J=
c
Elliptic Flow in Pb-Pb Collisions at ffiffiffiffiffiffiffiffiffi
p
s
NN¼ 2:76 TeV
E. Abbas et al.* (ALICE Collaboration)
(Received 24 March 2013; revised manuscript received 28 July 2013; published 17 October 2013) We report on the first measurement of inclusive J=c elliptic flow v2in heavy-ion collisions at the LHC. The measurement is performed with the ALICE detector in Pb-Pb collisions atpffiffiffiffiffiffiffiffisNN¼ 2:76 TeV in the rapidity range 2:5 < y < 4:0. The dependence of the J=c v2 on the collision centrality and on the J=c transverse momentum is studied in the range 0ffiffiffiffiffiffiffiffi pT< 10 GeV=c. For semicentral Pb-Pb collisions at
sNN
p ¼ 2:76 TeV, an indication of nonzero v
2 is observed with a largest measured value of v2¼ 0:116 0:046ðstatÞ 0:029ðsystÞ for J=c in the transverse momentum range 2 pT< 4 GeV=c. The elliptic flow measurement complements the previously reported ALICE results on the inclusive J=c nuclear modification factor and favors the scenario of a significant fraction of J=c production from charm quarks in a deconfined partonic phase.
DOI:10.1103/PhysRevLett.111.162301 PACS numbers: 25.75.Cj, 25.75.Ld, 25.75.Nq
Ultrarelativistic heavy-ion collisions enable the study of matter at high temperature and pressure where quantum chromodynamics predicts the existence of a deconfined state of partonic matter, the quark-gluon plasma (QGP). Heavy quarks are expected to be produced in the primary partonic scatterings and to interact with this partonic me-dium making them ideal probes of the QGP. Quarkonia (a heavy quark and antiquark bound state) are therefore expected to be sensitive to the properties of the strongly interacting system formed in the early stages of heavy-ion collisions [1]. According to the color-screening model [2], quarkonium states are suppressed in the medium with different dissociation probabilities for the various states. Recently, the CMS Collaboration at the Large Hadron Collider (LHC) reported about the observation of the sequential suppression in the sector [3]. The ALICE Collaboration published the inclusive [4] J=c nuclear modification factor RAA down to zero transverse
momen-tum (pT) at forward rapidity in Pb-Pb collisions atpffiffiffiffiffiffiffiffisNN ¼
2:76 TeV [5]. The RAA compares the yields in Pb-Pb to
those in pp collisions scaled by the number of binary nucleon-nucleon collisions. The inclusive J=c RAA
reported is larger than that measured at the SPS [6] and at RHIC [7,8] for central collisions and does not exhibit a significant centrality dependence. Complementarily, the CMS Collaboration measured the high pT (6:5
pT< 30 GeV=c) prompt J=c RAA in the rapidity range
jyj < 2:4 [9]. The CMS data show that high pT J=c are
more suppressed than low pT J=c and that this
suppres-sion does exhibit a strong centrality dependence.
The low pT J=c RAA can be qualitatively understood
with models including full [10,11] or partial [12,13] regen-eration of J=c from deconfined charm quarks in the me-dium. This mechanism was first proposed by the statistical hadronization model, which assumes deconfinement and thermal equilibrium of the bulk of c c pairs to produce J=c at the phase boundary by statistical hadronization only [10]. Later, the transport models proposed a dynamical competition between the J=c suppression by the QGP and the regeneration mechanism, which enables them to also describe the J=c RAA versus pT [12,13]. More
dif-ferential studies, like the J=c elliptic flow, could help to assess the assumption of charm quark thermalization in the medium.
The azimuthal distribution of particles in the transverse plane is also sensitive to the dynamics of the early stages of heavy-ion collisions. In noncentral collisions, the geomet-rical overlap region and, therefore, the initial matter dis-tribution are anisotropic (almond shaped). If the matter is strongly interacting, this spatial asymmetry is converted via multiple collisions into an anisotropic momentum distribution [14]. The second coefficient of the Fourier expansion describing the final state particle azimuthal distribution with respect to the reaction plane v2 is called
elliptic flow. The reaction plane is defined by the beam axis and the impact parameter vector of the colliding nuclei.
Within the transport model scenario [12,13] observed J=c have two origins. First, primordial J=c produced in the initial hard scatterings traverse and interact with the created medium. During this process they may be dissoci-ated. Second, J=c could be regenerated from deconfined charm quarks in the QGP. Primordial J=cemitted in plane traverse a shorter path through the medium than those emitted out of plane, resulting in a small azimuthal anisot-ropy for the surviving J=c. Regenerated J=c inherit the elliptic flow of the charm quarks in the QGP. If charm quarks do thermalize in the QGP, then J=c formed there
*Full author list given at the end of the article.
Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distri-bution of this work must maintain attridistri-bution to the author(s) and the published article’s title, journal citation, and DOI.
can exhibit a large elliptic flow. In the calculation by Zhao et al. [15], the v2 of J=c at pT 2:5 GeV=c is 0.02 and
0.2 for primordial and regenerated J=c, respectively. At RHIC, the (preliminary) measurements by the (PHENIX) STAR Collaboration of the J=c v2 in Au-Au
collisions at pffiffiffiffiffiffiffiffisNN¼ 200 GeV [16,17] are consistent
with zero albeit with large uncertainties in the pT
and centrality ranges (0–5 GeV=c) 2–10 GeV=c and (20%–60%) 10%–40%. In Pb-Pb collisions at the LHC, the higher energy density of the medium should favor the charm quark thermalization, and thus increase its flow. In addition, the large number of c c pairs produced should favor the formation of J=c by regeneration mechanisms. Both effects should lead to an increase of the v2 of the
observed J=c.
In this Letter, we report ALICE results on inclusive J=c elliptic flow in Pb-Pb collisions at pffiffiffiffiffiffiffiffisNN ¼ 2:76 TeV at
forward rapidity, measured via the þ decay channel. The results are presented as a function of transverse mo-mentum and collision centrality.
The ALICE detector is described in [18]. At forward rapidity (2:5 < y < 4) the production of quarkonia is mea-sured in the muon spectrometer [19] down to pT ¼ 0. The
spectrometer consists of an absorber stopping the hadrons in front of five tracking stations comprising two planes of cathode pad chambers each, with the third station inside a dipole magnet. The tracking apparatus is completed by a triggering system made of four planes of resistive plate chambers downstream of an iron wall, which absorbs secondary hadrons escaping from the front absorber and low momentum muons. Also used in this analysis are two cylindrical layers of silicon pixel detectors, to determine the location of the interaction point, and two scintillator arrays (VZERO). The VZERO counters consist of two arrays of 32 scintillator sectors each distributed in four rings covering 2:8 5:1 (VZERO-A) and 3:7 1:7 (VZERO-C). All of these detectors have full azimuthal coverage. The data sample used for this analysis, collected in 2011, amounts to 17 106dimuon unlike sign (MU) triggered Pb-Pb collisions and corresponds to an integrated luminosity Lint 70 b1. The MU trigger requires a minimum bias (MB) trigger and at least a pair of opposite-sign (OS) track segments, each with a pT
above the threshold of the on-line trigger algorithm. This pT threshold was set to provide 50% efficiency for muon
tracks with pT ¼ 1 GeV=c. The MB trigger requires a
signal in both VZERO-A and VZERO-C. The beam-induced background was further reduced off-line using the VZERO and the zero degree calorimeter timing infor-mation. The contribution from electromagnetic processes was removed by requiring a minimum energy deposited in the neutron zero degree calorimeters [20]. The centrality determination is based on a fit of the VZERO amplitude distribution [21,22]. The average number of participating nucleons hNparti for the centrality classes used in this
analysis (see Table I) are derived from a Glauber model calculation [21,22].
J=c candidates are formed by combining pairs of OS tracks reconstructed in the geometrical acceptance of the muon spectrometer. To improve the muon identification, the reconstructed tracks in the tracking chambers are required to match a track segment in the trigger system above the pT threshold aforementioned.
The J=c v2 is calculated using event plane (EP) based
methods. The azimuthal angle of the second harmonic EP is used to estimate the reaction plane angle [23]. is determined from the azimuthal distribution of the VZERO amplitude. A two step flattening procedure of the EP azimuthal distribution was applied as described in [24] and [25], respectively. It results in an EP azimuthal distri-bution uniform to better than 2% for all centrality classes under study. The VZERO-C has a common acceptance region with the muon spectrometer. Therefore, only the VZERO-A was used for the EP determination to avoid autocorrelations. The J=c v2results were obtained
deter-mining v2 ¼ hcos2ð Þi versus the invariant mass
(m) [26], where is the OS dimuon azimuthal angle.
The resulting v2ðmÞ distribution is fitted using
v2ðmÞ ¼ vsig2 ðmÞ þ vbkg2 ðmÞ½1 ðmÞ; (1)
where vsig2 and vbkg2 correspond to the v2of the J=c signal
and of the background, respectively [see Fig. 1(b)]. vbkg2
was parametrized using a second order polynomial. Here, ðmÞ ¼ S=ðS þ BÞ is the ratio of the signal over the
sum of the signal plus background of the m
distribu-tions. It is extracted from fits to the OS invariant mass distribution [see Fig.1(a)] in each pT and centrality class.
The J=cline shape was described with a Crystal Ball (CB) function and the underlying continuum with either a third order polynomial or a Gaussian with a width linearly varying with mass. The CB function connects a Gaussian core with a power-law tail [27] at low mass to account for energy loss fluctuations and radiative decays. An extended CB function with an additional power-law tail at high mass, to account for alignment and calibration biases, was also used. The combination of several CB and under-lying continuum parametrizations described before were tested to assess the signal and the related systematic
TABLE I. hNparti and VZERO-A EP resolution for the centrality classes expressed in percentages of the nuclear cross section [21].
Centrality hNparti EP resolutionðstatÞ ðsystÞ
5%–20% 283 4 0:548 0:003 0:009 20%–40% 157 3 0:610 0:002 0:008 40%–60% 69 2 0:451 0:003 0:008 60%–90% 15 1 0:185 0:005 0:013 20%–60% 113 3 0:576 0:002 0:008 PRL111, 162301 (2013) P H Y S I C A L R E V I E W L E T T E R S 18 OCTOBER 2013
uncertainties. The J=c v2and its statistical uncertainty in
each pT and centrality class were determined as the
aver-age of the vsig2 obtained by fitting v2ðmÞ using Eq. (1)
with the various ðmÞ, while the corresponding
system-atic uncertainties were defined as the rms of these results. Figure1shows typical fits of the OS invariant mass distri-bution [1(a)] and of the hcos2ð Þi as a function of m [1(b)] in the 20%–40% centrality class. The
proce-dure above was repeated using either a first order poly-nomial or its inverse as vbkg2 parametrization. The largest
deviation of the results obtained with the three different vbkg2 parametrizations was conservatively adopted as the
systematic uncertainty related to the unknown shape of the vbkg2 ðmÞ. This turns out to often be the dominant source
of systematic uncertainties with the uncertainty from the signal extraction being the second one. It was checked that different choices of invariant mass binnings yield v2values
that are consistent within uncertainties. A similar method was used to extract the uncorrected (for detector accep-tance and efficiency) average transverse momentum (hpTiuncor) of the reconstructed J=c in each centrality and pT class. ThehpTiuncoris used to locate the data points
when plotted as a function of pT. Consistent v2values were
obtained using an alternative method [23] in which the J=c raw yield is extracted, as described before, in bins of ( ) and v2 is evaluated by fitting the data with
the functionðdN=dð ÞÞ ¼ A½1 þ 2v2cos2ð Þ, where A is a normalization constant. As an additional check the first analysis procedure [26] was also applied to the same-sign (SS) dimuons. As expected, no J=c signal is seen in either the invariant mass distribution or thehcos2ð Þi as a function of mof SS dimuons. In both cases the SS dimuons exhibit the same trend as the continuum of the OS dimuons.
The finite resolution in the EP determination smears out the azimuthal distributions and lowers the value of the measured anisotropy [23]. The VZERO-A EP resolution as a function of the centrality was determined using MB events and the 3 subevent method [23]. To estimate the systematic uncertainty from the EP determination two sets of 3 subevents were used: first, VZERO-A, VZERO-C, and the time projection chamber (TPC), with pseu-dorapidity gaps V0A-TPC¼ 1:9, V0A-V0C¼ 4:5, and TPC-V0C¼ 0:8; second, VZERO-A, ring 0 of
VZERO-C, and VZERO-C 3rd ring, with pseudorapi-dity gaps V0A-V0C0¼ 6:0, V0C0-V0C3¼ 1:0, and
V0A-V0C3 ¼ 4:5. The differences between the EP
reso-lution for VZERO-A obtained from these two sets of subevents are taken as systematic uncertainties. Since v2
is measured here in a wide centrality class, the resolution must reflect the distribution of events with a J=c within the class. Therefore, the EP resolution for each wide class was calculated as the average of the values obtained in finer centrality classes weighted by the number of recon-structed J=c. TableIshows the corresponding resolution for each centrality class which is applied to the results reported in this Letter.
The J=c reconstruction efficiency depends on the de-tector occupancy, which could bias the v2 measurement.
This effect was evaluated by embedding azimuthally iso-tropic simulated J=c ! þ decays into real events. The measured v2of those embedded J=c does not deviate
from zero by more than 0.015 in the centrality and pT
classes considered. This value is used as a conservative systematic uncertainty on all measured v2values.
Figure2shows the pTdependence of the inclusive J=c
v2for semicentral (20%–40%) Pb-Pb collisions atpffiffiffiffiffiffiffiffisNN ¼
2:76 TeV. The vertical bars show the statistical uncertain-ties while the boxes indicate the point-to-point uncorre-lated systematic uncertainties, which include those from
) c (GeV/ T p 0 1 2 3 4 5 6 7 8 9 10 2 v -0.1 0 0.1 0.2 0.3 < 4.0 y = 2.76 TeV), centrality 20%-40%, 2.5 < NN s ALICE (Pb-Pb 1.3% ± global syst =
FIG. 2 (color online). Inclusive J=c v2ðpTÞ for semicentral (20%–40%) Pb-Pb collisions atpffiffiffiffiffiffiffiffisNN¼ 2:76 TeV (see text for details on uncertainties). The used pTranges are 0–2, 2–4, 4–6, and 6–10 GeV=c. ) 2 c Counts/ (50 MeV/ 500 1000 1500 2000 (a) c < 4.0 GeV/ T p ≤ < 4.0, 2.0 y = 2.76 TeV, centrality 20% - 40%, 2.5 < NN s Pb-Pb
Opposite sign pairs Fit total Fit signal Fit background ) 2 c (GeV/ µ µ m 2 2.5 3 3.5 4 4.5 5 〉 ) Ψ - φ cos 2(〈 0 0.05
0.1 Opposite sign pairs
) µ µ m ( 2 v Fit total (b)
FIG. 1 (color online). Invariant mass distribution (a) and hcos2ð Þi as a function of m (b) of OS dimuons with 2 pT< 4 GeV=c and 2:5 < y < 4 in semicentral (20%–40%) Pb-Pb collisions.
the signal extraction, the vbkg2 shape, and the reconstruction
efficiency. The global correlated relative systematic uncer-tainty on the EP resolution is 1.3%. A nonzero v2 is
observed in the intermediate pT range 2 pT <
6 GeV=c. Including statistical and systematic uncertainties the combined significance of a nonzero v2in this pT range
is 2:7. At lower and higher pT the inclusive J=c v2 is
compatible with zero within uncertainties.
To study the centrality dependence of the v2 we select
J=c with 1:5 pT< 10 GeV=c. Indeed, below 1:5 GeV=c the v2 of the J=c is expected to be small
[15] and the signal to background ratio is also low. Since the initial spatial anisotropy for head-on collisions is small, the expected v2 is also small. In addition, for the 0%–5%
centrality range the VZERO-A EP resolution is quite low and has higher systematic uncertainties. Therefore, the 0%–5% centrality range was excluded. Figure3(a)shows v2 for inclusive J=c with 1:5 pT< 10 GeV=c as a
function of hNparti in Pb-Pb collisions at pffiffiffiffiffiffiffiffisNN ¼
2:76 TeV. Here, the point-to-point uncorrelated systematic uncertainties (boxes) also include, in addition to those discussed above, the uncertainty from the EP resolution determination. The measured v2 depends on the pT
distri-bution of the reconstructed J=c, which could vary with the collision centrality. Therefore, hpTiuncor of the recon-structed J=c is also shown in Fig. 3(b). The error bar indicates the statistical uncertainties while the boxes show the systematic uncertainties due to the J=c signal extraction. For the most central collisions, 5%–20% and 20%–40%, the inclusive J=c v2 for 1:5 pT <
10 GeV=c are 0:101 0:044ðstatÞ 0:032ðsystÞ and 0:116 0:045ðstatÞ 0:041ðsystÞ, respectively. The com-bined significance of a nonzero v2 is 2:9. For more
peripheral Pb-Pb collisions, the v2 is consistent with zero
within uncertainties. Although there is a small variation
with centrality, the hpTiuncor stays in the range 3:0–3:3 GeV=c, indicating that the bulk of the recon-structed J=c are in the same pT range for all centralities.
Thus, the observed centrality dependence of the v2 for
inclusive J=c with 1:5 pT< 10 GeV=c does not result
from any bias in the sampled pT distributions. For J=c
with pT< 1:5 GeV=c (not shown), the v2 is compatible
with zero within 1 standard deviation for the four centrality classes. The hpTiuncor ranges from about 0.75 to 0:9 GeV=c.
To allow a direct comparison with current model calcu-lations, the inclusive J=c v2ðpTÞ was also calculated in a
broader centrality range, namely, 20%–60%, and it is shown in Fig. 4. In this broader centrality range, the measured v2 signal in the pT range 2–4 GeV=c deviates
from zero by 2. The same trend of v2ðpTÞ is observed in
the 20%–60% and in the 20%–40% centrality classes. This trend seems qualitatively different from that of the STAR measurement [17] at lower collision energy, which is com-patible with zero for pT 2 GeV=c albeit in somewhat
different (10%–40% and 0%–80%) centrality ranges. Also shown in Fig.4are two transport model calculations that include a J=c regeneration component from deconfined charm quarks in the medium [15,28]. In both models about 30% of the measured J=c in the 20%–60% centrality range are regenerated. First, thermalized charm quarks in the medium transfer a significant elliptic flow to regener-ated J=c. Second, primordial J=c emitted out of plane traverse a longer path through the medium than those emitted in plane, resulting in a small apparent v2. The
predicted maximum v2 at pT 2:5 GeV=c results from
an interplay between the regeneration component, domi-nant at lower pT, and the primordial J=c component
which takes over at higher pT. The first model [28] is
shown for the hypothesis of thermalization (full line) and
〉 part N 〈 0 50 100 150 200 250 300 350 400 ) c (GeV/ uncor〉 T p〈 3 3.5 (b) 2 v -0.1 0 0.1 0.2 0.3 (a) c < 10.0 GeV/ T p ≤ < 4.0, 1.5 y = 2.76 TeV, 2.5 < NN s Pb-Pb
FIG. 3 (color online). v2(a) andhpTiuncor(b) of inclusive J=c with 1:5 pT< 10 GeV=c as a function of hNparti in Pb-Pb collisions at pffiffiffiffiffiffiffiffisNN¼ 2:76 TeV (see text for details on uncer-tainties). ) c (GeV/ T p 0 1 2 3 4 5 6 7 8 9 10 2 v -0.1 0 0.1 0.2 0.3 < 4.0 y = 2.76 TeV), centrality 20%-60%, 2.5 < NN s ALICE (Pb-Pb Y. Liu et al., b thermalized Y. Liu et al., b not thermalized X. Zhao et al., b thermalized
1.4% ± global syst =
FIG. 4 (color online). Inclusive J=c v2ðpTÞ for noncentral (20%–60%) Pb-Pb collisions atpffiffiffiffiffiffiffiffisNN¼ 2:76 TeV (see text for details on uncertainties). The used pTranges are 0–2, 2–4, 4–6, and 6–10 GeV=c. Calculations from two transport models [15,28] are also shown (see text for details).
nonthermalization (dashed line) of b quarks. The LHCb Collaboration measured the fraction of J=c from B hadron decays in pp collisions atpffiffis¼ 2:76 and 7 TeV [29,30] in the rapidity acceptance used for this measurement. At 7 TeV this fraction increases from 7% at pT 0 to 15%
at pT 7 GeV=c, while at 2.76 TeV it is about 7% for
pT< 12 GeV=c. In Pb-Pb collisions this fraction could
increase up to 11% if the B hadron RAA¼ 1. If b quarks
do thermalize, then their elliptic flow will be transferred to B mesons at hadronization and to the J=c at the B meson decay. In the second model [15] (dash-dotted line) only the case assuming b quark thermalization is shown. Both models qualitatively describe the pT dependence of the
v2 and the RAAof inclusive J=c [5].
In summary, we reported the ALICE measurement of inclusive J=c elliptic flow in the range 0 pT < 10 GeV=c at forward rapidity in Pb-Pb collisions atffiffiffiffiffiffiffiffi
sNN
p ¼ 2:76 TeV. For semicentral collisions indications of a nonzero J=c v2 are observed in the intermediate pT
range. This measurement complements the results on the J=c RAA, where a smaller suppression was seen at low pT
at the LHC compared to RHIC. Both results seem in agreement with the global picture in which a significant fraction of the observed J=c is produced from deconfined charm quarks in the QGP phase.
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 ac-celerator teams for the outstanding performance of the LHC complex. 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 Cientı´fico e Tecnolo´gico (CNPq), Financiadora de Estudos e Projetos (FINEP), Fundac¸a˜o de Amparo a` Pesquisa do Estado de Sa˜o Paulo (FAPESP); National Natural Science Foundation of China (NSFC), the Chinese Ministry of Education (CMOE), and 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, Me´xico, 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 Authority for Scientific Research-NASR (Autoritatea Nat¸ionala˘ pentru Cercetare S¸tiint¸ifica˘-ANCS); Ministry of Education and Science of Russian Federation, Russian Academy of Sciences, Russian Federal Agency of Atomic Energy, Russian Federal 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 Economı´a y Competitividad (MINECO) of Spain, Xunta de Galicia (Consellerı´a de Educacio´n), CEADEN, Cubaenergı´a, 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); U.S. Department of Energy, U.S. National Science Foundation, the State of Texas, and the State of Ohio.
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E. Abbas,1B. Abelev,2J. Adam,3D. Adamova´,4A. M. Adare,5M. M. Aggarwal,6G. Aglieri Rinella,7M. Agnello,8,9 A. G. Agocs,10A. Agostinelli,11Z. Ahammed,12N. Ahmad,13A. Ahmad Masoodi,13S. A. Ahn,14S. U. Ahn,14
I. Aimo,15,8,9M. Ajaz,16A. Akindinov,17D. Aleksandrov,18B. Alessandro,8A. Alici,19,20A. Alkin,21 E. Almara´z Avin˜a,22J. Alme,23T. Alt,24V. Altini,25S. Altinpinar,26I. Altsybeev,27C. Andrei,28A. Andronic,29
V. Anguelov,30J. Anielski,31C. Anson,32T. Anticˇic´,33F. Antinori,34P. Antonioli,19L. Aphecetche,35 H. Appelsha¨user,36N. Arbor,37S. Arcelli,11A. Arend,36N. Armesto,38R. Arnaldi,8T. Aronsson,5I. C. Arsene,29 M. Arslandok,36A. Asryan,27A. Augustinus,7R. Averbeck,29T. C. Awes,39J. A¨ ysto¨,40M. D. Azmi,13,41M. Bach,24 A. Badala`,42Y. W. Baek,43,44R. Bailhache,36R. Bala,45,8A. Baldisseri,46F. Baltasar Dos Santos Pedrosa,7J. Ba´n,47 R. C. Baral,48R. Barbera,49F. Barile,25G. G. Barnafo¨ldi,10L. S. Barnby,50V. Barret,43J. Bartke,51M. Basile,11 N. Bastid,43S. Basu,12B. Bathen,31G. Batigne,35B. Batyunya,52P. C. Batzing,53C. Baumann,36I. G. Bearden,54 H. Beck,36N. K. Behera,55I. Belikov,56F. Bellini,11R. Bellwied,57E. Belmont-Moreno,22G. Bencedi,10S. Beole,15 I. Berceanu,28A. Bercuci,28Y. Berdnikov,58D. Berenyi,10A. A. E. Bergognon,35R. A. Bertens,59D. Berzano,15,8 L. Betev,7A. Bhasin,45A. K. Bhati,6J. Bhom,60N. Bianchi,61L. Bianchi,15C. Bianchin,59J. Bielcˇı´k,3J. Bielcˇı´kova´,4
A. Bilandzic,54S. Bjelogrlic,59F. Blanco,57F. Blanco,62D. Blau,18C. Blume,36M. Boccioli,7S. Bo¨ttger,63 A. Bogdanov,64H. Bøggild,54M. Bogolyubsky,65L. Boldizsa´r,10M. Bombara,66J. Book,36H. Borel,46 A. Borissov,67F. Bossu´,41M. Botje,68E. Botta,15E. Braidot,69P. Braun-Munzinger,29M. Bregant,35T. Breitner,63 T. A. Broker,36T. A. Browning,70M. Broz,71R. Brun,7E. Bruna,15,8G. E. Bruno,25D. Budnikov,72H. Buesching,36 S. Bufalino,15,8P. Buncic,7O. Busch,30Z. Buthelezi,41D. Caffarri,73,34X. Cai,74H. Caines,5E. Calvo Villar,75
P. Camerini,76V. Canoa Roman,77G. Cara Romeo,19W. Carena,7F. Carena,7N. Carlin Filho,78F. Carminati,7 A. Casanova Dı´az,61J. Castillo Castellanos,46J. F. Castillo Hernandez,29E. A. R. Casula,79V. Catanescu,28 C. Cavicchioli,7C. Ceballos Sanchez,80J. Cepila,3P. Cerello,8B. Chang,40,81S. Chapeland,7J. L. Charvet,46 S. Chattopadhyay,82S. Chattopadhyay,12M. Cherney,83C. Cheshkov,7,84B. Cheynis,84V. Chibante Barroso,7 D. D. Chinellato,57P. Chochula,7M. Chojnacki,54S. Choudhury,12P. Christakoglou,68C. H. Christensen,54
P. Christiansen,85T. Chujo,60S. U. Chung,86C. Cicalo,87L. Cifarelli,11,20F. Cindolo,19J. Cleymans,41 F. Colamaria,25D. Colella,25A. Collu,79G. Conesa Balbastre,37Z. Conesa del Valle,7,88M. E. Connors,5 G. Contin,76J. G. Contreras,77T. M. Cormier,67Y. Corrales Morales,15P. Cortese,89I. Corte´s Maldonado,90 M. R. Cosentino,69F. Costa,7M. E. Cotallo,62E. Crescio,77P. Crochet,43E. Cruz Alaniz,22R. Cruz Albino,77
E. Cuautle,91L. Cunqueiro,61A. Dainese,73,34R. Dang,74A. Danu,92D. Das,82K. Das,82S. Das,93I. Das,88 A. Dash,94S. Dash,55S. De,12G. O. V. de Barros,78A. De Caro,95,20G. de Cataldo,96J. de Cuveland,24A. De Falco,79
D. De Gruttola,95,20H. Delagrange,35A. Deloff,97N. De Marco,8E. De´nes,10S. De Pasquale,95A. Deppman,78 G. D’Erasmo,25R. de Rooij,59M. A. Diaz Corchero,62D. Di Bari,25T. Dietel,31C. Di Giglio,25S. Di Liberto,98
A. Di Mauro,7P. Di Nezza,61R. Divia`,7Ø. Djuvsland,26A. Dobrin,67,85,59T. Dobrowolski,97B. Do¨nigus,29 O. Dordic,53O. Driga,35A. K. Dubey,12A. Dubla,59L. Ducroux,84P. Dupieux,43A. K. Dutta Majumdar,82D. Elia,96
D. Emschermann,31H. Engel,63B. Erazmus,7,35H. A. Erdal,23D. Eschweiler,24B. Espagnon,88M. Estienne,35 S. Esumi,60D. Evans,50S. Evdokimov,65G. Eyyubova,53D. Fabris,73,34J. Faivre,37D. Falchieri,11A. Fantoni,61
M. Fasel,30D. Fehlker,26L. Feldkamp,31D. Felea,92A. Feliciello,8B. Fenton-Olsen,69G. Feofilov,27 PRL111, 162301 (2013) P H Y S I C A L R E V I E W L E T T E R S 18 OCTOBER 2013
A. Ferna´ndez Te´llez,90A. Ferretti,15A. Festanti,73J. Figiel,51M. A. S. Figueredo,78S. Filchagin,72D. Finogeev,99 F. M. Fionda,25E. M. Fiore,25E. Floratos,100M. Floris,7S. Foertsch,41P. Foka,29S. Fokin,18E. Fragiacomo,101 A. Francescon,7,73U. Frankenfeld,29U. Fuchs,7C. Furget,37M. Fusco Girard,95J. J. Gaardhøje,54M. Gagliardi,15
A. Gago,75M. Gallio,15D. R. Gangadharan,32P. Ganoti,39C. Garabatos,29E. Garcia-Solis,102C. Gargiulo,7 I. Garishvili,2J. Gerhard,24M. Germain,35C. Geuna,46A. Gheata,7M. Gheata,92,7B. Ghidini,25P. Ghosh,12 P. Gianotti,61M. R. Girard,103P. Giubellino,7E. Gladysz-Dziadus,51P. Gla¨ssel,30R. Gomez,104,77E. G. Ferreiro,38
L. H. Gonza´lez-Trueba,22P. Gonza´lez-Zamora,62S. Gorbunov,24A. Goswami,105S. Gotovac,106 L. K. Graczykowski,103R. Grajcarek,30A. Grelli,59A. Grigoras,7C. Grigoras,7V. Grigoriev,64A. Grigoryan,107
S. Grigoryan,52B. Grinyov,21N. Grion,101P. Gros,85J. F. Grosse-Oetringhaus,7J.-Y. Grossiord,84R. Grosso,7 F. Guber,99R. Guernane,37B. Guerzoni,11M. Guilbaud,84K. Gulbrandsen,54H. Gulkanyan,107T. Gunji,108 A. Gupta,45R. Gupta,45R. Haake,31Ø. Haaland,26C. Hadjidakis,88M. Haiduc,92H. Hamagaki,108G. Hamar,10 B. H. Han,109L. D. Hanratty,50A. Hansen,54Z. Harmanova´-To´thova´,66J. W. Harris,5M. Hartig,36A. Harton,102 D. Hatzifotiadou,19S. Hayashi,108A. Hayrapetyan,7,107S. T. Heckel,36M. Heide,31H. Helstrup,23A. Herghelegiu,28 G. Herrera Corral,77N. Herrmann,30B. A. Hess,110K. F. Hetland,23B. Hicks,5B. Hippolyte,56Y. Hori,108P. Hristov,7
I. Hrˇivna´cˇova´,88M. Huang,26T. J. Humanic,32D. S. Hwang,109R. Ichou,43R. Ilkaev,72I. Ilkiv,97M. Inaba,60 E. Incani,79P. G. Innocenti,7G. M. Innocenti,15M. Ippolitov,18M. Irfan,13C. Ivan,29M. Ivanov,29V. Ivanov,58
A. Ivanov,27O. Ivanytskyi,21A. Jachołkowski,49P. M. Jacobs,69C. Jahnke,78H. J. Jang,14M. A. Janik,103 P. H. S. Y. Jayarathna,57S. Jena,55D. M. Jha,67R. T. Jimenez Bustamante,91P. G. Jones,50H. Jung,44A. Jusko,50
A. B. Kaidalov,17S. Kalcher,24P. Kalinˇa´k,47T. Kalliokoski,40A. Kalweit,7J. H. Kang,81V. Kaplin,64S. Kar,12 A. Karasu Uysal,7,111,112O. Karavichev,99T. Karavicheva,99E. Karpechev,99A. Kazantsev,18U. Kebschull,63 R. Keidel,113B. Ketzer,36,114S. A. Khan,12M. M. Khan,13P. Khan,82K. H. Khan,16A. Khanzadeev,58Y. Kharlov,65
B. Kileng,23M. Kim,81S. Kim,109M. Kim,44J. S. Kim,44J. H. Kim,109T. Kim,81B. Kim,81D. J. Kim,40 D. W. Kim,44,14S. Kirsch,24I. Kisel,24S. Kiselev,17A. Kisiel,103J. L. Klay,115J. Klein,30C. Klein-Bo¨sing,31 M. Kliemant,36A. Kluge,7M. L. Knichel,29A. G. Knospe,116M. K. Ko¨hler,29T. Kollegger,24A. Kolojvari,27 M. Kompaniets,27V. Kondratiev,27N. Kondratyeva,64A. Konevskikh,99V. Kovalenko,27M. Kowalski,51S. Kox,37
G. Koyithatta Meethaleveedu,55J. Kral,40I. Kra´lik,47F. Kramer,36A. Kravcˇa´kova´,66M. Krelina,3M. Kretz,24 M. Krivda,50,47F. Krizek,40M. Krus,3E. Kryshen,58M. Krzewicki,29V. Kucera,4Y. Kucheriaev,18T. Kugathasan,7 C. Kuhn,56P. G. Kuijer,68I. Kulakov,36J. Kumar,55P. Kurashvili,97A. Kurepin,99A. B. Kurepin,99A. Kuryakin,72
S. Kushpil,4V. Kushpil,4H. Kvaerno,53M. J. Kweon,30Y. Kwon,81P. Ladro´n de Guevara,91I. Lakomov,88 R. Langoy,26,117S. L. La Pointe,59C. Lara,63A. Lardeux,35P. La Rocca,49R. Lea,76M. Lechman,7S. C. Lee,44
G. R. Lee,50I. Legrand,7J. Lehnert,36R. C. Lemmon,118M. Lenhardt,29V. Lenti,96H. Leo´n,22M. Leoncino,15 I. Leo´n Monzo´n,104P. Le´vai,10S. Li,43,74J. Lien,26,117R. Lietava,50S. Lindal,53V. Lindenstruth,24C. Lippmann,29,7
M. A. Lisa,32H. M. Ljunggren,85D. F. Lodato,59P. I. Loenne,26V. R. Loggins,67V. Loginov,64D. Lohner,30 C. Loizides,69K. K. Loo,40X. Lopez,43E. Lo´pez Torres,80G. Løvhøiden,53X.-G. Lu,30P. Luettig,36M. Lunardon,73
J. Luo,74G. Luparello,59C. Luzzi,7R. Ma,5K. Ma,74D. M. Madagodahettige-Don,57A. Maevskaya,99 M. Mager,119,7D. P. Mahapatra,48A. Maire,30M. Malaev,58I. Maldonado Cervantes,91L. Malinina,52,120 D. Mal’Kevich,17P. Malzacher,29A. Mamonov,72L. Manceau,8L. Mangotra,45V. Manko,18F. Manso,43 N. Manukyan,107V. Manzari,96Y. Mao,74M. Marchisone,43,15J. Maresˇ,121G. V. Margagliotti,76,101A. Margotti,19
A. Marı´n,29C. Markert,116M. Marquard,36I. Martashvili,122N. A. Martin,29P. Martinengo,7M. I. Martı´nez,90 A. Martı´nez Davalos,22G. Martı´nez Garcı´a,35Y. Martynov,21A. Mas,35S. Masciocchi,29M. Masera,15A. Masoni,87
L. Massacrier,35A. Mastroserio,25A. Matyja,51C. Mayer,51J. Mazer,122M. A. Mazzoni,98F. Meddi,123 A. Menchaca-Rocha,22J. Mercado Pe´rez,30M. Meres,71Y. Miake,60K. Mikhaylov,52,17L. Milano,7,15 J. Milosevic,53,124A. Mischke,59A. N. Mishra,105,125D. Mis´kowiec,29C. Mitu,92S. Mizuno,60J. Mlynarz,67 B. Mohanty,12,126L. Molnar,10,56L. Montan˜o Zetina,77M. Monteno,8E. Montes,62T. Moon,81M. Morando,73 D. A. Moreira De Godoy,78S. Moretto,73A. Morreale,40A. Morsch,7V. Muccifora,61E. Mudnic,106S. Muhuri,12
M. Mukherjee,12H. Mu¨ller,7M. G. Munhoz,78S. Murray,41L. Musa,7J. Musinsky,47B. K. Nandi,55R. Nania,19 E. Nappi,96C. Nattrass,122T. K. Nayak,12S. Nazarenko,72A. Nedosekin,17M. Nicassio,25,29M. Niculescu,92,7 B. S. Nielsen,54T. Niida,60S. Nikolaev,18V. Nikolic,33S. Nikulin,18V. Nikulin,58B. S. Nilsen,83M. S. Nilsson,53 F. Noferini,19,20P. Nomokonov,52G. Nooren,59A. Nyanin,18A. Nyatha,55C. Nygaard,54J. Nystrand,26A. Ochirov,27
H. Oeschler,119,7,30S. Oh,5S. K. Oh,44J. Oleniacz,103A. C. Oliveira Da Silva,78C. Oppedisano,8 A. Ortiz Velasquez,85,91A. Oskarsson,85P. Ostrowski,103J. Otwinowski,29K. Oyama,30K. Ozawa,108 PRL111, 162301 (2013) P H Y S I C A L R E V I E W L E T T E R S 18 OCTOBER 2013
Y. Pachmayer,30M. Pachr,3F. Padilla,15P. Pagano,95G. Paic´,91F. Painke,24C. Pajares,38S. K. Pal,12A. Palaha,50 A. Palmeri,42V. Papikyan,107G. S. Pappalardo,42W. J. Park,29A. Passfeld,31D. I. Patalakha,65V. Paticchio,96 B. Paul,82A. Pavlinov,67T. Pawlak,103T. Peitzmann,59H. Pereira Da Costa,46E. Pereira De Oliveira Filho,78 D. Peresunko,18C. E. Pe´rez Lara,68D. Perrino,25W. Peryt,103A. Pesci,19Y. Pestov,127V. Petra´cˇek,3M. Petran,3 M. Petris,28P. Petrov,50M. Petrovici,28C. Petta,49S. Piano,101M. Pikna,71P. Pillot,35O. Pinazza,7L. Pinsky,57
N. Pitz,36D. B. Piyarathna,57M. Planinic,33M. Płoskon´,69J. Pluta,103T. Pocheptsov,52S. Pochybova,10 P. L. M. Podesta-Lerma,104M. G. Poghosyan,7K. Pola´k,121B. Polichtchouk,65N. Poljak,59,33A. Pop,28 S. Porteboeuf-Houssais,43V. Pospı´sˇil,3B. Potukuchi,45S. K. Prasad,67R. Preghenella,19,20F. Prino,8C. A. Pruneau,67 I. Pshenichnov,99G. Puddu,79V. Punin,72M. Putisˇ,66J. Putschke,67H. Qvigstad,53A. Rachevski,101A. Rademakers,7
T. S. Ra¨iha¨,40J. Rak,40A. Rakotozafindrabe,46L. Ramello,89S. Raniwala,105R. Raniwala,105S. S. Ra¨sa¨nen,40 B. T. Rascanu,36D. Rathee,6W. Rauch,7K. F. Read,122J. S. Real,37K. Redlich,97,128R. J. Reed,5A. Rehman,26 P. Reichelt,36M. Reicher,59R. Renfordt,36A. R. Reolon,61A. Reshetin,99F. Rettig,24J.-P. Revol,7K. Reygers,30
L. Riccati,8R. A. Ricci,129T. Richert,85M. Richter,53P. Riedler,7W. Riegler,7F. Riggi,49,42 M. Rodrı´guez Cahuantzi,90A. Rodriguez Manso,68K. Røed,26,53E. Rogochaya,52D. Rohr,24D. Ro¨hrich,26 R. Romita,29,118F. Ronchetti,61P. Rosnet,43S. Rossegger,7A. Rossi,7,73P. Roy,82C. Roy,56A. J. Rubio Montero,62 R. Rui,76R. Russo,15E. Ryabinkin,18A. Rybicki,51S. Sadovsky,65K. Sˇafarˇı´k,7R. Sahoo,125P. K. Sahu,48J. Saini,12
H. Sakaguchi,130S. Sakai,69D. Sakata,60C. A. Salgado,38J. Salzwedel,32S. Sambyal,45V. Samsonov,58 X. Sanchez Castro,56L. Sˇa´ndor,47A. Sandoval,22M. Sano,60G. Santagati,49R. Santoro,7,20J. Sarkamo,40 D. Sarkar,12E. Scapparone,19F. Scarlassara,73R. P. Scharenberg,70C. Schiaua,28R. Schicker,30H. R. Schmidt,110 C. Schmidt,29S. Schuchmann,36J. Schukraft,7T. Schuster,5Y. Schutz,7,35K. Schwarz,29K. Schweda,29G. Scioli,11
E. Scomparin,8R. Scott,122P. A. Scott,50G. Segato,73I. Selyuzhenkov,29S. Senyukov,56J. Seo,86S. Serci,79 E. Serradilla,62,22A. Sevcenco,92A. Shabetai,35G. Shabratova,52R. Shahoyan,7N. Sharma,122S. Sharma,45 S. Rohni,45K. Shigaki,130K. Shtejer,80Y. Sibiriak,18E. Sicking,31S. Siddhanta,87T. Siemiarczuk,97D. Silvermyr,39
C. Silvestre,37G. Simatovic,91,33G. Simonetti,7R. Singaraju,12R. Singh,45S. Singha,12,126V. Singhal,12 B. C. Sinha,12T. Sinha,82B. Sitar,71M. Sitta,89T. B. Skaali,53K. Skjerdal,26R. Smakal,3N. Smirnov,5 R. J. M. Snellings,59C. Søgaard,85R. Soltz,2M. Song,81J. Song,86C. Soos,7F. Soramel,73I. Sputowska,51
M. Spyropoulou-Stassinaki,100B. K. Srivastava,70J. Stachel,30I. Stan,92G. Stefanek,97M. Steinpreis,32 E. Stenlund,85G. Steyn,41J. H. Stiller,30D. Stocco,35M. Stolpovskiy,65P. Strmen,71A. A. P. Suaide,78 M. A. Subieta Va´squez,15T. Sugitate,130C. Suire,88R. Sultanov,17M. Sˇumbera,4T. Susa,33T. J. M. Symons,69 A. Szanto de Toledo,78I. Szarka,71A. Szczepankiewicz,51,7M. Szyman´ski,103J. Takahashi,94M. A. Tangaro,25 J. D. Tapia Takaki,88A. Tarantola Peloni,36A. Tarazona Martinez,7A. Tauro,7G. Tejeda Mun˜oz,90A. Telesca,7
A. Ter Minasyan,18C. Terrevoli,25J. Tha¨der,29D. Thomas,59R. Tieulent,84A. R. Timmins,57D. Tlusty,3 A. Toia,24,73,34H. Torii,108L. Toscano,8V. Trubnikov,21D. Truesdale,32W. H. Trzaska,40T. Tsuji,108A. Tumkin,72
R. Turrisi,34T. S. Tveter,53J. Ulery,36K. Ullaland,26J. Ulrich,131,63A. Uras,84G. M. Urciuoli,98G. L. Usai,79 M. Vajzer,3,4M. Vala,52,47L. Valencia Palomo,88P. Vande Vyvre,7J. W. Van Hoorne,7M. van Leeuwen,59
L. Vannucci,129A. Vargas,90R. Varma,55M. Vasileiou,100A. Vasiliev,18V. Vechernin,27M. Veldhoen,59 M. Venaruzzo,76E. Vercellin,15S. Vergara,90R. Vernet,132M. Verweij,59L. Vickovic,106G. Viesti,73 J. Viinikainen,40Z. Vilakazi,41O. Villalobos Baillie,50Y. Vinogradov,72L. Vinogradov,27A. Vinogradov,18 T. Virgili,95Y. P. Viyogi,12A. Vodopyanov,52M. A. Vo¨lkl,30S. Voloshin,67K. Voloshin,17G. Volpe,7B. von Haller,7
I. Vorobyev,27D. Vranic,29,7J. Vrla´kova´,66B. Vulpescu,43A. Vyushin,72B. Wagner,26V. Wagner,3R. Wan,74 Y. Wang,74M. Wang,74Y. Wang,30K. Watanabe,60M. Weber,57J. P. Wessels,7,31U. Westerhoff,31J. Wiechula,110
J. Wikne,53M. Wilde,31G. Wilk,97M. C. S. Williams,19B. Windelband,30L. Xaplanteris Karampatsos,116 C. G. Yaldo,67Y. Yamaguchi,108S. Yang,26P. Yang,74H. Yang,46,59S. Yasnopolskiy,18J. Yi,86Z. Yin,74
I.-K. Yoo,86J. Yoon,81W. Yu,36X. Yuan,74I. Yushmanov,18V. Zaccolo,54C. Zach,3C. Zampolli,19 S. Zaporozhets,52A. Zarochentsev,27P. Za´vada,121N. Zaviyalov,72H. Zbroszczyk,103P. Zelnicek,63 I. S. Zgura,92M. Zhalov,58H. Zhang,74X. Zhang,69,43,74Y. Zhang,74D. Zhou,74F. Zhou,74Y. Zhou,59H. Zhu,74
J. Zhu,74X. Zhu,74J. Zhu,74A. Zichichi,11,20A. Zimmermann,30G. Zinovjev,21Y. Zoccarato,84 M. Zynovyev,21and M. Zyzak36
(ALICE Collaboration)
1Academy of Scientific Research and Technology (ASRT), Cairo, Egypt 2Lawrence Livermore National Laboratory, Livermore, California, USA
3Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague, Czech Republic 4Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Rˇ ezˇu Prahy, Czech Republic
5Yale University, New Haven, Connecticut, USA 6Physics Department, Panjab University, Chandigarh, India 7European Organization for Nuclear Research (CERN), Geneva, Switzerland
8Sezione INFN, Turin, Italy 9
Politecnico di Torino, Turin, Italy
10Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest, Hungary 11Dipartimento di Fisica e Astronomia dell’Universita` and Sezione INFN, Bologna, Italy
12Variable Energy Cyclotron Centre, Kolkata, India 13Department of Physics, Aligarh Muslim University, Aligarh, India 14Korea Institute of Science and Technology Information, Daejeon, South Korea
15Dipartimento di Fisica dell’Universita` and Sezione INFN, Turin, Italy 16COMSATS Institute of Information Technology (CIIT), Islamabad, Pakistan
17Institute for Theoretical and Experimental Physics, Moscow, Russia 18Russian Research Centre Kurchatov Institute, Moscow, Russia
19Sezione INFN, Bologna, Italy
20Centro Fermi-Museo Storico della Fisica e Centro Studi e Ricerche ‘‘Enrico Fermi,’’ Rome, Italy 21Bogolyubov Institute for Theoretical Physics, Kiev, Ukraine
22Instituto de Fı´sica, Universidad Nacional Auto´noma de Me´xico, Mexico City, Mexico 23Faculty of Engineering, Bergen University College, Bergen, Norway
24Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe-Universita¨t Frankfurt, Frankfurt, Germany 25
Dipartimento Interateneo di Fisica ‘‘M. Merlin’’ and Sezione INFN, Bari, Italy 26Department of Physics and Technology, University of Bergen, Bergen, Norway 27V. Fock Institute for Physics, St. Petersburg State University, St. Petersburg, Russia
28National Institute for Physics and Nuclear Engineering, Bucharest, Romania
29Research Division and ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum fu¨r Schwerionenforschung, Darmstadt, Germany 30Physikalisches Institut, Ruprecht-Karls-Universita¨t Heidelberg, Heidelberg, Germany
31Institut fu¨r Kernphysik, Westfa¨lische Wilhelms-Universita¨t Mu¨nster, Mu¨nster, Germany 32Department of Physics, The Ohio State University, Columbus, Ohio, USA
33Rudjer Bosˇkovic´ Institute, Zagreb, Croatia 34Sezione INFN, Padova, Italy
35SUBATECH, Ecole des Mines de Nantes, Universite´ de Nantes, CNRS-IN2P3, Nantes, France 36Institut fu¨r Kernphysik, Johann Wolfgang Goethe-Universita¨t Frankfurt, Frankfurt, Germany 37Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Universite´ Joseph Fourier,
CNRS-IN2P3, Institut Polytechnique de Grenoble, Grenoble, France
38Departamento de Fı´sica de Partı´culas and IGFAE, Universidad de Santiago de Compostela, Santiago de Compostela, Spain 39Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
40Helsinki Institute of Physics (HIP) and University of Jyva¨skyla¨, Jyva¨skyla¨, Finland
41Physics Department, University of Cape Town and iThemba LABS, National Research Foundation, Somerset West, South Africa 42Sezione INFN, Catania, Italy
43Laboratoire de Physique Corpusculaire (LPC), Clermont Universite´, Universite´ Blaise Pascal, CNRS–IN2P3, Clermont-Ferrand, France
44Gangneung-Wonju National University, Gangneung, South Korea 45Physics Department, University of Jammu, Jammu, India 46
Commissariat a` l’Energie Atomique, IRFU, Saclay, France
47Institute of Experimental Physics, Slovak Academy of Sciences, Kosˇice, Slovakia 48Institute of Physics, Bhubaneswar, India
49Dipartimento di Fisica e Astronomia dell’Universita` and Sezione INFN, Catania, Italy 50School of Physics and Astronomy, University of Birmingham, Birmingham, United Kingdom 51The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Cracow, Poland
52Joint Institute for Nuclear Research (JINR), Dubna, Russia 53Department of Physics, University of Oslo, Oslo, Norway 54Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
55
Indian Institute of Technology Bombay (IIT), Mumbai, India
56Institut Pluridisciplinaire Hubert Curien (IPHC), Universite´ de Strasbourg, CNRS-IN2P3, Strasbourg, France 57University of Houston, Houston, Texas, USA
58Petersburg Nuclear Physics Institute, Gatchina, Russia
59Nikhef, National Institute for Subatomic Physics and Institute for Subatomic Physics of Utrecht University, Utrecht, Netherlands
60University of Tsukuba, Tsukuba, Japan 61Laboratori Nazionali di Frascati, INFN, Frascati, Italy
62Centro de Investigaciones Energe´ticas Medioambientales y Tecnolo´gicas (CIEMAT), Madrid, Spain 63Institut fu¨r Informatik, Johann Wolfgang Goethe-Universita¨t Frankfurt, Frankfurt, Germany
64Moscow Engineering Physics Institute, Moscow, Russia 65Institute for High Energy Physics, Protvino, Russia 66Faculty of Science, P.J. Sˇafa´rik University, Kosˇice, Slovakia
67Wayne State University, Detroit, Michigan, USA 68
Nikhef, National Institute for Subatomic Physics, Amsterdam, Netherlands 69Lawrence Berkeley National Laboratory, Berkeley, California, USA
70Purdue University, West Lafayette, Indiana, USA
71Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovakia 72Russian Federal Nuclear Center (VNIIEF), Sarov, Russia
73Dipartimento di Fisica e Astronomia dell’Universita` and Sezione INFN, Padova, Italy 74Central China Normal University, Wuhan, China
75Seccio´n Fı´sica, Departamento de Ciencias, Pontificia Universidad Cato´lica del Peru´, Lima, Peru 76Dipartimento di Fisica dell’Universita` and Sezione INFN, Trieste, Italy
77Centro de Investigacio´n y de Estudios Avanzados (CINVESTAV), Mexico City and Me´rida, Mexico 78Universidade de Sa˜o Paulo (USP), Sa˜o Paulo, Brazil
79Dipartimento di Fisica dell’Universita` and Sezione INFN, Cagliari, Italy 80Centro de Aplicaciones Tecnolo´gicas y Desarrollo Nuclear (CEADEN), Havana, Cuba
81Yonsei University, Seoul, South Korea 82Saha Institute of Nuclear Physics, Kolkata, India
83Physics Department, Creighton University, Omaha, Nebraska, USA 84
Universite´ de Lyon, Universite´ Lyon 1, CNRS/IN2P3, IPN-Lyon, Villeurbanne, France 85Division of Experimental High Energy Physics, University of Lund, Lund, Sweden
86Pusan National University, Pusan, South Korea 87Sezione INFN, Cagliari, Italy
88Institut de Physique Nucle´aire d’Orsay (IPNO), Universite´ Paris-Sud, CNRS-IN2P3, Orsay, France 89Dipartimento di Scienze e Innovazione Tecnologica dell’Universita` del Piemonte Orientale
and Gruppo Collegato INFN, Alessandria, Italy 90Beneme´rita Universidad Auto´noma de Puebla, Puebla, Mexico
91Instituto de Ciencias Nucleares, Universidad Nacional Auto´noma de Me´xico, Mexico City, Mexico 92Institute of Space Sciences (ISS), Bucharest, Romania
93Bose Institute, Department of Physics and Centre for Astroparticle Physics and Space Science (CAPSS), Kolkata, India 94Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil
95Dipartimento di Fisica ‘‘E.R. Caianiello‘‘ dell’Universita` and Gruppo Collegato INFN, Salerno, Italy 96Sezione INFN, Bari, Italy
97National Centre for Nuclear Studies, Warsaw, Poland 98Sezione INFN, Rome, Italy
99Institute for Nuclear Research, Academy of Sciences, Moscow, Russia 100Physics Department, University of Athens, Athens, Greece
101Sezione INFN, Trieste, Italy
102Chicago State University, Chicago, Illinois, USA 103Warsaw University of Technology, Warsaw, Poland 104Universidad Auto´noma de Sinaloa, Culiaca´n, Mexico 105Physics Department, University of Rajasthan, Jaipur, India
106
Technical University of Split FESB, Split, Croatia
107A. I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Foundation, Yerevan, Armenia 108University of Tokyo, Tokyo, Japan
109Department of Physics, Sejong University, Seoul, South Korea 110Eberhard Karls Universita¨t Tu¨bingen, Tu¨bingen, Germany
111Yildiz Technical University, Istanbul, Turkey 112KTO Karatay University, Konya, Turkey
113Zentrum fu¨r Technologietransfer und Telekommunikation (ZTT), Fachhochschule Worms, Worms, Germany 114Technische Universita¨t Mu¨nchen, Munich, Germany
115
California Polytechnic State University, San Luis Obispo, California, USA 116The University of Texas at Austin, Physics Department, Austin, Texas, USA
117Vestfold University College, Tonsberg, Norway
118Nuclear Physics Group, STFC Daresbury Laboratory, Daresbury, United Kingdom 119Institut fu¨r Kernphysik, Technische Universita¨t Darmstadt, Darmstadt, Germany
120M.V. Lomonosov Moscow State University, D.V. Skobeltsyn Institute of Nuclear Physics, Moscow, Russia 121Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
122University of Tennessee, Knoxville, Tennessee, USA
123Dipartimento di Fisica dell’Universita` ‘‘La Sapienza’’ and Sezione INFN, Rome, Italy 124University of Belgrade, Faculty of Physics and ‘‘Vina’’ Institute of Nuclear Sciences, Belgrade, Serbia
125Indian Institute of Technology Indore (IITI), Indore, India 126National Institute of Science Education and Research, Bhubaneswar, India
127Budker Institute for Nuclear Physics, Novosibirsk, Russia 128
Institut of Theoretical Physics, University of Wroclaw, Wroclaw, Poland 129Laboratori Nazionali di Legnaro, INFN, Legnaro, Italy
130Hiroshima University, Hiroshima, Japan
131Kirchhoff-Institut fu¨r Physik, Ruprecht-Karls-Universita¨t Heidelberg, Heidelberg, Germany 132Centre de Calcul de l’IN2P3, Villeurbanne, France
