Exclusive $\mathrm{J/}\psi$ photoproduction off protons in ultra-peripheral p-Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV

arXiv:1406.7819v2 [nucl-ex] 14 Jul 2015

CERN-PH-EP-2014-149

22 June 2014

c

2014 CERN for the benefit of the ALICE Collaboration.

Reproduction of this article or parts of it is allowed as specified in the CC-BY-3.0 license.

Exclusive J/

ψ

photoproduction off protons

in ultra-peripheral p–Pb collisions at

√

s

_NN

=5.02 TeV

ALICE Collaboration

∗

Abstract

We present the first measurement at the LHC of exclusive J/ψ photoproduction off protons, in ultra-peripheral proton-lead collisions at√sNN= 5.02 TeV. Events are selected with a dimuon pair

pro-duced either in the rapidity interval, in the laboratory frame, 2_{.5 < y < 4 (p–Pb) or −3.6 < y < −2.6} (Pb–p), and no other particles observed in the ALICE acceptance. The measured cross sections

σ(γ+ p → J/ψ+ p) are 33.2 ± 2.2 (stat) ± 3.2 (syst) ± 0.7 (theo) nb in p–Pb and 284 ± 36 (stat)

+27

−32(syst)± 26 (theo) nb in Pb–p collisions. We measure this process up to about 700 GeV in the γp centre-of-mass, which is a factor of two larger than the highest energy studied at HERA. The data are consistent with a power law dependence of the J/ψphotoproduction cross section inγp energies from about 20 to 700 GeV, or equivalently, from Bjorken-x between_{∼ 2 × 10}−2to_{∼ 2 × 10}−5, thus indicating no significant change in the gluon density behaviour of the proton between HERA and LHC energies.

Exclusive J

/

ψ

photoproduction off protons is defined by a reaction in which the J

/

ψ

is produced from

a

γ

p interaction, where the proton emerges intact:

γ

+ p → J/

ψ

+ p. This process allows a detailed

study of the gluon distribution in the proton, since its cross section is expected to scale as the square

of the gluon probability density function (PDF), according to leading order QCD calculations [1]. The

mass of the charm quark provides an energy scale large enough to allow perturbative QCD calculations,

albeit with some theoretical uncertainties [2]. This process provides a powerful tool to search for gluon

saturation [3, 4], which is the most straightforward mechanism to slow down the growth of the PDF for

gluons carrying a small fraction of the momentum of hadrons (Bjorken-x). Finding evidence of gluon

saturation has become a central task for present experiments and for future projects [5, 6] that aim to

study Quantum Chromo-Dynamics (QCD).

Both ZEUS and H1 measured the exclusive J

/

ψ

photoproduction off protons at

γ

p centre-of-mass

ener-gies ranging from 20 to 305 GeV [7, 8, 9]. This process has also been studied in pp [10], p¯p [11] and

heavy-ion collisions [12, 13, 14].

In this Letter we present the first measurement of exclusive J

/

ψ

photoproduction in collisions of protons

with Pb nuclei at centre-of-mass energy per nucleon pair

√

s

NN

= 5.02 TeV. The J/

ψ

is produced by the

interaction of a photon with either a proton or a nuclear target, where the photon is emitted from one of

the two colliding particles. Although both

γ

_{+ p → J/}

ψ

+ p and

γ

_{+ Pb → J/}

ψ

+ Pb can occur, the Pb

electric charge makes the photon emission by ion to be strongly enhanced with respect to that from the

proton [15, 16].

The main ALICE detector used in this analysis is the single-arm muon spectrometer [17], covering the

pseudorapidity interval

_{−4.0 <}

η

_{< −2.5. The beam directions of the LHC were reversed in order to}

measure both forward and backward rapidity. Thus, J

/

ψ

s are reconstructed in the 2

.5 < y < 4.0 (p–Pb)

and

_{−3.6 < y < −2.6 (Pb–p) rapidity intervals, where y is measured in the laboratory frame with respect}

to the proton beam direction

1

. The

γ

p centre-of-mass energy W

_γp

is determined by the J

/

ψ

rapidity:

W

_γ2_p

= 2E

p

M

J/ψ

exp

(−y), where M

J/ψ

is the J

/

ψ

mass, y is the J

/

ψ

rapidity and E

p

is the proton energy

(E

p

= 4 TeV in the lab frame), while the Bjorken-x is given by x = (M

J/ψ

/W

γp

)

2

. We study 21

< W

γp

< 45

GeV for y

> 0 and 577 < W

_γp

< 952 GeV for y < 0, thereby exceeding the

γ

p range of HERA.

The muon spectrometer consists of a ten interaction length absorber, followed by five tracking stations,

each made of two planes of cathode pad chambers, with the third station placed inside a dipole magnet

with a 3 T

_{·m integrated magnetic field. The muon trigger system, downstream of the tracking chambers,}

consists of four planes of resistive plate chambers placed behind a 7.2 interaction length iron wall. The

single muon trigger threshold for the data used in this analysis was set to transverse momentum p

T

=

0.5 GeV/c. Other detectors used in this analysis are the Silicon Pixel Detector (SPD), VZERO and Zero

Degree Calorimeters (ZDC) [17]. The central region

_|

η

_{| < 1.4 is covered by the SPD consisting of two}

cylindrical layers of silicon pixels. The pseudorapidity interval 2

.8 <

η

< 5.1 is covered by VZERO-A

and

_{−3.7 <}

η

_{< −1.7 by VZERO-C. These detectors are scintillator tile arrays with a time resolution}

better than 1 ns, allowing us to distinguish between beam-beam and beam-gas interactions. The two

ZDCs are located at

_{±112.5 m from the interaction point, and are used to detect neutrons and protons}

emitted in the very forward region.

The trigger for the p–Pb configuration required two oppositely charged tracks in the muon spectrometer,

and a veto on VZERO-A beam-beam interactions. In the Pb–p configuration, the trigger purity was

improved with respect to the p–Pb by suppressing beam-induced backgrounds. This was achieved by

requiring at least one hit in VZERO-C beam-beam trigger and a veto on VZERO-A beam-gas trigger.

The integrated luminosity L was corrected for the probability that exclusivity requirements could be

1_{The ALICE detector acceptance is given in the laboratory pseudorapidityη. The convention in ALICE is that the muon}

spectrometer is located atη< 0. In contrast, the laboratory rapidity y will change sign according to the proton beam direction,

spoiled by multiple interactions in the same bunch crossing. This pile-up correction is on average 5%,

giving L = 3.9 nb

−1

± 3.7% (syst) for p–Pb and L = 4.5 nb

−1

_{± 3.4% (syst) for Pb–p data [18].}

Events with exactly two reconstructed tracks in the muon spectrometer were selected offline. The muon

tracks had to fulfill the requirements on the radial coordinate of the track at the end of the absorber and

on the extrapolation to the nominal vertex, as described in [12, 19]. Both track pseudorapidities were

required to be within the chosen range

_{−4.0 <}

η

track

< −2.5 for p–Pb and −3.7 <

η

track

< −2.5 for Pb–

p. Track segments in the tracking chambers must be matched with corresponding segments in the trigger

chambers. The dimuon rapidity was in the range 2

_{.5 < y < 4.0 for p–Pb and −3.6 < y < −2.6 for Pb–p.}

The chosen range in Pb–p ensured that the muon tracks are in the overlap of the muon spectrometer

and VZERO-C geometrical acceptance, as VZERO-C was part of the trigger in Pb-p. A cut on VZERO

timing was imposed offline to be compatible with crossing beams. In order to reduce contamination

from non-exclusive J

/

ψ

s that come mainly from proton dissociation, only events with no mid-rapidity

tracklets (track segments formed by two hits at each SPD layer) were kept. For the same reasons, events

with neutron or proton activity in any of the ZDCs were rejected.

The dimuon invariant mass spectra (M

_µ+_µ−) after these selections are shown in Fig. 1. The J

/

ψ

peak

is clearly visible in both data sets, and is well described by a Crystal Ball parametrization [20], which

yields masses and widths in agreement with the Monte Carlo simulations. The dimuon continuum is

well described by an exponential as expected from two-photon production of continuum pairs (

γγ

_→

µ

+

_µ

−

_{) [12, 13].}

The extracted number of J

/

ψ

s obtained from the invariant mass fit includes a mix of exclusive and

non-exclusive J/

ψ

candidates. A different p

T

distribution is expected from exclusive and non-exclusive

J/

ψ

events [9]. For this reason, the number of exclusive J/

ψ

s can be determined from the dimuon p

T

distributions shown in Fig. 2. The bulk of dimuon events having p

T

< 1 GeV/c is mainly due to exclusive

J

/

ψ

production, while the tail extending up to higher p

T

on the top panel (p–Pb) comes from

non-exclusive interactions. Exclusive J

/

ψ

coming from

γ

p interactions and

γγ

contribute to both p

T

spectra.

In addition, for p–Pb, a background, coming from non-exclusive J

/

ψ

s and non-exclusive

γγ

_→

µ

+

µ

−

events was taken into account, while for the Pb–p sample a contribution from coherent J

/

ψ

in

γ

Pb

interactions was considered. The latter process was neglected in p–Pb as it amounts to less than 2% [16].

If modifications to the nuclear gluon distribution, also known as nuclear shadowing, are considered this

contribution would be even smaller. Here, an additional 50% reduction is expected [13] from shadowing

effects. The p

T

shapes for the J

/

ψ

in

γ

p,

γγ

→

µ

+

µ

−

, and coherent J

/

ψ

in

γ

Pb components (Monte

Carlo templates) were obtained using STARLIGHT [21, 22] events folded with the detector response

simulation. For p–Pb, these templates were fitted to the data leaving the normalization free for J

/

ψ

in

γ

p

and the non-exclusive background. The

γγ

_→

µ

+

µ

−

component was constrained from the invariant mass

fit shown in Fig. 1 [12]. The non-exclusive contributions were subtracted using this fitting procedure,

giving N

J/ψ

.

The p

T

distribution of non-exclusive J

/

ψ

candidates and the non-exclusive dimuon continuum were

obtained from data, using the same event selection as above, but requiring events to have more than two

hits in the VZERO-C counters. At HERA the ratio of the non-exclusive J/

ψ

production cross section

to the exclusive one was found to decrease with W

γp

[9]. Extrapolating, this means a factor 2 smaller

non-exclusive J

/

ψ

contribution in the Pb–p sample. We note that for this sample dissociation products

went towards VZERO-A, used as veto at the trigger level, providing an explanation on the negligible

non-exclusive contribution observed.

The number of exclusive J

/

ψ

coming from

γ

p interactions (N

_Jexc_/ψ

) was obtained as N

_Jexc_/ψ

= N

J/ψ

/(1 + f

D

),

where f

D

is the fraction of J

/

ψ

mesons coming from the decay of

ψ

(2S). Following the procedure

described in [12, 13], we obtained f

D

= 7.9

+2.4_−1.9

% (syst) in p–Pb and f

D

= 11

+3.6_−2.8

% (syst) in Pb–p. The

)

2

Dimuon candidates / (50 MeV/c

20

40

60

80

100

120

140

160

180

200

ALICE

2.5<y<4.0

= 5.02 TeV

NN

s

p-Pb

)

2

( GeV/c

-µ + µ

M

1.5

2

2.5

3

3.5

4

4.5

5

0

5

10

15

20

25

30

ALICE

-3.6<y<-2.6

= 5.02 TeV

NN

s

Pb-p

Fig. 1: Invariant mass distribution for events with two oppositely charged muons, for both forward (top panel) and

Dimuon candidates / (100 MeV/c)

20

40

60

80

100

= 5.02 TeV

NN

s

ALICE p-Pb

2.5<y<4.0

2

<3.3 GeV/c

-µ + µ

2.8<M

(GeV/c)

T

Dimuon p

0

0.5

1

1.5

2

2.5

3

3.5

4

0

5

10

15

20

25

Sum

ψ

Exclusive J/

Non-exclusive background

-µ

+

µ

→

γ

γ

+Pb

γ

= 5.02 TeV

NN

s

ALICE Pb-p

-3.6<y<-2.6

2

<3.3 GeV/c

-µ + µ

2.8<M

Fig. 2: Transverse momentum distribution for events with two oppositely charged muons, for both forward (top

Source

p–Pb

Pb–p

Signal extraction

6%

+0.0_−6.0

%

Luminosity [18]

3.3%

3.0%

Tracking efficiency [19]

4%

6%

Muon Trigger efficiency [19]

2.8%

3.2%

Matching

1%

1%

VZERO-C efficiency

-

3.5%

Total uncorrelated

8.5%

_−10.2+8.3

%

Luminosity [18]

1.6%

1.6%

Branching ratio [25]

1%

1%

VZERO-A veto efficiency

+2.0_−0.0

%

+2.0_−0.0

%

Feed-down

+1.8_−2.2

%

+2.6_−3.1

%

J

/

ψ

acceptance

3%

3%

Total

_±9.6%

+9.6_−11.3

%

Table 1: Summary of the contributions to the systematic uncertainty for the integrated J/ψcross section measure-ment for the full rapidity intervals.

proton-nucleus collisions [23, 24]. The resulting yield is N

_Jexc_/ψ

(p–Pb) = 414

_{± 28 (stat) ± 27 (syst).}

N

_Jexc_/ψ

in the Pb–p sample was obtained by event counting, and then subtracting the

γγ

and the

γ

Pb

compo-nents as well as the feed-down from

ψ

(2S) decays. Based on our recent coherent J/

ψ

results in

γ

Pb [12],

taking into account the difference in the centre-of-mass energy, we estimated that 7

_{± 2 (stat) events are}

expected in this sample. We obtained N

_Jexc_/ψ

(Pb–p) = 71

_{± 9 (stat)}

+2₋₅

(syst). A compatible number for

N

exc

J/ψ

was found studying the J

/

ψ

p

T

(see Fig. 2 bottom panel). The exclusive J

/

ψ

template was obtained

by changing the exponential slope of the p

2_T

spectrum in the Monte Carlo from its default value of 4.0 to

6.7 (GeV/c)

−2

. This value agrees with an extrapolation of the W

γp

dependence of the p

2_T

slope seen by

H1 [9].

The product of the detector acceptance and efficiency A

_×

ε

for J

/

ψ

was calculated using STARLIGHT

and ranges from 11% to 31% for the rapidity intervals corresponding to the measurements given in

Table 2. The systematic uncertainties on the measurement of the J

/

ψ

cross section are listed in Table 1.

The cross sections corresponding to exclusive J

/

ψ

photoproduction off protons were obtained using

dσ dy

=

N_Jexc_/ψ

(A×ε)·BR·L·∆y

, where BR is the branching ratio and

∆

y is the rapidity interval. We obtained

dσ dy

= 6.42

_{± 0.43 (stat) ± 0.61 (syst)}

µ

b for p–Pb and

d_dyσ

= 2.46

_{± 0.31 (stat)}

+0.24_−0.28

(syst)

µ

b for Pb–p

collisions (see Table 2).

We measured the cross section for the exclusive

γγ

_→

µ

+

µ

−

process at invariant mass 1

.5 < M

_µ+_µ−

< 2.5

GeV/c

2

and in the rapidity range 2

.5 < y < 4.0, using the same technique as for the J/

ψ

to remove the

non-exclusive background, obtaining

σ

(

γγ

_→

µ

+

µ

−

_{) = 1.76 ± 0.12 (stat) ± 0.16 (syst)}

µ

b for this

kinematic range. The STARLIGHT prediction for this standard QED process is 1.8

µ

b, which is in

good agreement with this measurement. This provides an additional indication that the non-exclusive

background subtraction is under control.

The cross section

d_dyσ

_{(p + Pb → p + Pb + J/}

ψ

) is related to the photon-proton cross section,

σ

(

γ

_{+ p →}

J

/

ψ

_{+ p) ≡}

σ

(W

_γp

), through the photon flux,

dn_dk

:

d

σ

dy

(p + Pb → p + Pb + J/

ψ

) = k

dn

dk

σ

(

γ

+ p → J/

ψ

+ p).

Here, k is the photon energy, which is determined by the J

/

ψ

mass and rapidity, k

= (1/2)M

J/ψ

exp

(−y).

Rapidity d_dyσ(µb) kdn_dk Wγp(GeV) hWγpi (GeV) σ(γ+ p → J/ψ+ p)(nb)

2.5< y <4.0 6.42± 0.43 (stat) ± 0.61 (syst) 193.3 (21,45) 29.8 33.2± 2.2 (stat) ± 3.2 (syst) ± 0.7 (theo)

3.5< y <4.0 5.77± 0.76 (stat) ± 0.58 (syst) 208.9 (21,27) 24.1 27.6± 3.6 (stat) ± 2.8 (syst) ± 0.6 (theo)

3.0< y <3.5 6.71± 0.60 (stat) ± 0.55 (syst) 193.3 (27,35) 30.9 34.7± 3.1 (stat) ± 2.9 (syst) ± 0.7 (theo)

2.5< y < 3.0 6.83± 1.0 (stat) ± 0.75 (syst) 177.6 (35,45) 39.6 38.5± 5.6 (stat) ± 4.2 (syst) ± 0.8 (theo)

-3.6< y < -2.6 2.46_{± 0.31 (stat)}+0.24_−0.28(syst) 8.66 (577,952) 706 284_{± 36 (stat)}+27₋₃₂(syst)_{± 26 (theo)}

Table 2: Differential cross sections for exclusive J/ψ photoproduction off protons in ultra-peripheral p–Pb and Pb–p collisions at√sNN= 5.02 TeV. The corresponding J/ψ photoproduction cross sections in bins of Wγpare

also presented.

and are listed in Table 2. The

_hW

_γp

i is calculated by weighting with the product of the photon spectrum

and the cross section

σ

(

γ

p

) from STARLIGHT. The photon spectrum is calculated in impact parameter

space requiring that there should be no hadronic interaction. The uncertainty in this approach is estimated

by increasing/decreasing the Pb-radius with

_{±0.5 fm, corresponding to the nuclear skin thickness and of}

the same order as the upper limit for the difference between the proton and neutron radius of Pb when

calculating the hadronic interaction probability. This gives an uncertainty of 9% in the photon flux for

the high energy data point and 2% at low energy (see Table 2). The uncertainty is larger for the high

photon energies since here one is dominated by small impact parameters and thus more sensitive to the

rejection of hadronic interactions with impact parameters near the Pb radius.

Figure 3 shows the ALICE measurements for

σ

(W

_γp

). Comparisons to previous measurements and to

different theoretical models are also shown. As mentioned earlier,

σ

(W

γp

) is proportional to the square

of the gluon PDF of the proton [1]. For HERA energies, the gluon distribution at low Bjorken-x is well

described by a power law in x [26], which implies the cross section

σ

(W

_γp

) will also follow a power

law. A deviation from such a trend in the measured cross section as x decreases, or equivalently, as W

γp

increases, could indicate a change in the evolution of the gluon density function, as expected at the onset

of saturation.

Both ZEUS and H1 [7, 8, 9] fitted their data using a power law

σ

_{∼ W}

_γδ_p

, obtaining

δ

= 0.69

_{± 0.02}

(stat)

_{± 0.03 (syst), and}

δ

= 0.67

_{± 0.03 (stat + syst), respectively. Due to the large HERA statistics,}

a simultaneous fit of H1, ZEUS, ALICE low energy points data gives power-law fit parameters almost

identical to those obtained from HERA alone. A fit to ALICE data alone gives

δ

= 0.68

_{± 0.06 (stat +}

syst), only uncorrelated systematic errors were considered here. Thus, no deviation from a power law is

observed up to about 700 GeV.

Two calculations are available from the JMRT group [27]: the first one referred to as LO is based on a

power law description of the process, while the second model is labeled as NLO, and includes

contribu-tions which mimic effects expected from the dominant NLO correccontribu-tions. Because both JMRT models

have been fitted to the same data, the resulting energy dependences are very similar. Our data support

their extracted gluon distribution up to x

_{∼ 2 × 10}

−5

. The STARLIGHT parameterization is based on

a power law fit using only fixed-target and HERA data, giving

δ

= 0.65

± 0.02. Figure 3 also shows

predictions from the b-Sat eikonalized model [28] which uses the Color Glass Condensate approach [29]

to incorporate saturation, constraining it to HERA data alone. The results from the models mentioned

above are within one sigma of our measurement. The b-Sat 1-Pomeron prediction taken from [5] also

agrees with the ALICE low energy data points, but it is about 4 sigmas above our measurement at the

highest energy.

LHCb recently published results for

σ

(W

γp

) based on exclusive J/

ψ

production in pp collisions [10].

Their analysis, using data from a symmetric system, suffers from the intrinsic impossibility of identifying

the photon emitter and the photon target. Since the non-exclusive background, as mentioned above,

depends on W

γp

, this feeds into the uncertainty in the subtraction of these processes, making the extraction

of the underlying

σ

(W

γp

) to be strongly model dependent. Moreover, in contrast with p–Pb collisions,

(GeV)

p γ

W

2

10

10

3

+p) (nb)

ψ

J/

→

+p

γ

(

σ

10

2

10

3

10

ALICE (p-Pb)

ALICE (Pb-p)

Power law fit to ALICE data

H1

ZEUS

JMRT LO

JMRT NLO

b-Sat (eikonalized)

b-Sat (1-Pomeron)

STARLIGHT parameterization

Fig. 3: Exclusive J/ψ photoproduction cross section off protons measured by ALICE and compared to HERA data. Comparisons to STARLIGHT, JMRT and the b-Sat models are shown. The power law fit to ALICE data is also shown.

contribution from production through Odderon-Pomeron fusion [11, 23]. For each

d_dyσ

measurement, they

reported a W

_{+ and a W− solution. These coupled solutions are shown in Figure 4, together with the}

power law fit to ALICE measurements. Despite these ambiguities and assumptions the LHCb solutions

turned out to be compatible with the power law dependence extracted from our data.

In summary, we have made the first measurement of exclusive J

/

ψ

photoproduction off protons in p–Pb

collisions at the LHC. Our data are compatible with a power law dependence of

σ

(W

γp

) up to about 700

GeV in W

_γp

, corresponding to x

∼ 2 × 10

−5

. A natural explanation is that no change in the behaviour of

the gluon PDF in the proton is observed between HERA and LHC energies.

Acknowledgements

The ALICE Collaboration would like to thank all its engineers and technicians for their invaluable

con-tributions 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

cen-tres 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:

State Committee of Science, World Federation of Scientists (WFS) and Swiss Fonds Kidagan, Armenia,

Conselho Nacional de Desenvolvimento Cient´ıfico e Tecnol´ogico (CNPq), Financiadora de Estudos e

Projetos (FINEP), Fundac¸˜ao de Amparo `a Pesquisa do Estado de S˜ao Paulo (FAPESP);

(GeV)

p γ

W

10

10

2

10

3

+p) (nb)

ψ

J/

→

+p

γ

(

σ

10

2

10

3

10

Power law fit to ALICE data

LHCb pp data (W+ solutions)

LHCb pp data (W- solutions)

Fig. 4: The power law fit to ALICE data is compared to LHCb solutions.

the Ministry of Science and Technology of China (MSTC);

Ministry of Education and Youth of the Czech Republic;

Danish Natural Science Research Council, the Carlsberg Foundation and the Danish National Research

Foundation;

The European Research Council under the European Community’s Seventh Framework Programme;

Helsinki Institute of Physics and the Academy of Finland;

French CNRS-IN2P3, the ‘Region Pays de Loire’, ‘Region Alsace’, ‘Region Auvergne’ and CEA,

France;

German BMBF and the Helmholtz Association;

General Secretariat for Research and Technology, Ministry of Development, Greece;

Hungarian OTKA and National Office for Research and Technology (NKTH);

Department of Atomic Energy and Department of Science and Technology of the Government of India;

Istituto Nazionale di Fisica Nucleare (INFN) and Centro Fermi - Museo Storico della Fisica e Centro

Studi e Ricerche “Enrico Fermi”, Italy;

MEXT Grant-in-Aid for Specially Promoted Research, Japan;

Joint Institute for Nuclear Research, Dubna;

National Research Foundation of Korea (NRF);

CONACYT, DGAPA, M´exico, ALFA-EC and the EPLANET Program (European Particle Physics Latin

American Network)

Stichting voor Fundamenteel Onderzoek der Materie (FOM) and the Nederlandse Organisatie voor

Wetenschappelijk Onderzoek (NWO), Netherlands;

Research Council of Norway (NFR);

Polish Ministry of Science and Higher Education;

National Science Centre, Poland;

Ministry of Education and Science of Russian Federation, Russian Academy of Sciences, Russian

Fed-eral Agency of Atomic Energy, Russian FedFed-eral Agency for Science and Innovations and The Russian

Foundation for Basic Research;

Ministry of Education of Slovakia;

Department of Science and Technology, South Africa;

CIEMAT, EELA, Ministerio de Econom´ıa y Competitividad (MINECO) of Spain, Xunta de Galicia

(Conseller´ıa de Educaci´on), CEADEN, Cubaenerg´ıa, Cuba, and IAEA (International Atomic Energy

Agency);

Swedish Research Council (VR) and Knut & Alice Wallenberg Foundation (KAW);

Ukraine Ministry of Education and Science;

United Kingdom Science and Technology Facilities Council (STFC);

The United States Department of Energy, the United States National Science Foundation, the State of

Texas, and the State of Ohio;

Ministry of Science, Education and Sports of Croatia and Unity through Knowledge Fund, Croatia.

References

[1] M. G. Ryskin, “Diffractive J / psi electroproduction in LLA QCD,” Z. Phys. C 57, 89 (1993).

[2] N. Armesto and A. H. Rezaeian, “Exclusive vector meson production at high energies and gluon

saturation,” arXiv:1402.4831 [hep-ph].

[3] L. V. Gribov, E. M. Levin and M. G. Ryskin, “Semihard Processes in QCD,” Phys. Rept. 100, 1

(1983).

[4] A. H. Mueller, “Small x Behavior and Parton Saturation: A QCD Model,” Nucl. Phys. B 335, 115

(1990).

[5] J. L. Abelleira Fernandez, et al., “A Large Hadron Electron Collider at CERN,” arXiv:1211.4831

[hep-ex].

[6] A. Accardi, et al., “Electron Ion Collider: The Next QCD Frontier - Understanding the glue that

binds us all,” arXiv:1212.1701 [nucl-ex].

[7] S. Chekanov et al. [ZEUS Collaboration], “Exclusive photoproduction of J / psi mesons at HERA,”

Eur. Phys. J. C 24, 345 (2002).

[8] A. Aktas et al. [H1 Collaboration], “Elastic J/psi production at HERA,” Eur. Phys. J. C 46, 585

(2006).

[9] C. Alexa et al. [H1 Collaboration], “Elastic and Proton-Dissociative Photoproduction of J/psi

Mesons at HERA,” Eur. Phys. J. C 73, 2466 (2013).

[10] R. Aaij et al. [LHCb Collaboration], “Updated measurements of exclusive J/ and (2S) production

cross-sections in pp collisions at

√

s = 7 TeV,” J. Phys. G 41, 055002 (2014).

[11] T. Aaltonen et al. [CDF Collaboration], “Observation of exclusive charmonium production and

gamma gamma —¿ mu+mu- in p anti-p collisions at s**(1/2) = 1.96-TeV,” Phys. Rev. Lett. 102,

242001 (2009).

[12] B. Abelev et al. [ALICE Collaboration], “Coherent J

/

ψ

photoproduction in ultra-peripheral Pb-Pb

collisions at

√

s

NN

= 2.76 TeV,” Phys. Lett. B 718, 1273 (2013).

[13] E. Abbas et al. [ALICE Collaboration], “Charmonium and e

+

e

−

pair photoproduction at

mid-rapidity in ultra-peripheral Pb-Pb collisions at

√

s

NN

= 2.76 TeV,” Eur. Phys. J. C 73, 2617 (2013).

[14] S. Afanasiev et al. [PHENIX Collaboration], “Photoproduction of J/psi and of high mass e+e- in

ultra-peripheral Au+Au collisions at s**(1/2) = 200-GeV,” Phys. Lett. B 679, 321 (2009).

[15] L. Frankfurt, M. Strikman and M. Zhalov, “Elastic and large t rapidity gap vector meson production

in ultraperipheral proton-ion collisions,” Phys. Lett. B 640, 162 (2006).

[16] V. Guzey and M. Zhalov, “Rapidity and momentum transfer distributions of coherent J

/

ψ

photo-production in ultraperipheral pPb collisions at the LHC,” JHEP 1402, 046 (2014).

[17] K. Aamodt et al. [ALICE Collaboration], “The ALICE experiment at the CERN LHC,” JINST 3,

S08002 (2008).

[18] B. B. Abelev et al. [ALICE Collaboration], “Measurement of visible cross sections in proton-lead

collisions at

√

s

NN

= 5.02 TeV in van der Meer scans with the ALICE detector,” arXiv:1405.1849

[nucl-ex].

[19] B. B. Abelev et al. [ALICE Collaboration], “J

/

ψ

production and nuclear effects in p-Pb collisions

at

√

S

NN

= 5.02 TeV,” JHEP 1402, 073 (2014).

[20] J. Gaiser, “Charmonium Spectroscopy From Radiative Decays of the J

/

ψ

and

ψ

′

,” SLAC Stanford

- SLAC-255 (82,REC.JUN.83) 194p

[21] S. Klein and J. Nystrand, “Exclusive vector meson production in relativistic heavy ion collisions,”

Phys. Rev. C 60, 014903 (1999).

[22] STARLIGHT website, http://starlight.hepforge.org/.

[23] A. J. Schramm and D. H. Reeves, “Production of eta mesons in double pomeron exchange,” Phys.

Rev. D 55, 7312 (1997).

[24] L. A. Harland-Lang, V. A. Khoze, M. G. Ryskin and W. J. Stirling, “Standard candle central

exclu-sive processes at the Tevatron and LHC,” Eur. Phys. J. C 69, 179 (2010).

[25] J. Beringer et al. [Particle Data Group Collaboration], “Review of Particle Physics (RPP),” Phys.

Rev. D 86, 010001 (2012).

[26] F. D. Aaron et al. [H1 and ZEUS Collaboration], “Combined Measurement and QCD Analysis of

the Inclusive e+- p Scattering Cross Sections at HERA,” JHEP 1001, 109 (2010).

[27] S. P. Jones, A. D. Martin, M. G. Ryskin and T. Teubner, “Probes of the small x gluon via exclusive

J

/

ψ

and

ϒ

production at HERA and the LHC,” JHEP 1311, 085 (2013).

[28] H. Kowalski, L. Motyka and G. Watt, “Exclusive diffractive processes at HERA within the dipole

picture,” Phys. Rev. D 74, 074016 (2006).

[29] F. Gelis, E. Iancu, J. Jalilian-Marian and R. Venugopalan, “The Color Glass Condensate,” Ann.

Rev. Nucl. Part. Sci. 60, 463 (2010).

A

The ALICE Collaboration

B. Abelev71, J. Adam37, D. Adamov´a79, M.M. Aggarwal83, G. Aglieri Rinella34, M. Agnello107 ,90, A. Agostinelli26_{, N. Agrawal}44_{, Z. Ahammed}126_{, N. Ahmad}18_{, I. Ahmed}15_{, S.U. Ahn}64_{, S.A. Ahn}64_,

I. Aimo107 ,90_{, S. Aiola}131_{, M. Ajaz}15_{, A. Akindinov}54_{, S.N. Alam}126_{, D. Aleksandrov}96_{, B. Alessandro}107_,

D. Alexandre98, A. Alici12 ,101, A. Alkin3, J. Alme35, T. Alt39, S. Altinpinar17, I. Altsybeev125, C. Alves Garcia Prado115, C. Andrei74, A. Andronic93, V. Anguelov89, J. Anielski50, T. Antiˇci´c94, F. Antinori104, P. Antonioli101, L. Aphecetche109, H. Appelsh¨auser49, S. Arcelli26, N. Armesto16, R. Arnaldi107, T. Aronsson131, I.C. Arsene93 ,21, M. Arslandok49, A. Augustinus34, R. Averbeck93, T.C. Awes80, M.D. Azmi18 ,85, M. Bach39, A. Badal`a103, Y.W. Baek40 ,66, S. Bagnasco107, R. Bailhache49, R. Bala86, A. Baldisseri14, F. Baltasar Dos Santos Pedrosa34, R.C. Baral57, R. Barbera27, F. Barile31, G.G. Barnaf¨oldi130, L.S. Barnby98, V. Barret66, J. Bartke112, M. Basile26, N. Bastid66, S. Basu126, B. Bathen50, G. Batigne109, A. Batista Camejo66, B. Batyunya62, P.C. Batzing21, C. Baumann49, I.G. Bearden76, H. Beck49, C. Bedda90, N.K. Behera44, I. Belikov51, F. Bellini26, R. Bellwied117, E. Belmont-Moreno60, R. Belmont III129, V. Belyaev72, G. Bencedi130, S. Beole25, I. Berceanu74, A. Bercuci74, Y. Berdnikov,ii,81, D. Berenyi130, M.E. Berger88, R.A. Bertens53, D. Berzano25, L. Betev34, A. Bhasin86, I.R. Bhat86, A.K. Bhati83, B. Bhattacharjee41, J. Bhom122, L. Bianchi25, N. Bianchi68, C. Bianchin53, J. Bielˇc´ık37, J. Bielˇc´ıkov´a79, A. Bilandzic76, S. Bjelogrlic53, F. Blanco10, D. Blau96,

C. Blume49, F. Bock70 ,89, A. Bogdanov72, H. Bøggild76, M. Bogolyubsky108, F.V. B¨ohmer88, L. Boldizs´ar130, M. Bombara38_{, J. Book}49_{, H. Borel}14_{, A. Borissov}129 ,92_{, F. Boss´u}61_{, M. Botje}77_{, E. Botta}25_{, S. B¨ottger}48_,

P. Braun-Munzinger93_{, M. Bregant}115_{, T. Breitner}48_{, T.A. Broker}49_{, T.A. Browning}91_{, M. Broz}37_{, E. Bruna}107_,

G.E. Bruno31, D. Budnikov95, H. Buesching49, S. Bufalino107, P. Buncic34, O. Busch89, Z. Buthelezi61, D. Caffarri34 ,28, X. Cai7, H. Caines131, L. Calero Diaz68, A. Caliva53, E. Calvo Villar99, P. Camerini24, F. Carena34, W. Carena34, J. Castillo Castellanos14, E.A.R. Casula23, V. Catanescu74, C. Cavicchioli34, C. Ceballos Sanchez9, J. Cepila37, P. Cerello107, B. Chang118, S. Chapeland34, J.L. Charvet14,

S. Chattopadhyay126, S. Chattopadhyay97, V. Chelnokov3, M. Cherney82, C. Cheshkov124, B. Cheynis124, V. Chibante Barroso34, D.D. Chinellato116 ,117, P. Chochula34, M. Chojnacki76, S. Choudhury126,

P. Christakoglou77, C.H. Christensen76, P. Christiansen32, T. Chujo122, S.U. Chung92, C. Cicalo102, L. Cifarelli26 ,12, F. Cindolo101, J. Cleymans85, F. Colamaria31, D. Colella31, A. Collu23, M. Colocci26, G. Conesa Balbastre67, Z. Conesa del Valle47, M.E. Connors131, J.G. Contreras11 ,37, T.M. Cormier80 ,129, Y. Corrales Morales25, P. Cortese30, I. Cort´es Maldonado2, M.R. Cosentino115, F. Costa34, P. Crochet66, R. Cruz Albino11, E. Cuautle59, L. Cunqueiro68 ,34, A. Dainese104, R. Dang7, A. Danu58, D. Das97, I. Das47, K. Das97_{, S. Das}4_{, A. Dash}116_{, S. Dash}44_{, S. De}126_{, H. Delagrange}109 ,i_{, A. Deloff}73_{, E. D´enes}130_,

G. D’Erasmo31_{, A. De Caro}29 ,12_{, G. de Cataldo}100_{, J. de Cuveland}39_{, A. De Falco}23_{, D. De Gruttola}29 ,12_,

N. De Marco107_{, S. De Pasquale}29_{, R. de Rooij}53_{, M.A. Diaz Corchero}10_{, T. Dietel}50 ,85_{, P. Dillenseger}49_,

R. Divi`a34, D. Di Bari31, S. Di Liberto105, A. Di Mauro34, P. Di Nezza68, Ø. Djuvsland17, A. Dobrin53, T. Dobrowolski73, D. Domenicis Gimenez115, B. D¨onigus49, O. Dordic21, S. Dørheim88, A.K. Dubey126, A. Dubla53, L. Ducroux124, P. Dupieux66, A.K. Dutta Majumdar97, T. E. Hilden42, R.J. Ehlers131, D. Elia100, H. Engel48, B. Erazmus34 ,109, H.A. Erdal35, D. Eschweiler39, B. Espagnon47, M. Esposito34, M. Estienne109, S. Esumi122, D. Evans98, S. Evdokimov108, D. Fabris104, J. Faivre67, D. Falchieri26, A. Fantoni68,

M. Fasel89 ,70, D. Fehlker17, L. Feldkamp50, D. Felea58, A. Feliciello107, G. Feofilov125, J. Ferencei79, A. Fern´andez T´ellez2, E.G. Ferreiro16, A. Ferretti25, A. Festanti28, J. Figiel112, M.A.S. Figueredo119, S. Filchagin95, D. Finogeev52, F.M. Fionda31, E.M. Fiore31, E. Floratos84, M. Floris34, S. Foertsch61, P. Foka93, S. Fokin96, E. Fragiacomo106, A. Francescon34 ,28, U. Frankenfeld93, U. Fuchs34, C. Furget67, A. Furs52, M. Fusco Girard29, J.J. Gaardhøje76, M. Gagliardi25, A.M. Gago99, M. Gallio25,

D.R. Gangadharan19 ,70, P. Ganoti80 ,84, C. Gao7, C. Garabatos93, E. Garcia-Solis13, C. Gargiulo34, I. Garishvili71, J. Gerhard39, M. Germain109, A. Gheata34, M. Gheata34 ,58, B. Ghidini31, P. Ghosh126, S.K. Ghosh4, P. Gianotti68, P. Giubellino34, E. Gladysz-Dziadus112, P. Gl¨assel89, A. Gomez Ramirez48, P. Gonz´alez-Zamora10_{, S. Gorbunov}39_{, L. G¨orlich}112_{, S. Gotovac}111_{, L.K. Graczykowski}128_{, A. Grelli}53_,

A. Grigoras34_{, C. Grigoras}34_{, V. Grigoriev}72_{, A. Grigoryan}1_{, S. Grigoryan}62_{, B. Grinyov}3_{, N. Grion}106_,

J.F. Grosse-Oetringhaus34_{, J.-Y. Grossiord}124_{, R. Grosso}34_{, F. Guber}52_{, R. Guernane}67_{, B. Guerzoni}26_,

M. Guilbaud124, K. Gulbrandsen76, H. Gulkanyan1, M. Gumbo85, T. Gunji121, A. Gupta86, R. Gupta86, K. H. Khan15, R. Haake50, Ø. Haaland17, C. Hadjidakis47, M. Haiduc58, H. Hamagaki121, G. Hamar130, L.D. Hanratty98, A. Hansen76, J.W. Harris131, H. Hartmann39, A. Harton13, D. Hatzifotiadou101,

S. Hayashi121, S.T. Heckel49, M. Heide50, H. Helstrup35, A. Herghelegiu74, G. Herrera Corral11, B.A. Hess33, K.F. Hetland35, B. Hippolyte51, J. Hladky56, P. Hristov34, M. Huang17, T.J. Humanic19, N. Hussain41, D. Hutter39, D.S. Hwang20, R. Ilkaev95, I. Ilkiv73, M. Inaba122, G.M. Innocenti25, C. Ionita34, M. Ippolitov96,

M. Irfan18, M. Ivanov93, V. Ivanov81, A. Jachołkowski27, P.M. Jacobs70, C. Jahnke115, H.J. Jang64, M.A. Janik128, P.H.S.Y. Jayarathna117, C. Jena28, S. Jena117, R.T. Jimenez Bustamante59, P.G. Jones98,

H. Jung40, A. Jusko98, V. Kadyshevskiy62, S. Kalcher39, P. Kalinak55, A. Kalweit34, J. Kamin49, J.H. Kang132, V. Kaplin72, S. Kar126, A. Karasu Uysal65, O. Karavichev52, T. Karavicheva52, E. Karpechev52,

U. Kebschull48, R. Keidel133, D.L.D. Keijdener53, M. Keil SVN34, M.M. Khan,iii,18, P. Khan97, S.A. Khan126, A. Khanzadeev81, Y. Kharlov108, B. Kileng35, B. Kim132, D.W. Kim64 ,40, D.J. Kim118, J.S. Kim40, M. Kim40, M. Kim132, S. Kim20, T. Kim132, S. Kirsch39, I. Kisel39, S. Kiselev54, A. Kisiel128, G. Kiss130, J.L. Klay6, J. Klein89, C. Klein-B¨osing50, A. Kluge34, M.L. Knichel93, A.G. Knospe113, C. Kobdaj110 ,34, M. Kofarago34, M.K. K¨ohler93, T. Kollegger39, A. Kolojvari125, V. Kondratiev125, N. Kondratyeva72, A. Konevskikh52, V. Kovalenko125, M. Kowalski112, S. Kox67, G. Koyithatta Meethaleveedu44, J. Kral118, I. Kr´alik55,

A. Kravˇc´akov´a38, M. Krelina37, M. Kretz39, M. Krivda98 ,55, F. Krizek79, E. Kryshen34, M. Krzewicki93 ,39, V. Kuˇcera79_{, Y. Kucheriaev}96 ,i_{, T. Kugathasan}34_{, C. Kuhn}51_{, P.G. Kuijer}77_{, I. Kulakov}49_{, J. Kumar}44_,

P. Kurashvili73_{, A. Kurepin}52_{, A.B. Kurepin}52_{, A. Kuryakin}95_{, S. Kushpil}79_{, M.J. Kweon}46 ,89_{, Y. Kwon}132_,

P. Ladron de Guevara59_{, C. Lagana Fernandes}115_{, I. Lakomov}47_{, R. Langoy}127_{, C. Lara}48_{, A. Lardeux}109_,

A. Lattuca25_{, S.L. La Pointe}53 ,107_{, P. La Rocca}27_{, R. Lea}24_{, L. Leardini}89_{, G.R. Lee}98_{, I. Legrand}34_,

J. Lehnert49_{, R.C. Lemmon}78_{, V. Lenti}100_{, E. Leogrande}53_{, M. Leoncino}25_{, I. Le´on Monz´on}114_{, P. L´evai}130_,

S. Li7 ,66, J. Lien127, R. Lietava98, S. Lindal21, V. Lindenstruth39, C. Lippmann93, M.A. Lisa19,

H.M. Ljunggren32, D.F. Lodato53, P.I. Loenne17, V.R. Loggins129, V. Loginov72, D. Lohner89, C. Loizides70, X. Lopez66, E. L´opez Torres9, X.-G. Lu89, P. Luettig49, M. Lunardon28, G. Luparello53 ,24, R. Ma131, A. Maevskaya52, M. Mager34, D.P. Mahapatra57, S.M. Mahmood21, A. Maire51 ,89, R.D. Majka131,

M. Malaev81, I. Maldonado Cervantes59, L. Malinina,iv,62, D. Mal’Kevich54, P. Malzacher93, A. Mamonov95, L. Manceau107, V. Manko96, F. Manso66, V. Manzari100, M. Marchisone66 ,25, J. Mareˇs56, G.V. Margagliotti24, A. Margotti101, A. Mar´ın93, C. Markert113, M. Marquard49, I. Martashvili120, N.A. Martin93, P. Martinengo34, M.I. Mart´ınez2, G. Mart´ınez Garc´ıa109, J. Martin Blanco109, Y. Martynov3, A. Mas109, S. Masciocchi93, M. Masera25, A. Masoni102, L. Massacrier109, A. Mastroserio31, A. Matyja112, C. Mayer112, J. Mazer120, M.A. Mazzoni105, F. Meddi22, A. Menchaca-Rocha60, E. Meninno29, J. Mercado P´erez89, M. Meres36, Y. Miake122, K. Mikhaylov54 ,62, L. Milano34, J. Milosevic,v,21, A. Mischke53, A.N. Mishra45,

D. Mi´skowiec93_{, J. Mitra}126_{, C.M. Mitu}58_{, J. Mlynarz}129_{, N. Mohammadi}53_{, B. Mohanty}75 ,126_{, L. Molnar}51_,

L. Monta˜no Zetina11_{, E. Montes}10_{, M. Morando}28_{, D.A. Moreira De Godoy}115 ,109_{, S. Moretto}28_,

A. Morreale109, A. Morsch34, V. Muccifora68, E. Mudnic111, D. M¨uhlheim50, S. Muhuri126, M. Mukherjee126, H. M¨uller34, M.G. Munhoz115, S. Murray85, L. Musa34, J. Musinsky55, B.K. Nandi44, R. Nania101,

E. Nappi100, C. Nattrass120, K. Nayak75, T.K. Nayak126, S. Nazarenko95, A. Nedosekin54, M. Nicassio93, M. Niculescu34 ,58, B.S. Nielsen76, S. Nikolaev96, S. Nikulin96, V. Nikulin81, B.S. Nilsen82, F. Noferini12 ,101, P. Nomokonov62, G. Nooren53, J. Norman119, A. Nyanin96, J. Nystrand17, H. Oeschler89, S. Oh131,

S.K. Oh,vi,63 ,40, A. Okatan65, L. Olah130, J. Oleniacz128, A.C. Oliveira Da Silva115, J. Onderwaater93,

C. Oppedisano107, A. Ortiz Velasquez59 ,32, A. Oskarsson32, J. Otwinowski112 ,93, K. Oyama89, M. Ozdemir49, P. Sahoo45, Y. Pachmayer89, M. Pachr37, P. Pagano29, G. Pai´c59, F. Painke39, C. Pajares16, S.K. Pal126, A. Palmeri103, D. Pant44, V. Papikyan1, G.S. Pappalardo103, P. Pareek45, W.J. Park93, S. Parmar83, A. Passfeld50, D.I. Patalakha108, V. Paticchio100, B. Paul97, T. Pawlak128, T. Peitzmann53,

H. Pereira Da Costa14, E. Pereira De Oliveira Filho115, D. Peresunko96, C.E. P´erez Lara77, A. Pesci101, V. Peskov49_{, Y. Pestov}5_{, V. Petr´aˇcek}37_{, M. Petran}37_{, M. Petris}74_{, M. Petrovici}74_{, C. Petta}27_{, S. Piano}106_,

M. Pikna36_{, P. Pillot}109_{, O. Pinazza}101 ,34_{, L. Pinsky}117_{, D.B. Piyarathna}117_{, M. Płosko ´n}70_{, M. Planinic}123 ,94_,

J. Pluta128_{, S. Pochybova}130_{, P.L.M. Podesta-Lerma}114_{, M.G. Poghosyan}82 ,34_{, E.H.O. Pohjoisaho}42_,

B. Polichtchouk108_{, N. Poljak}94 ,123_{, A. Pop}74_{, S. Porteboeuf-Houssais}66_{, J. Porter}70_{, B. Potukuchi}86_,

S.K. Prasad129 ,4_{, R. Preghenella}101 ,12_{, F. Prino}107_{, C.A. Pruneau}129_{, I. Pshenichnov}52_{, G. Puddu}23_,

P. Pujahari129, V. Punin95, J. Putschke129, H. Qvigstad21, A. Rachevski106, S. Raha4, J. Rak118, A. Rakotozafindrabe14, L. Ramello30, R. Raniwala87, S. Raniwala87, S.S. R¨as¨anen42, B.T. Rascanu49, D. Rathee83, A.W. Rauf15, V. Razazi23, K.F. Read120, J.S. Real67, K. Redlich,vii,73, R.J. Reed129 ,131, A. Rehman17, P. Reichelt49, M. Reicher53, F. Reidt89 ,34, R. Renfordt49, A.R. Reolon68, A. Reshetin52, F. Rettig39, J.-P. Revol34, K. Reygers89, V. Riabov81, R.A. Ricci69, T. Richert32, M. Richter21, P. Riedler34, W. Riegler34, F. Riggi27, A. Rivetti107, E. Rocco53, M. Rodr´ıguez Cahuantzi2, A. Rodriguez Manso77, K. Røed21, E. Rogochaya62, S. Rohni86, D. Rohr39, D. R¨ohrich17, R. Romita78 ,119, F. Ronchetti68, L. Ronflette109, P. Rosnet66, A. Rossi34, F. Roukoutakis84, A. Roy45, C. Roy51, P. Roy97,

A.J. Rubio Montero10, R. Rui24, R. Russo25, E. Ryabinkin96, Y. Ryabov81, A. Rybicki112, S. Sadovsky108, K. ˇSafaˇr´ık34, B. Sahlmuller49, R. Sahoo45, P.K. Sahu57, J. Saini126, S. Sakai68, C.A. Salgado16,

A. Sandoval60, M. Sano122, G. Santagati27, D. Sarkar126, E. Scapparone101, F. Scarlassara28, R.P. Scharenberg91, C. Schiaua74, R. Schicker89, C. Schmidt93, H.R. Schmidt33, S. Schuchmann49, J. Schukraft34, M. Schulc37, T. Schuster131, Y. Schutz109 ,34, K. Schwarz93, K. Schweda93, G. Scioli26, E. Scomparin107, R. Scott120, G. Segato28, J.E. Seger82, Y. Sekiguchi121, I. Selyuzhenkov93, J. Seo92, E. Serradilla10 ,60, A. Sevcenco58, A. Shabetai109, G. Shabratova62, R. Shahoyan34, A. Shangaraev108, N. Sharma120, S. Sharma86, K. Shigaki43, K. Shtejer25 ,9, Y. Sibiriak96, S. Siddhanta102, T. Siemiarczuk73, D. Silvermyr80, C. Silvestre67, G. Simatovic123, R. Singaraju126, R. Singh86, S. Singha126 ,75, V. Singhal126, B.C. Sinha126, T. Sinha97, B. Sitar36, M. Sitta30, T.B. Skaali21, K. Skjerdal17, M. Slupecki118, N. Smirnov131, R.J.M. Snellings53, C. Søgaard32, R. Soltz71, J. Song92, M. Song132, F. Soramel28, S. Sorensen120,

M. Spacek37, E. Spiriti68, I. Sputowska112, M. Spyropoulou-Stassinaki84, B.K. Srivastava91, J. Stachel89, I. Stan58, G. Stefanek73, M. Steinpreis19, E. Stenlund32, G. Steyn61, J.H. Stiller89, D. Stocco109,

M. Stolpovskiy108_{, P. Strmen}36_{, A.A.P. Suaide}115_{, T. Sugitate}43_{, C. Suire}47_{, M. Suleymanov}15_{, R. Sultanov}54_,

M. ˇSumbera79_{, T. Susa}94_{, T.J.M. Symons}70_{, A. Szabo}36_{, A. Szanto de Toledo}115_{, I. Szarka}36_,

A. Szczepankiewicz34_{, M. Szymanski}128_{, J. Takahashi}116_{, M.A. Tangaro}31_{, J.D. Tapia Takaki},viii,47_,

A. Tarantola Peloni49_{, A. Tarazona Martinez}34_{, M.G. Tarzila}74_{, A. Tauro}34_{, G. Tejeda Mu ˜noz}2_{, A. Telesca}34_,

C. Terrevoli23_{, J. Th¨ader}93_{, D. Thomas}53_{, R. Tieulent}124_{, A.R. Timmins}117_{, A. Toia}49 ,104_{, V. Trubnikov}3_,

W.H. Trzaska118, T. Tsuji121, A. Tumkin95, R. Turrisi104, T.S. Tveter21, K. Ullaland17, A. Uras124, G.L. Usai23, M. Vajzer79, M. Vala55 ,62, L. Valencia Palomo66, S. Vallero25 ,89, P. Vande Vyvre34, J. Van Der Maarel53, J.W. Van Hoorne34, M. van Leeuwen53, A. Vargas2, M. Vargyas118, R. Varma44, M. Vasileiou84, A. Vasiliev96, V. Vechernin125, M. Veldhoen53, A. Velure17, M. Venaruzzo24 ,69,

E. Vercellin25, S. Vergara Lim´on2, R. Vernet8, M. Verweij129, L. Vickovic111, G. Viesti28, J. Viinikainen118, Z. Vilakazi61, O. Villalobos Baillie98, A. Vinogradov96, L. Vinogradov125, Y. Vinogradov95, T. Virgili29, Y.P. Viyogi126, A. Vodopyanov62, M.A. V¨olkl89, K. Voloshin54, S.A. Voloshin129, G. Volpe34, B. von Haller34, I. Vorobyev125, D. Vranic93 ,34, J. Vrl´akov´a38, B. Vulpescu66, A. Vyushin95, B. Wagner17, J. Wagner93, V. Wagner37, M. Wang7 ,109, Y. Wang89, D. Watanabe122, M. Weber34 ,117, J.P. Wessels50, U. Westerhoff50, J. Wiechula33, J. Wikne21, M. Wilde50, G. Wilk73, J. Wilkinson89, M.C.S. Williams101, B. Windelband89, M. Winn89, C.G. Yaldo129, Y. Yamaguchi121, H. Yang53, P. Yang7, S. Yang17, S. Yano43, S. Yasnopolskiy96, J. Yi92_{, Z. Yin}7_{, I.-K. Yoo}92_{, I. Yushmanov}96_{, V. Zaccolo}76_{, C. Zach}37_{, A. Zaman}15_{, C. Zampolli}101_,

S. Zaporozhets62_{, A. Zarochentsev}125_{, P. Z´avada}56_{, N. Zaviyalov}95_{, H. Zbroszczyk}128_{, I.S. Zgura}58_,

M. Zhalov81, H. Zhang7, X. Zhang7 ,70, Y. Zhang7, C. Zhao21, N. Zhigareva54, D. Zhou7, F. Zhou7, Y. Zhou53, Zhou, Zhuo17, H. Zhu7, J. Zhu7, X. Zhu7, A. Zichichi12 ,26, A. Zimmermann89,

M.B. Zimmermann50 ,34, G. Zinovjev3, Y. Zoccarato124, M. Zyzak49

Affiliation notes

i_Deceased

ii_{Also at: St. Petersburg State Polytechnical University}

iii_{Also at: Department of Applied Physics, Aligarh Muslim University, Aligarh, India}

iv_{Also at: M.V. Lomonosov Moscow State University, D.V. Skobeltsyn Institute of Nuclear Physics,}

Moscow, Russia

v_{Also at: University of Belgrade, Faculty of Physics and ”Vinˇca” Institute of Nuclear Sciences, Belgrade,}

Serbia

vi_{Permanent Address: Permanent Address: Konkuk University, Seoul, Korea} vii_{Also at: Institute of Theoretical Physics, University of Wroclaw, Wroclaw, Poland} viii_{Also at: University of Kansas, Lawrence, KS, United States}

Collaboration Institutes

1 _{A.I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Foundation, Yerevan, Armenia} 2 _{Benem´erita Universidad Aut´onoma de Puebla, Puebla, Mexico}

3 _{Bogolyubov Institute for Theoretical Physics, Kiev, Ukraine}

4 _{Bose Institute, Department of Physics and Centre for Astroparticle Physics and Space Science (CAPSS),}

Kolkata, India

5 _{Budker Institute for Nuclear Physics, Novosibirsk, Russia}

6 _{California Polytechnic State University, San Luis Obispo, CA, United States} 7 _{Central China Normal University, Wuhan, China}

9 _{Centro de Aplicaciones Tecnol´ogicas y Desarrollo Nuclear (CEADEN), Havana, Cuba}

10 _{Centro de Investigaciones Energ´eticas Medioambientales y Tecnol´ogicas (CIEMAT), Madrid, Spain} 11 _{Centro de Investigaci´on y de Estudios Avanzados (CINVESTAV), Mexico City and M´erida, Mexico} 12 _{Centro Fermi - Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Rome, Italy} 13 _{Chicago State University, Chicago, USA}

14 _{Commissariat `a l’Energie Atomique, IRFU, Saclay, France}

15 _{COMSATS Institute of Information Technology (CIIT), Islamabad, Pakistan}

16 _{Departamento de F´ısica de Part´ıculas and IGFAE, Universidad de Santiago de Compostela, Santiago de}

Compostela, Spain

17 _{Department of Physics and Technology, University of Bergen, Bergen, Norway} 18 _{Department of Physics, Aligarh Muslim University, Aligarh, India}

19 _{Department of Physics, Ohio State University, Columbus, OH, United States} 20 _{Department of Physics, Sejong University, Seoul, South Korea}

21 _{Department of Physics, University of Oslo, Oslo, Norway}

22 _{Dipartimento di Fisica dell’Universit`a ’La Sapienza’ and Sezione INFN Rome, Italy</sub> 23 <sub>Dipartimento di Fisica dell’Universit`a and Sezione INFN, Cagliari, Italy}

24 _{Dipartimento di Fisica dell’Universit`a and Sezione INFN, Trieste, Italy</sub> 25 <sub>Dipartimento di Fisica dell’Universit`a and Sezione INFN, Turin, Italy}

26 _{Dipartimento di Fisica e Astronomia dell’Universit`a and Sezione INFN, Bologna, Italy</sub> 27 <sub>Dipartimento di Fisica e Astronomia dell’Universit`a and Sezione INFN, Catania, Italy} 28 _{Dipartimento di Fisica e Astronomia dell’Universit`a and Sezione INFN, Padova, Italy}

29 _{Dipartimento di Fisica ‘E.R. Caianiello’ dell’Universit`a and Gruppo Collegato INFN, Salerno, Italy</sub> 30 <sub>Dipartimento di Scienze e Innovazione Tecnologica dell’Universit`a del Piemonte Orientale and Gruppo}

Collegato INFN, Alessandria, Italy

31 _{Dipartimento Interateneo di Fisica ‘M. Merlin’ and Sezione INFN, Bari, Italy} 32 _{Division of Experimental High Energy Physics, University of Lund, Lund, Sweden} 33 _{Eberhard Karls Universit¨at T¨ubingen, T¨ubingen, Germany}

34 _{European Organization for Nuclear Research (CERN), Geneva, Switzerland} 35 _{Faculty of Engineering, Bergen University College, Bergen, Norway}

36 _{Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovakia}

37 _{Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague,}

Czech Republic

38 _{Faculty of Science, P.J. ˇSaf´arik University, Koˇsice, Slovakia}

39 _{Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe-Universit¨at Frankfurt, Frankfurt,}

Germany

40 _{Gangneung-Wonju National University, Gangneung, South Korea} 41 _{Gauhati University, Department of Physics, Guwahati, India} 42 _{Helsinki Institute of Physics (HIP), Helsinki, Finland} 43 _{Hiroshima University, Hiroshima, Japan}

44 _{Indian Institute of Technology Bombay (IIT), Mumbai, India} 45 _{Indian Institute of Technology Indore, Indore (IITI), India} 46 _{Inha University, Incheon, South Korea}

47 _{Institut de Physique Nucl´eaire d’Orsay (IPNO), Universit´e Paris-Sud, CNRS-IN2P3, Orsay, France} 48 _{Institut f¨ur Informatik, Johann Wolfgang Goethe-Universit¨at Frankfurt, Frankfurt, Germany} 49 _{Institut f¨ur Kernphysik, Johann Wolfgang Goethe-Universit¨at Frankfurt, Frankfurt, Germany} 50 _{Institut f¨ur Kernphysik, Westf¨alische Wilhelms-Universit¨at M¨unster, M¨unster, Germany}

51 _{Institut Pluridisciplinaire Hubert Curien (IPHC), Universit´e de Strasbourg, CNRS-IN2P3, Strasbourg,}

France

52 _{Institute for Nuclear Research, Academy of Sciences, Moscow, Russia} 53 _{Institute for Subatomic Physics of Utrecht University, Utrecht, Netherlands} 54 _{Institute for Theoretical and Experimental Physics, Moscow, Russia}

55 _{Institute of Experimental Physics, Slovak Academy of Sciences, Koˇsice, Slovakia}

56 _{Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic} 57 _{Institute of Physics, Bhubaneswar, India}

58 _{Institute of Space Science (ISS), Bucharest, Romania}

60 _{Instituto de F´ısica, Universidad Nacional Aut´onoma de M´exico, Mexico City, Mexico} 61 _{iThemba LABS, National Research Foundation, Somerset West, South Africa} 62 _{Joint Institute for Nuclear Research (JINR), Dubna, Russia}

63 _{Konkuk University, Seoul, South Korea}

64 _{Korea Institute of Science and Technology Information, Daejeon, South Korea} 65 _{KTO Karatay University, Konya, Turkey}

66 _{Laboratoire de Physique Corpusculaire (LPC), Clermont Universit´e, Universit´e Blaise Pascal,}

CNRS–IN2P3, Clermont-Ferrand, France

67 _{Laboratoire de Physique Subatomique et de Cosmologie, Universit´e Grenoble-Alpes, CNRS-IN2P3,}

Grenoble, France

68 _{Laboratori Nazionali di Frascati, INFN, Frascati, Italy} 69 _{Laboratori Nazionali di Legnaro, INFN, Legnaro, Italy}

70 _{Lawrence Berkeley National Laboratory, Berkeley, CA, United States} 71 _{Lawrence Livermore National Laboratory, Livermore, CA, United States} 72 _{Moscow Engineering Physics Institute, Moscow, Russia}

73 _{National Centre for Nuclear Studies, Warsaw, Poland}

74 _{National Institute for Physics and Nuclear Engineering, Bucharest, Romania} 75 _{National Institute of Science Education and Research, Bhubaneswar, India} 76 _{Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark} 77 _{Nikhef, National Institute for Subatomic Physics, Amsterdam, Netherlands} 78 _{Nuclear Physics Group, STFC Daresbury Laboratory, Daresbury, United Kingdom}

79 _{Nuclear Physics Institute, Academy of Sciences of the Czech Republic, ˇReˇz u Prahy, Czech Republic} 80 _{Oak Ridge National Laboratory, Oak Ridge, TN, United States}

81 _{Petersburg Nuclear Physics Institute, Gatchina, Russia}

82 _{Physics Department, Creighton University, Omaha, NE, United States} 83 _{Physics Department, Panjab University, Chandigarh, India}

84 _{Physics Department, University of Athens, Athens, Greece}

85 _{Physics Department, University of Cape Town, Cape Town, South Africa} 86 _{Physics Department, University of Jammu, Jammu, India}

87 _{Physics Department, University of Rajasthan, Jaipur, India}

88 _{Physik Department, Technische Universit¨at M¨unchen, Munich, Germany}

89 _{Physikalisches Institut, Ruprecht-Karls-Universit¨at Heidelberg, Heidelberg, Germany} 90 _{Politecnico di Torino, Turin, Italy}

91 _{Purdue University, West Lafayette, IN, United States} 92 _{Pusan National University, Pusan, South Korea}

93 _{Research Division and ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum f¨ur}

Schwerionenforschung, Darmstadt, Germany

94 _{Rudjer Boˇskovi´c Institute, Zagreb, Croatia}

95 _{Russian Federal Nuclear Center (VNIIEF), Sarov, Russia} 96 _{Russian Research Centre Kurchatov Institute, Moscow, Russia} 97 _{Saha Institute of Nuclear Physics, Kolkata, India}

98 _{School of Physics and Astronomy, University of Birmingham, Birmingham, United Kingdom} 99 _{Secci´on F´ısica, Departamento de Ciencias, Pontificia Universidad Cat´olica del Per´u, Lima, Peru} 100 _{Sezione INFN, Bari, Italy}

101 _{Sezione INFN, Bologna, Italy} 102 _{Sezione INFN, Cagliari, Italy} 103 _{Sezione INFN, Catania, Italy} 104 _{Sezione INFN, Padova, Italy} 105 _{Sezione INFN, Rome, Italy} 106 _{Sezione INFN, Trieste, Italy} 107 _{Sezione INFN, Turin, Italy}

108 _{SSC IHEP of NRC Kurchatov institute, Protvino, Russia}

109 _{SUBATECH, Ecole des Mines de Nantes, Universit´e de Nantes, CNRS-IN2P3, Nantes, France} 110 _{Suranaree University of Technology, Nakhon Ratchasima, Thailand}

111 _{Technical University of Split FESB, Split, Croatia}

113 _{The University of Texas at Austin, Physics Department, Austin, TX, USA} 114 _{Universidad Aut´onoma de Sinaloa, Culiac´an, Mexico}

115 _{Universidade de S˜ao Paulo (USP), S˜ao Paulo, Brazil}

116 _{Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil} 117 _{University of Houston, Houston, TX, United States}

118 _{University of Jyv¨askyl¨a, Jyv¨askyl¨a, Finland}

119 _{University of Liverpool, Liverpool, United Kingdom} 120 _{University of Tennessee, Knoxville, TN, United States} 121 _{University of Tokyo, Tokyo, Japan}

122 _{University of Tsukuba, Tsukuba, Japan} 123 _{University of Zagreb, Zagreb, Croatia}

124 _{Universit´e de Lyon, Universit´e Lyon 1, CNRS/IN2P3, IPN-Lyon, Villeurbanne, France} 125 _{V. Fock Institute for Physics, St. Petersburg State University, St. Petersburg, Russia} 126 _{Variable Energy Cyclotron Centre, Kolkata, India}

127 _{Vestfold University College, Tonsberg, Norway} 128 _{Warsaw University of Technology, Warsaw, Poland} 129 _{Wayne State University, Detroit, MI, United States}

130 _{Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest, Hungary} 131 _{Yale University, New Haven, CT, United States}

132 _{Yonsei University, Seoul, South Korea}

133 _{Zentrum f¨ur Technologietransfer und Telekommunikation (ZTT), Fachhochschule Worms, Worms,}