; Ministry of Education, Youth and Sports of the Czech Republic, Czech Republic; The Danish Council for Independent Research | Natural Sciences, the Carlsberg Foundation and Danish National Research Foundation (DNRF), Denmark; Helsinki Institute of Physics (HIP), Finland; Commissariat à l’Energie Atomique (CEA) and Institut National de Physique Nucléaire et de Physique des Particules (IN2P3) and Centre National de la Recherche Scientifique (CNRS), France; Bundesministerium für Bildung, Wissenschaft, Forschung und Technologie (BMBF) and GSI Helmholtzzentrum für Schwerionenforschung GmbH, Germany; Ministry of Education, Research and Religious Affairs, Greece; National Research, Development and Innovation Office, Hungary; Department of Atomic Energy Government of India (DAE) and Council of Scientific and Industrial Research (CSIR), New Delhi, India; Indonesian Institute of Science, Indonesia; Centro Fermi - Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi and Istituto Nazionale di Fisica Nucleare (INFN), Italy; Institute for Innovative Science and Technology , Nagasaki Institute of Applied Science (IIST), Japan Society for the Promotion of Science (JSPS) KAKENHI and Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan; Consejo Nacional de Ciencia (CONACYT) y Tecnología, through Fondo de Cooperación Internacional en Ciencia y Tecnología (FONCICYT) and Dirección General de Asuntos del Personal Academico (DGAPA), Mexico; Nationaal instituut voor subatomaire fysica (Nikhef), Netherlands; The Research Council of Norway, Norway; Commission on Science and Technology for Sustainable Development in the South (COMSATS), Pakistan; Pontificia Universidad Católica del Perú, Peru; Ministry of Science and Higher Education and National Science Centre, Poland; Korea Institute of Science and Technology Information and National Research Foundation of Korea (NRF), Republic of Korea; Ministry of Education and Scientific Research, Institute of Atomic Physics and Romanian National Agency for Science, Technology and Innovation, Romania; Joint Institute for Nuclear Research (JINR), Ministry of Education and Science of the Russian Federation and National Research Centre Kurchatov Institute, Russia; Ministry of Education, Science, Research and Sport of the Slovak Republic, Slovakia; National Research Foundation of South Africa, South Africa; Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Cubaenergía, Cuba, Ministerio de Ciencia e Innovacion and Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Spain; Swedish Research Council (VR) and Knut & Alice Wallenberg Foundation (KAW), Sweden; European Organization for Nuclear Research, Switzerland; National Science and Technology Development Agency (NSDTA), Suranaree University of Technology (SUT) and Office of the Higher Education Commission under NRU project of Thailand, Thailand; Turkish Atomic Energy Agency (TAEK), Turkey; National Academy of Sciences of Ukraine, Ukraine; Science and Technology Facilities Council (STFC), United Kingdom; National Science Foundation of the United States of America (NSF) and United States Department of Energy, Office of Nuclear Physics (DOE NP), United States of America.

## References

  * [1] D. J. Gross and F. Wilczek, “Asymptotically free Gauge theories,” Phys. Rev. D8 (1973) 3633–3652.
  * [2] CTEQ Collaboration, G. Sterman, J. Smith, J. C. Collins, J. Whitmore, R. Brock, J. Huston, J. Pumplin, W.-K. Tung, H. Weerts, C.-P. Yuan, S. Kuhlmann, S. Mishra, J. G. Morfín, F. Olness, J. Owens, J. Qiu, and D. E. Soper, “Handbook of perturbative QCD,” Rev. Mod. Phys. 67 (Jan, 1995) 157–248. http://link.aps.org/doi/10.1103/RevModPhys.67.157.
  * [3] D. de Florian, R. Sassot, M. Epele, R. J. Hernández-Pinto, and M. Stratmann, “Parton-to-pion fragmentation reloaded,” Phys. Rev. D91 no. 1, (2015) 014035, arXiv:1410.6027 [hep-ph].
  * [4] ALICE Collaboration, B. Abelev et al., “Neutral pion and $\eta$ meson production in proton-proton collisions at $\sqrt{s}=0.9$ TeV and $\sqrt{s}=7$ TeV,” Phys. Lett. B717 (2012) 162–172, arXiv:1205.5724 [hep-ex].
  * [5] ALICE Collaboration, B. B. Abelev et al., “Neutral pion production at midrapidity in pp and Pb–Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV,” Eur. Phys. J. C74 no. 10, (2014) 3108, arXiv:1405.3794 [nucl-ex].
  * [6] C. A. Aidala, F. Ellinghaus, R. Sassot, J. P. Seele, and M. Stratmann, “Global analysis of fragmentation functions for $\eta$ mesons,” Phys. Rev. D83 (2011) 034002, arXiv:1009.6145 [hep-ph].
  * [7] ALICE Collaboration, K. Aamodt et al., “The ALICE experiment at the CERN LHC,” JINST 3 (2008) S08002.
  * [8] ALICE Collaboration, B. B. Abelev et al., “Performance of the ALICE Experiment at the CERN LHC,” Int. J. Mod. Phys. A29 (2014) 1430044, arXiv:1402.4476 [nucl-ex].
  * [9] J. Alme et al., “The ALICE TPC, a large 3-dimensional tracking device with fast readout for ultra-high multiplicity events,” Nucl. Instrum. Meth. A622 (2010) 316–367, arXiv:1001.1950 [physics.ins-det].
  * [10] ALICE Collaboration, K. Aamodt et al., “Alignment of the ALICE Inner Tracking System with cosmic-ray tracks,” JINST 5 (2010) P03003, arXiv:1001.0502 [physics.ins-det].
  * [11] ALICE Collaboration, P. Cortese et al., “ALICE electromagnetic calorimeter technical design report,”.
  * [12] ALICE EMCal Collaboration, U. Abeysekara et al., “ALICE EMCal Physics Performance Report,” arXiv:1008.0413 [physics.ins-det].
  * [13] ALICE Collaboration, B. Abelev et al., “Measurement of inelastic, single- and double-diffraction cross sections in proton–proton collisions at the LHC with ALICE,” Eur. Phys. J. C73 no. 6, (2013) 2456, arXiv:1208.4968 [hep-ex].
  * [14] T. Sjostrand, S. Mrenna, and P. Z. Skands, “A brief introduction to PYTHIA 8.1,” Comput. Phys. Commun. 178 (2008) 852–867, arXiv:0710.3820 [hep-ph].
  * [15] R. Engel, J. Ranft, and S. Roesler, “Hard diffraction in hadron hadron interactions and in photoproduction,” Phys. Rev. D52 (1995) 1459–1468, arXiv:hep-ph/9502319 [hep-ph].
  * [16] T. Sjostrand, S. Mrenna, and P. Z. Skands, “PYTHIA 6.4 Physics and Manual,” JHEP 05 (2006) 026, arXiv:hep-ph/0603175 [hep-ph].
  * [17] R. Brun, F. Bruyant, M. Maire, A. McPherson, and P. Zanarini, “GEANT3,”.
  * [18] ALICE Collaboration, B. B. Abelev et al., “Production of charged pions, kaons and protons at large transverse momenta in pp and Pb–Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV,” Phys. Lett. B736 (2014) 196–207, arXiv:1401.1250 [nucl-ex].
  * [19] G. D. Lafferty and T. R. Wyatt, “Where to stick your data points: The treatment of measurements within wide bins,” Nucl. Instrum. Meth. A355 (1995) 541–547.
  * [20] J. Podolanski and R. Armenteros, “III. Analysis of V-events,” Philosophical Magazine 45 no. 360, (1954) 13–30.
  * [21] T. Awes, F. Obenshain, F. Plasil, S. Saini, S. Sorensen, and G. Young, “A simple method of shower localization and identification in laterally segmented calorimeters,” Nucl.Instrum.Method A311 no. 1, (1992) 130–138.
  * [22] G. I. Kopylov, “Like particle correlations as a tool to study the multiple production mechanism,” Phys. Lett. B50 (1974) 472–474.
  * [23] L. E. Gordon and W. Vogelsang, “Polarized and unpolarized prompt photon production beyond the leading order,” Phys. Rev. D48 (1993) 3136–3159.
  * [24] W. Vogelsang and M. R. Whalley, “A Compilation of data on single and double prompt photon production in hadron hadron interactions,” J. Phys. G23 (1997) A1–A69.
  * [25] A. A. Bylinkin and A. A. Rostovtsev, “Role of quarks in hadroproduction in high energy collisions,” Nucl. Phys. B888 (2014) 65–74, arXiv:1404.7302 [hep-ph].
  * [26] A. A. Bylinkin and M. G. Ryskin, “Secondary hadron distributions in two component model,” Phys. Rev. D90 no. 1, (2014) 017501, arXiv:1404.4739 [hep-ph].
  * [27] L. Lyons, D. Gibaut, and P. Clifford, “How to Combine Correlated Estimates of a Single Physical Quantity,” Nucl.Instrum.Meth. A270 (1988) 110.
  * [28] A. Valassi, “Combining correlated measurements of several different physical quantities,” Nucl.Instrum.Meth. A500 (2003) 391–405.
  * [29] A. Valassi and R. Chierici, “Information and treatment of unknown correlations in the combination of measurements using the BLUE method,” Eur.Phys.J. C74 (2014) 2717, arXiv:1307.4003 [physics.data-an].
  * [30] C. Tsallis, “Possible generalization of Boltzmann-Gibbs statistics,” J. Statist. Phys. 52 (1988) 479–487.
  * [31] T. Sjöstrand, S. Ask, J. R. Christiansen, R. Corke, N. Desai, P. Ilten, S. Mrenna, S. Prestel, C. O. Rasmussen, and P. Z. Skands, “An Introduction to PYTHIA 8.2,” Comput. Phys. Commun. 191 (2015) 159–177, arXiv:1410.3012 [hep-ph].
  * [32] P. Skands, S. Carrazza, and J. Rojo, “Tuning PYTHIA 8.1: the Monash 2013 Tune,” Eur. Phys. J. C74 no. 8, (2014) 3024, arXiv:1404.5630 [hep-ph].
  * [33] D. de Florian, R. Sassot, and M. Stratmann, “Global analysis of fragmentation functions for pions and kaons and their uncertainties,” Phys. Rev. D75 (2007) 114010, arXiv:hep-ph/0703242 [HEP-PH].
  * [34] PHENIX Collaboration, A. Adare et al., “Cross section and double helicity asymmetry for $\eta$ mesons and their comparison to neutral pion production in p+p collisions at $sqrt(s)=200GeV$,” Phys. Rev. D83 (2011) 032001, arXiv:1009.6224 [hep-ex].

##  Appendix A The ALICE Collaboration

S. Acharya${}^{\textrm{\scriptsize 139}}$, D. Adamová${}^{\textrm{\scriptsize
87}}$, M.M. Aggarwal${}^{\textrm{\scriptsize 91}}$, G. Aglieri
Rinella${}^{\textrm{\scriptsize 34}}$, M. Agnello${}^{\textrm{\scriptsize
30}}$, N. Agrawal${}^{\textrm{\scriptsize 47}}$, Z.
Ahammed${}^{\textrm{\scriptsize 139}}$, N. Ahmad${}^{\textrm{\scriptsize
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