Higher harmonic anisotropic flow measurements of charged particles in Pb-Pb collisions at root s(NN)=2.76 TeV

Higher Harmonic Anisotropic Flow Measurements of Charged Particles in Pb-Pb Collisions at p ffiffiffiffiffiffiffiffiffi s

¼ 2:76 TeV

K. Aamodtet al.* (ALICE Collaboration)

(Received 19 May 2011; published 11 July 2011)

We report on the first measurement of the triangularv3, quadrangularv4, and pentagonalv5charged particle flow in Pb-Pb collisions at ffiffiffiffiffiffiffiffi

sNN

p ¼2:76 TeVmeasured with the ALICE detector at the CERN Large Hadron Collider. We show that the triangular flow can be described in terms of the initial spatial anisotropy and its fluctuations, which provides strong constraints on its origin. In the most central events, where the elliptic flowv2andv3have similar magnitude, a double peaked structure in the two-particle azimuthal correlations is observed, which is often interpreted as a Mach cone response to fast partons. We show that this structure can be naturally explained from the measured anisotropic flow Fourier coefficients.

DOI:10.1103/PhysRevLett.107.032301 PACS numbers: 25.75.Ld, 05.70.Fh, 25.75.Gz

The quark-gluon plasma is a state of matter whose existence at high-energy density is predicted by quantum chromodynamics. The creation of this state of matter in the laboratory and the study of its properties are the main goals of the ultrarelativistic nuclear collision program. One of the experimental observables that is sensitive to the prop- erties of this matter is the azimuthal distribution of parti- cles in the plane perpendicular to the beam direction. When nuclei collide at nonzero impact parameter (noncentral collisions), the geometrical overlap region is anisotropic.

This initial spatial asymmetry is converted via multiple collisions into an anisotropic momentum distribution of the produced particles [1].

The azimuthal anisotropy is usually characterized by the Fourier coefficients [2,3]:

vn¼ hcos½nð_nÞi; (1) where is the azimuthal angle of the particle,_n is the angle of the initial state spatial plane of symmetry, andnis the order of the harmonic. Because the planes of symmetry _n are not known experimentally, the anisotropic flow coefficients are estimated from measured correlations be- tween the observed particles. The second Fourier coeffi- cientv2is called elliptic flow and has been studied in detail in recent years [4]. Large values of elliptic flow at the LHC were recently observed by the ALICE Collaboration [5].

In a noncentral heavy ion collision the beam axis and the impact parameter define the reaction plane_RP. Assuming a smooth matter distribution in the colliding nuclei, the plane of symmetry is the reaction plane_n ¼_RPand the

odd Fourier coefficients are zero by symmetry. However, due to fluctuations in the matter distribution, including contributions from fluctuations in the positions of the participating nucleons in the nuclei, the plane of symmetry fluctuates event by event around the reaction plane. This plane of symmetry is determined by the participating nu- cleons and is therefore called the participant plane_PP[6].

Event-by-event fluctuations of the spatial asymmetry gen- erate additional odd harmonic symmetry planes_n, which are predicted to give rise to the odd harmonics likev3and v5 [7–13].

The large elliptic flow at the Relativistic Heavy Ion Collider (RHIC) [14,15] and at the LHC [5] provides compelling evidence for strongly interacting matter which appears to behave like an almost perfect (inviscid) fluid [16]. Deviations from this ideal case are controlled by the ratio=sof shear viscosity to entropy density. Because the effect of shear viscosity is to dampen all coefficients, with a larger decrease for higher order coefficients [12,17], it has been argued that the magnitude and transverse mo- mentum dependence of the coefficientsv3andv5is a more sensitive measure of=s[11]. Therefore a measurement of these Fourier coefficients at the LHC provides strong con- straints on the initial geometry, its fluctuations, as well as on the shear viscosity to entropy density ratio.

In this Letter we report the first measurement of the anisotropic flow coefficients v3, v4, and v5 of charged particles in Pb-Pb collisions at the center of mass energy per nucleon pair ffiffiffiffiffiffiffiffi

sNN

p ¼2:76 TeV, with the ALICE de- tector [18–20]. The data were recorded in November 2010 during the first run with heavy ions at the LHC.

For this analysis the ALICE inner tracking system (ITS) and the time projection chamber (TPC) were used to reconstruct charged particle tracks. The VZERO counters and the silicon pixel detector (SPD) were used for the trigger. The VZERO counters are two scintillator arrays providing both amplitude and timing information, covering

*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 attribution to the author(s) and the published article’s title, journal citation, and DOI.

the pseudorapidity range 2:8< <5:1(VZERO-A) and 3:7< <1:7(VZERO-C). The SPD is the innermost part of the ITS, consisting of two cylindrical layers of hybrid silicon pixel assemblies covering the range ofjj<

2:0 and jj<1:4 for the inner and outer layer, respec- tively. The minimum-bias interaction trigger required the following three conditions [21]: (i) two pixel chip hits in the outer layer of the silicon pixel detectors, (ii) a signal in VZERO-A, and (iii) a signal in VZERO-C. Deflection of neutral recoils, which is sensitive to the directed flow of spectators, is measured with two neutron zero degree cal- orimeters (ZDCs) installed on each side, 114 m from the interaction point. Only events with a vertex found within 7 cm from the center of the detector along the beam line were used in the analysis. This is to ensure a uniform acceptance in the central pseudorapidity region jj<

0:8. An event sample of510⁶ Pb-Pb collisions passed the selection criteria and was analyzed as a function of collision centrality, determined by cuts on the VZERO multiplicity as described in [21]. Based on the strong correlation between the collision centrality determined by the ZDC, TPC, SPD, and VZERO detectors, the resolution in centrality is found to be<0:5%rms for the most central collisions (0%–5%), increasing towards 2% rms for pe- ripheral collisions (e.g., 70%–80%). This resolution is also in agreement with our Monte Carlo (MC) Glauber [22]

studies.

The analysis was, as in [5], performed using tracks measured with only the TPC and for tracks using the ITS and TPC. These two measurements have very different acceptance and efficiency corrections, and provide an es- timate of a possible residual bias which may be present, after correction, for small values of the harmonics [23]. For both measurements, charged particles were selected with high reconstruction efficiency and minimal contamination from photon conversions and secondary charged particles produced in the detector material as described in [5]. From Monte Carlo simulations of HIJING [24] events using a

GEANT3[25] detector simulation and event reconstruction, the estimated contamination is less than 6% at pt¼ 0:2 GeV=cand drops below 1% atp_t>1 GeV=c. In this Letter we present the results obtained using the TPC stand- alone tracks, because of the smaller corrections for the azimuthal acceptance.

We report the anisotropic flow coefficientsvnobtained from two-particle correlations and from a four-particle cumulant method [26], denoted vnf2g and vnf4g, respec- tively. To calculate the four-particle cumulants we used the method proposed in [23]. The v_nf2g and v_nf4g measure- ments have different sensitivity to flow fluctuations and contributions from nonflow. The nonflow contribution arises from correlations between the particles unrelated to the initial geometry. The contribution from flow fluctua- tions is positive forv_nf2gwhile it is negative forv_nf4g[27].

Because the odd harmonics are expected to be completely

due to event-by-event fluctuations in the initial spatial geometry, the comparison of these two- and four-particle cumulants provides a strong constraint on the initial spatial geometry fluctuations.

The nonflow contribution to the two-particle correla- tions is not known and might be significant. We utilize four methods to study and correct for nonflow contribu- tions to thevnf2gcoefficients. First, we comparevnf2gfor like and unlike charge-sign combinations since they have different contributions from resonance decay and jet frag- mentation. Second, we used different pseudorapidity gap requirements between the two particles since larger gaps reduce the nonflow contributions. Third, we utilizeHIJING

(a perturbative quantum chromodynamics inspired model which does not include flow) to estimate these contribu- tions, and, finally, we estimate the nonflow from the corre- lations measured in proton-proton collisions. All of these methods indicate that nonflow effects are smaller than 10%. In this Letter we use the dependence of the correla- tions on pseudorapidity distance between particles as an estimate of nonflow.

Figure1(a)showsv2, v3, andv4 integrated over thept

range0:2< pt<5:0 GeV=cas a function of centrality. The v2f2g,v3f2g, andv4f2gare shown for particles withjj>

1:0and corrected for the estimated remaining nonflow con- tribution based on the correlation measured in HIJING. The total systematic uncertainty is shown as a band and fully includes this residual correction. The measuredv3is smaller thanv2and does not depend strongly on centrality. Thev3is compatible with predictions for Pb-Pb collisions from a hydrodynamic model calculation with Glauber initial con- ditions and =s¼0:08 and larger than for MC-KLN (Kharzeev-Levin-Nardi) color glass condensate (CGC) [28]

initial conditions with=s¼0:16 [11], suggesting a small value of =sfor the matter created in these collisions. The v3f4g is about a factor 2 smaller than the two-particle measurement which can, as explained in [29], be understood ifv3 originates predominantly from event-by-event fluctua- tions of the initial spatial geometry. For these event-by-event fluctuations of the spatial geometry, the symmetry plane₃ is expected to be uncorrelated (or correlated very weakly [30]) with the reaction plane_RPand with₂. We evaluate the correlations between₃ and _RP using the first-order event plane from the ZDC viav3=RP ¼ hcosð313_RPÞi and the correlation between₃ and₂ with a five-particle correlator hcosð31þ32232425Þi=v³2 ¼ v²₃₌₂. In Fig.1(a)v_3=RP andv²₃₌₂ are shown as a function of centrality. These correlations are indeed, within uncertain- ties, consistent with zero, as expected from a triangular flow that originates predominantly from event-by-event fluctua- tions of the initial spatial geometry.

To investigate the role of viscosity further we calculate the ratios v2="2 and v3="3, where "2 and "3 are the ellipticity and triangularity of the initial spatial geometry, defined by

"_n¼ hr²cosnð_nÞi

hr²i ; (2)

where the brackets denote an average which traditionally is taken over the position of participating (wounded) nucle- ons in a Glauber model [22].

Under the assumption thatv_nis proportional to"_n,v_nf2g is proportional to"_nf2g[27]. Figure1(b)shows the ratios v_n="_n for eccentricities calculated with a Glauber and a MC-KLN CGC [28] model, denoted by "^Wnf2g and

"^CGCn f2g, respectively. We find that for a Glauber model the magnitude ofv3f2g="3f2gis smaller thanv2f2g="2f2g, which would indicate significant viscous corrections. For

MC-KLN CGC calculations the ratios v2f2g="2f2g and v3f2g="3f2g are almost equal for the most central colli- sions, as expected for an almost ideal fluid [11]. In addition, we notice that the ratio v3f2g="3f2g decreases faster thanv2f2g="2f2gtoward more peripheral collisions, which is expected due to larger viscous corrections tov3. The centrality dependence of the triangular flow differs significantly from that of elliptic flow. This might be due to two reasons: either the centrality dependence of the spatial ellipticity and triangularity are different and/or the viscous effects are different. However, in a small centrality range, such as 0%–5%, viscous effects do not change much and there one might be directly sensitive to the change in the initial spatial geometry. Our calculations show that even in this small centrality range, the ratio"2="3changes signifi- cantly, which allows us to investigate further the geomet- rical origin of elliptical and triangular flow. In Fig.2v2f2g andv3f2gare plotted in 1% centrality bins for the 5% most central collisions. We observe that v3f2g does not change much versus centrality (as would be expected if v3 is dominated by event-by-event fluctuations of the initial geometry) whilev2f2gincreases by about 60%. We com- pare this dependence ofv_nf2gto the centrality dependence of the eccentricities"_nf2gfor initial conditions from MC- KLN CGC and Monte Carlo Glauber model. We observe that the weak dependence of v3f2g is described by both calculations while the relative strong dependence ofv2f2g on centrality is only described for the MC-KLN CGC initial conditions.

The harmonicsv2f2g,v3f2g,v4f2g, andv5f2gas a func- tion of transverse momentum are shown for the 30%–40%, 0%–5%, and 0%–2% centrality classes in Fig. 3. For the 30%–40% centrality class the results are compared to hydrodynamic predictions using Glauber initial conditions for different values of=s[31]. We observe that, at lowp_t, the different pt dependence of v2 and v3 is described well by these hydrodynamic predictions. However, the

centrality percentile

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

0.015 0.02 0.025 0.03 0.035

| > 1}

η

∆ {2, | v2

| > 1}

η

∆ {2, | v3

CGC{2}

εn 1,n× k

W{2}

εn 2,n× k

FIG. 2 (color online). v2andv3as a function of centrality for the 5% most central collisions compared to calculations of the spatial eccentricities,"^Wnf2gand"^CGCn f2g. The eccentricities have been scaled to match the 2%–3% data usingk1 andk2.

10 20 30 40 50 60 70 80

nv

0 0.05 0.1

(a)

| > 1}

{2, | v2

| > 1}

{2, | v3

| > 1}

{2, | v4

3{4}

v

3/ RP

v

2 3/ 2

v 100

centrality percentile

0 10 20 30 40 50 60 70 80

n/nv

0 0.1 0.2 0.3 0.4

(b)

CGC{2}

/2

| > 1}

{2, | v2

CGC{2}

/3

| > 1}

{2, | v3

W{2}

/2

| > 1}

{2, | v2

{2}

W

/3

| > 1}

{2, | v3

FIG. 1 (color online). (a)v2,v3, andv4integrated over thept

range0:2< pt<5:0 GeV=cas a function of event centrality, with the more central (peripheral) collisions shown on the left- (right-)hand side, respectively. Full and open squares showv3f2g andv3f4g, respectively. In addition we showv²₃₌₂ andv3=RP, which represent the triangular flow measured relative to the second order event plane and the reaction plane, respectively (for the definitions, see text). (b) v2f2;jj>1g and v3f2;jj>1gdivided by the corresponding eccentricity versus centrality percentile for Glauber [22] and MC-KLN CGC [28]

initial conditions.

magnitude ofv2ðp_tÞis better described by=s¼0while for v3ðp_tÞ =s¼0:08 provides a better description. We anticipate future comparisons utilizing MC-KLN initial conditions.

For central collisions 0%–5% we observe that atp_t 2 GeV=c v3becomes equal tov2and atpt3 GeV=c v4

also reaches the same magnitude asv2 andv3. For more central collisions 0%–2%, we observe that v3 becomes equal to v2 at lower pt and reaches significantly larger

values than v2 at higher p_t. The same is true for v4

compared tov2.

We compare the structures found with azimuthal corre- lations between triggered and associated particles to those described by the measured v_n components. The two- particle azimuthal correlations are measured by calculating

CðÞ Nmixed

Nsame

dNsame=d

dNmixed=d; (3)

where¼trigassoc.dNsame=d(dNmixed=d) is the number of associated particles as function of within the same (different) event, and Nsame (Nmixed) the total number of associated particles in dNsame=d (dNmixed=d). Figure4shows the azimuthal correlation observed in very central collisions 0%–1%, for trigger particles in the range 2< p_t<3 GeV=cwith associated particles in 1< p_t<2 GeV=cfor pairs injj>1. We observe a clear doubly peaked correlation structure cen- tered opposite to the trigger particle. This feature has been observed at lower energies in broader centrality bins [32,33], but only after subtraction of the elliptic flow component. This two-peak structure has been interpreted as an indication for various jet-medium modifications (i.e., Mach cones) [32,33] and more recently as a manifes- tation of triangular flow [10–13]. We therefore compare the azimuthal correlation shape expected fromv2,v3,v4, and v5evaluated at corresponding transverse momenta with the measured two-particle azimuthal triggered correlation and find that the combination of these harmonics gives a natu- ral description of the observed correlation structure on the away side.

(rad) φ

∆

-1 0 1 2 3 4

)φ∆C(

0.992 0.994 0.996 0.998 1 1.002 1.004 1.006 1.008 1.01

< 3.0

t,trig

2.0 < p

< 2.0

t,assoc

1.0 < p

| < 0.8 η Centrality 0%-1%, |

| > 1 η

∆

|

| > 1}

η

∆ {2, |

2,3,4,5

v

FIG. 4 (color online). The two-particle azimuthal correlation, measured in 0< < and shown symmetrized over 2, between a trigger particle with2< pt<3 GeV=cand an asso- ciated particle with1< pt<2 GeV=cfor the 0%–1% centrality class. The solid red line shows the sum of the measured aniso- tropic flow Fourier coefficientsv2,v3,v4, andv5(dashed lines).

1 2 3 4 5

nv

0 0.1 0.2 0.3

(a)

Centrality 30%-40%

2{2}

v 3{2}

v 4{2}

v 5{2}

v /s = 0.0) 2 ( v

/s = 0.08) 2 ( v

/s = 0.0) 3 ( v

/s = 0.08) 3 ( v

1 2 3 4 5

nv

0 0.05 0.1

Centrality 0%-5% (b)

2{2}

v 3{2}

v 4{2}

v 5{2}

v

) c (GeV/

pt

0 1 2 3 4 5

nv

0 0.05

0.1 Centrality 0%-2% (c)

2{2}

v

3{2}

v

4{2}

v

5{2}

v

FIG. 3 (color online). v2,v3,v4,v5as a function of transverse momentum and for three event centralities. The full and open symbols are for >0:2and >1:0, respectively. (a) 30%–

40% compared to hydrodynamic model calculations, (b) 0%–5%

centrality percentile, (c) 0%–2% centrality percentile.

In summary, we have presented the first measurement at the LHC of triangularv3, quadrangularv4, and pentagonal particle flow v5. We have shown that the triangular flow and its fluctuations can be understood from the initial spatial anisotropy. The transverse momentum dependence ofv2andv3compared to model calculations favors a small value of the shear viscosity to entropy ratio =s. For the 5% most central collisions we have shown that v2 rises strongly with centrality in 1% centrality percentiles. The strong change in v2 and the small change in v3 as a function of centrality in these 1% centrality percentile classes follow the centrality dependence of the correspond- ing spatial anisotropies. The two-particle azimuthal corre- lation for the 0%–1% centrality class exhibits a double peak structure around(the ‘‘away side’’) without the subtraction of elliptic flow. We have shown that the measured anisotropic flow Fourier coefficients give a natu- ral description of this structure.

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: Calouste Gulbenkian Foundation from Lisbon 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 Amparoa`

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;

Hungarian OTKA and National Oce 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) of 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 HELEN Program (High-Energy physics Latin-American–

European 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 Scientic Research—NASR (Autoritatea Nat¸ionala˘ pentru Cercetare S¸tiint¸ica˘—ANCS); Federal Agency of Science of the Ministry of Education and Science of Russian Federation, International Science and Technology Center, Russian Academy of Sciences, Russian Federal Agency of Atomic Energy, Russian Federal Agency for Science and Innovations, and CERN- INTAS; Ministry of Education of Slovakia; CIEMAT, EELA, Ministerio de Educacio´n y Ciencia of Spain, Xunta de Galicia (Consellerı´a de Educacio´n), CEADEN, Cubaenergı´a, Cuba, and IAEA (International Atomic Energy Agency); The Ministry of Science and Technology and the National Research Foundation (NRF), South Africa; Swedish Reseach Council (VR) and Knut and Alice Wallenberg Foundation (KAW);

Ukraine Ministry of Education and Science; United Kingdom Science and Technology Facilities Council (STFC); The U.S. Department of Energy, the U.S.

National Science Foundation, the State of Texas, and the State of Ohio.

[1] J. Y. Ollitrault,Phys. Rev. D46, 229 (1992).

[2] S. Voloshin and Y. Zhang,Z. Phys. C70, 665 (1996).

[3] A. M. Poskanzer and S. A. Voloshin, Phys. Rev. C 58, 1671 (1998).

[4] S. A. Voloshin, A. M. Poskanzer, and R. Snellings, in Relativistic Heavy Ion Physics, Landolt-Bornstein Vol. 1 (Springer-Verlag, Berlin, 2010), pp. 5–54.

[5] K. Aamodtet al.(ALICE Collaboration),Phys. Rev. Lett.

105, 252302 (2010).

[6] S. Manly et al. (PHOBOS Collaboration), Nucl. Phys.

A774, 523 (2006).

[7] A. P. Mishra, R. K. Mohapatra, P. S. Saumia, and A. M.

Srivastava,Phys. Rev. C77, 064902 (2008).

[8] A. P. Mishra, R. K. Mohapatra, P. S. Saumia, and A. M.

Srivastava,Phys. Rev. C81, 034903 (2010).

[9] J. Takahashiet al.,Phys. Rev. Lett.103, 242301 (2009).

[10] B. Alver and G. Roland,Phys. Rev. C81, 054905 (2010);

82, 039903(E) (2010).

[11] B. H. Alver, C. Gombeaud, M. Luzum, and J. Y. Ollitrault, Phys. Rev. C82, 034913 (2010).

[12] D. Teaney and L. Yan,arXiv:1010.1876[Phys. Rev. C (to be published)].

[13] M. Luzum,Phys. Lett. B696, 499 (2011).

[14] K. H. Ackermannet al.(STAR Collaboration),Phys. Rev.

Lett.86, 402 (2001).

[15] S. S. Adler et al. (PHENIX Collaboration), Phys. Rev.

Lett.91, 182301 (2003).

[16] P. K. Kovtun, D. T. Son, and A. O. Starinets, Phys. Rev.

Lett.94, 111601 (2005).

[17] G.-Y. Qin, H. Petersen, S. A. Bass, and B. Muller,Phys.

Rev. C82, 064903 (2010).

[18] ALICE Collaboration,JINST3, S08002 (2008).

[19] ALICE Collaboration,J. Phys. G30, 1517 (2004).

[20] ALICE Collaboration,J. Phys. G32, 1295 (2006).

[21] K. Aamodtet al.(ALICE Collaboration),Phys. Rev. Lett.

106, 032301 (2011).

[22] M. L. Miller, K. Reygers, S. J. Sanders, and P. Steinberg, Annu. Rev. Nucl. Part. Sci.57, 205 (2007).

[23] A. Bilandzic, R. Snellings, and S. Voloshin,Phys. Rev. C 83, 044913 (2011).

[24] M. Gyulassy and X.-N. Wang,Comput. Phys. Commun.

83, 307 (1994); X. N. Wang and M. Gyulassy,Phys. Rev.

D44, 3501 (1991).

[25] R. Brun et al., CERN Program Library Long Write-up, W5013,GEANTDetector Description and Simulation Tool, 1994.

[26] N. Borghini, P. M. Dinh, and J. Y. Ollitrault,Phys. Rev. C 64, 054901 (2001).

[27] M. Miller and R. Snellings,arXiv:nucl-ex/0312008.

[28] H.-J. Drescher and Y. Nara, Phys. Rev. C 76, 041903 (2007).

[29] R. S. Bhalerao, M. Luzum, and J. Y. Ollitrault, arXiv:1104.4740.

[30] J. L. Nagle and M. P. McCumber,Phys. Rev. C83, 044908 (2011).

[31] B. Schenke, S. Jeon, and C. Gale,arXiv:1102.0575.

[32] A. Adareet al.(PHENIX Collaboration),Phys. Rev. C78, 014901 (2008).

[33] M. M. Aggarwalet al.(STAR Collaboration),Phys. Rev.

C82, 024912 (2010).

K. Aamodt,¹B. Abelev,²A. Abrahantes Quintana,³D. Adamova´,⁴A. M. Adare,⁵M. M. Aggarwal,⁶ G. Aglieri Rinella,⁷A. G. Agocs,⁸A. Agostinelli,⁹S. Aguilar Salazar,¹⁰Z. Ahammed,¹¹N. Ahmad,¹² A. Ahmad Masoodi,¹²S. U. Ahn,^13,14A. Akindinov,¹⁵D. Aleksandrov,¹⁶B. Alessandro,¹⁷R. Alfaro Molina,¹⁰ A. Alici,^9,7,18A. Alkin,¹⁹E. Almara´z Avin˜a,¹⁰T. Alt,²⁰V. Altini,^21,7I. Altsybeev,²²C. Andrei,²³A. Andronic,²⁴

V. Anguelov,^20,25C. Anson,²⁶T. Anticˇic´,²⁷F. Antinori,²⁸P. Antonioli,²⁹L. Aphecetche,³⁰H. Appelsha¨user,³¹ N. Arbor,³²S. Arcelli,⁹A. Arend,³¹N. Armesto,³³R. Arnaldi,¹⁷T. Aronsson,⁵I. C. Arsene,²⁴M. Arslandok,³¹

A. Asryan,²²A. Augustinus,⁷R. Averbeck,²⁴T. C. Awes,³⁴J. A¨ ysto¨,³⁵M. D. Azmi,¹²M. Bach,²⁰A. Badala`,³⁶ Y. W. Baek,^13,14R. Bailhache,³¹R. Bala,¹⁷R. Baldini Ferroli,¹⁸A. Baldisseri,³⁷A. Baldit,¹³J. Ba´n,³⁸R. C. Baral,³⁹

R. Barbera,⁴⁰F. Barile,²¹G. G. Barnafo¨ldi,⁸L. S. Barnby,⁴¹V. Barret,¹³J. Bartke,⁴²M. Basile,⁹N. Bastid,¹³ B. Bathen,⁴³G. Batigne,³⁰B. Batyunya,⁴⁴C. Baumann,³¹I. G. Bearden,⁴⁵H. Beck,³¹I. Belikov,⁴⁶F. Bellini,⁹ R. Bellwied,^47,48E. Belmont-Moreno,¹⁰S. Beole,⁴⁹I. Berceanu,²³A. Bercuci,²³E. Berdermann,²⁴Y. Berdnikov,⁵⁰

C. Bergmann,⁴³L. Betev,⁷A. Bhasin,⁵¹A. K. Bhati,⁶L. Bianchi,⁴⁹N. Bianchi,⁵²C. Bianchin,⁵³J. Bielcˇı´k,⁵⁴ J. Bielcˇı´kova´,⁴A. Bilandzic,⁵⁵E. Biolcati,^7,49F. Blanco,⁴⁸F. Blanco,⁵⁶D. Blau,¹⁶C. Blume,³¹M. Boccioli,⁷ N. Bock,²⁶A. Bogdanov,⁵⁷H. Bøggild,⁴⁵M. Bogolyubsky,⁵⁸L. Boldizsa´r,⁸M. Bombara,^41,59C. Bombonati,⁵³ J. Book,³¹H. Borel,³⁷A. Borissov,⁴⁷C. Bortolin,⁵³S. Bose,⁶⁰F. Bossu´,^7,49M. Botje,⁵⁵S. Bo¨ttger,⁶¹B. Boyer,⁶² P. Braun-Munzinger,²⁴L. Bravina,⁶³M. Bregant,³⁰T. Breitner,⁶¹M. Broz,⁶⁴R. Brun,⁷E. Bruna,⁵G. E. Bruno,²¹ D. Budnikov,⁶⁵H. Buesching,³¹S. Bufalino,⁴⁹K. Bugaiev,¹⁹O. Busch,²⁵Z. Buthelezi,⁶⁶D. Caffarri,⁵³X. Cai,⁶⁷ H. Caines,⁵E. Calvo Villar,⁶⁸P. Camerini,⁶⁹V. Canoa Roman,^70,71G. Cara Romeo,²⁹F. Carena,⁷W. Carena,⁷

N. Carlin Filho,⁷²F. Carminati,⁷A. Casanova Dı´az,⁵²M. Caselle,⁷J. Castillo Castellanos,³⁷

J. F. Castillo Hernandez,²⁴V. Catanescu,²³C. Cavicchioli,⁷J. Cepila,⁵⁴P. Cerello,¹⁷B. Chang,^35,73S. Chapeland,⁷ J. L. Charvet,³⁷S. Chattopadhyay,⁶⁰S. Chattopadhyay,¹¹M. Cherney,⁷⁴C. Cheshkov,^7,75B. Cheynis,⁷⁵ V. Chibante Barroso,⁷D. D. Chinellato,⁷⁶P. Chochula,⁷M. Chojnacki,⁷⁷P. Christakoglou,⁷⁷C. H. Christensen,⁴⁵ P. Christiansen,⁷⁸T. Chujo,⁷⁹C. Cicalo,⁸⁰L. Cifarelli,^9,7F. Cindolo,²⁹J. Cleymans,⁶⁶F. Coccetti,¹⁸J.-P. Coffin,⁴⁶

G. Conesa Balbastre,³²Z. Conesa del Valle,^7,46P. Constantin,²⁵G. Contin,⁶⁹J. G. Contreras,⁷⁰T. M. Cormier,⁴⁷ Y. Corrales Morales,⁴⁹P. Cortese,⁸¹I. Corte´s Maldonado,⁷¹M. R. Cosentino,⁷⁶F. Costa,⁷M. E. Cotallo,⁵⁶ E. Crescio,⁷⁰P. Crochet,¹³E. Cuautle,⁸²L. Cunqueiro,⁵²A. Dainese,^53,28H. H. Dalsgaard,⁴⁵A. Danu,⁸³I. Das,⁶⁰

D. Das,⁶⁰S. Dash,¹⁷A. Dash,³⁹S. De,¹¹A. De Azevedo Moregula,⁵²G. O. V. de Barros,⁷²A. De Caro,⁸⁴ G. de Cataldo,⁸⁵J. de Cuveland,²⁰A. De Falco,⁸⁶D. De Gruttola,⁸⁴H. Delagrange,³⁰E. Del Castillo Sanchez,⁷ Y. Delgado Mercado,⁶⁸G. Dellacasa,⁸¹A. Deloff,⁸⁷V. Demanov,⁶⁵N. De Marco,¹⁷E. De´nes,⁸S. De Pasquale,⁸⁴

A. Deppman,⁷²G. D. Erasmo,²¹R. de Rooij,⁷⁷D. Di Bari,²¹T. Dietel,⁴³C. Di Giglio,²¹S. Di Liberto,⁸⁸ A. Di Mauro,⁷P. Di Nezza,⁵²R. Divia`,⁷Ø. Djuvsland,¹A. Dobrin,^47,78T. Dobrowolski,⁸⁷I. Domı´nguez,⁸² B. Do¨nigus,²⁴O. Dordic,⁶³O. Driga,³⁰A. K. Dubey,¹¹L. Ducroux,⁷⁵P. Dupieux,¹³M. R. Dutta Majumdar,¹¹ A. K. Dutta Majumdar,⁶⁰D. Elia,⁸⁵D. Emschermann,⁴³H. Engel,⁶¹H. A. Erdal,⁸⁹B. Espagnon,⁶²M. Estienne,³⁰

S. Esumi,⁷⁹D. Evans,⁴¹S. Evrard,⁷G. Eyyubova,⁶³C. W. Fabjan,⁹⁰D. Fabris,^53,28J. Faivre,³²D. Falchieri,⁹ A. Fantoni,⁵²M. Fasel,²⁴R. Fearick,⁶⁶A. Fedunov,⁴⁴D. Fehlker,¹V. Fekete,⁶⁴D. Felea,⁸³G. Feofilov,²² A. Ferna´ndez Te´llez,⁷¹R. Ferretti,^81,7A. Ferretti,⁴⁹M. A. S. Figueredo,⁷²S. Filchagin,⁶⁵R. Fini,⁸⁵D. Finogeev,⁹¹ F. M. Fionda,²¹E. M. Fiore,²¹M. Floris,⁷S. Foertsch,⁶⁶P. Foka,²⁴S. Fokin,¹⁶E. Fragiacomo,⁹²M. Fragkiadakis,⁹³

U. Frankenfeld,²⁴U. Fuchs,⁷F. Furano,⁷C. Furget,³²M. Fusco Girard,⁸⁴J. J. Gaardhøje,⁴⁵S. Gadrat,³² M. Gagliardi,⁴⁹A. Gago,⁶⁸M. Gallio,⁴⁹D. R. Gangadharan,²⁶P. Ganoti,³⁴C. Garabatos,²⁴E. Garcia-Solis,⁹⁴

R. Gemme,⁸¹J. Gerhard,²⁰M. Germain,³⁰C. Geuna,³⁷M. Gheata,⁷A. Gheata,⁷B. Ghidini,²¹P. Ghosh,¹¹ P. Gianotti,⁵²M. R. Girard,⁹⁵P. Giubellino,^7,49E. Gladysz-Dziadus,⁴²P. Gla¨ssel,²⁵R. Gomez,⁹⁶E. G. Ferreiro,³³ L. H. Gonza´lez-Trueba,¹⁰P. Gonza´lez-Zamora,⁵⁶S. Gorbunov,²⁰S. Gotovac,⁹⁷V. Grabski,¹⁰L. K. Graczykowski,⁹⁵ R. Grajcarek,²⁵A. Grelli,⁷⁷C. Grigoras,⁷A. Grigoras,⁷V. Grigoriev,⁵⁷S. Grigoryan,⁴⁴A. Grigoryan,⁹⁸B. Grinyov,¹⁹ N. Grion,⁹²P. Gros,⁷⁸J. F. Grosse-Oetringhaus,⁷J.-Y. Grossiord,⁷⁵F. Guber,⁹¹R. Guernane,³²C. Guerra Gutierrez,⁶⁸ B. Guerzoni,⁹M. Guilbaud,⁷⁵K. Gulbrandsen,⁴⁵H. Gulkanyan,⁹⁸T. Gunji,⁹⁹R. Gupta,⁵¹A. Gupta,⁵¹H. Gutbrod,²⁴

Ø. Haaland,¹C. Hadjidakis,⁶²M. Haiduc,⁸³H. Hamagaki,⁹⁹G. Hamar,⁸B. H. Han,¹⁰⁰L. D. Hanratty,⁴¹ Z. Harmanova,⁵⁹J. W. Harris,⁵M. Hartig,³¹D. Hasegan,⁸³D. Hatzifotiadou,²⁹A. Hayrapetyan,^7,98M. Heide,⁴³

M. Heinz,⁵H. Helstrup,⁸⁹A. Herghelegiu,²³G. Herrera Corral,⁷⁰N. Herrmann,²⁵K. F. Hetland,⁸⁹B. Hicks,⁵ P. T. Hille,⁵B. Hippolyte,⁴⁶T. Horaguchi,⁷⁹Y. Hori,⁹⁹P. Hristov,⁷I. Hrˇivna´cˇova´,⁶²M. Huang,¹S. Huber,²⁴ T. J. Humanic,²⁶D. S. Hwang,¹⁰⁰R. Ilkaev,⁶⁵I. Ilkiv,⁸⁷M. Inaba,⁷⁹E. Incani,⁸⁶G. M. Innocenti,⁴⁹M. Ippolitov,¹⁶

M. Irfan,¹²C. Ivan,²⁴V. Ivanov,⁵⁰A. Ivanov,²²M. Ivanov,²⁴A. Jachołkowski,⁷P. M. Jacobs,¹⁰¹L. Jancurova´,⁴⁴ S. Jangal,⁴⁶M. A. Janik,⁹⁵R. Janik,⁶⁴P. H. S. Y. Jayarathna,^47,48S. Jena,¹⁰²L. Jirden,⁷G. T. Jones,⁴¹P. G. Jones,⁴¹

P. Jovanovic´,⁴¹W. Jung,¹⁴H. Jung,¹⁴A. Jusko,⁴¹A. B. Kaidalov,¹⁵S. Kalcher,²⁰P. Kalinˇa´k,³⁸M. Kalisky,⁴³ T. Kalliokoski,³⁵A. Kalweit,¹⁰³R. Kamermans,⁷⁷K. Kanaki,¹J. H. Kang,⁷³E. Kang,¹⁴V. Kaplin,⁵⁷ A. Karasu Uysal,^7,104O. Karavichev,⁹¹T. Karavicheva,⁹¹E. Karpechev,⁹¹A. Kazantsev,¹⁶U. Kebschull,⁶¹ R. Keidel,¹⁰⁵M. M. Khan,¹²P. Khan,⁶⁰A. Khanzadeev,⁵⁰Y. Kharlov,⁵⁸B. Kileng,⁸⁹S. Kim,¹⁰⁰B. Kim,⁷³ D. J. Kim,³⁵S. H. Kim,¹⁴D. S. Kim,¹⁴D. W. Kim,¹⁴J. H. Kim,¹⁰⁰J. S. Kim,¹⁴M. Kim,⁷³S. Kirsch,^20,7I. Kisel,²⁰

S. Kiselev,¹⁵A. Kisiel,⁷J. L. Klay,¹⁰⁶J. Klein,²⁵C. Klein-Bo¨sing,⁴³M. Kliemant,³¹A. Kluge,⁷M. L. Knichel,²⁴ K. Koch,²⁵M. K. Ko¨hler,²⁴A. Kolojvari,²²V. Kondratiev,²²N. Kondratyeva,⁵⁷A. Konevskih,⁹¹E. Kornas´,⁴²

C. Kottachchi Kankanamge Don,⁴⁷R. Kour,⁴¹M. Kowalski,⁴²S. Kox,³²G. Koyithatta Meethaleveedu,¹⁰² K. Kozlov,¹⁶J. Kral,³⁵I. Kra´lik,³⁸F. Kramer,³¹I. Kraus,²⁴T. Krawutschke,^25,107M. Kretz,²⁰M. Krivda,^41,38 F. Krizek,³⁵M. Krus,⁵⁴E. Kryshen,⁵⁰M. Krzewicki,⁵⁵Y. Kucheriaev,¹⁶C. Kuhn,⁴⁶P. G. Kuijer,⁵⁵P. Kurashvili,⁸⁷ A. Kurepin,⁹¹A. B. Kurepin,⁹¹A. Kuryakin,⁶⁵S. Kushpil,⁴V. Kushpil,⁴H. Kvaerno,⁶³M. J. Kweon,²⁵Y. Kwon,⁷³

P. Ladro´n de Guevara,^56,82V. Lafage,⁶²I. Lakomov,²²C. Lara,⁶¹A. Lardeux,³⁰P. La Rocca,⁴⁰D. T. Larsen,¹ C. Lazzeroni,⁴¹R. Lea,⁶⁹Y. Le Bornec,⁶²K. S. Lee,¹⁴S. C. Lee,¹⁴F. Lefe`vre,³⁰J. Lehnert,³¹L. Leistam,⁷ M. Lenhardt,³⁰V. Lenti,⁸⁵H. Leo´n,¹⁰I. Leo´n Monzo´n,⁹⁶H. Leo´n Vargas,³¹P. Le´vai,⁸X. Li,¹⁰⁸J. Lien,¹R. Lietava,⁴¹ S. Lindal,⁶³V. Lindenstruth,²⁰C. Lippmann,^24,7M. A. Lisa,²⁶L. Liu,¹P. I. Loenne,¹V. R. Loggins,⁴⁷V. Loginov,⁵⁷

S. Lohn,⁷D. Lohner,²⁵C. Loizides,¹⁰¹K. K. Loo,³⁵X. Lopez,¹³M. Lo´pez Noriega,⁶²E. Lo´pez Torres,³ G. Løvhøiden,⁶³X.-G. Lu,²⁵P. Luettig,³¹M. Lunardon,⁵³G. Luparello,⁴⁹L. Luquin,³⁰C. Luzzi,⁷K. Ma,⁶⁷R. Ma,⁵

D. M. Madagodahettige-Don,⁴⁸A. Maevskaya,⁹¹M. Mager,^103,7D. P. Mahapatra,³⁹A. Maire,⁴⁶M. Malaev,⁵⁰ I. Maldonado Cervantes,⁸²D. Mal’Kevich,¹⁵P. Malzacher,²⁴A. Mamonov,⁶⁵L. Mangotra,⁵¹V. Manko,¹⁶ F. Manso,¹³V. Manzari,⁸⁵Y. Mao,^32,67M. Marchisone,^13,49J. Maresˇ,¹⁰⁹G. V. Margagliotti,^69,92A. Margotti,²⁹

A. Marı´n,²⁴C. Markert,¹¹⁰I. Martashvili,¹¹¹P. Martinengo,⁷M. I. Martı´nez,⁷¹A. Martı´nez Davalos,¹⁰ G. Martı´nez Garcı´a,³⁰Y. Martynov,¹⁹A. Mas,³⁰S. Masciocchi,²⁴M. Masera,⁴⁹A. Masoni,⁸⁰L. Massacrier,⁷⁵ M. Mastromarco,⁸⁵A. Mastroserio,⁷Z. L. Matthews,⁴¹A. Matyja,^42,30D. Mayani,⁸²M. A. Mazzoni,⁸⁸F. Meddi,¹¹² A. Menchaca-Rocha,¹⁰P. Mendez Lorenzo,⁷J. Mercado Pe´rez,²⁵M. Meres,⁶⁴Y. Miake,⁷⁹J. Midori,¹¹³L. Milano,⁴⁹ J. Milosevic,⁶³A. Mischke,⁷⁷D. Mis´kowiec,^24,7C. Mitu,⁸³J. Mlynarz,⁴⁷B. Mohanty,¹¹A. K. Mohanty,⁷L. Molnar,⁷

L. Montan˜o Zetina,⁷⁰M. Monteno,¹⁷E. Montes,⁵⁶M. Morando,⁵³D. A. Moreira De Godoy,⁷²S. Moretto,⁵³ A. Morsch,⁷V. Muccifora,⁵²E. Mudnic,⁹⁷S. Muhuri,¹¹H. Mu¨ller,⁷M. G. Munhoz,⁷²L. Musa,⁷A. Musso,¹⁷ J. L. Nagle,⁴⁵B. K. Nandi,¹⁰²R. Nania,²⁹E. Nappi,⁸⁵C. Nattrass,¹¹¹F. Navach,²¹S. Navin,⁴¹T. K. Nayak,¹¹ S. Nazarenko,⁶⁵G. Nazarov,⁶⁵A. Nedosekin,¹⁵M. Nicassio,²¹B. S. Nielsen,⁴⁵T. Niida,⁷⁹S. Nikolaev,¹⁶ V. Nikolic,²⁷S. Nikulin,¹⁶V. Nikulin,⁵⁰B. S. Nilsen,⁷⁴M. S. Nilsson,⁶³F. Noferini,²⁹G. Nooren,⁷⁷N. Novitzky,³⁵ A. Nyanin,¹⁶A. Nyatha,¹⁰²C. Nygaard,⁴⁵J. Nystrand,¹H. Obayashi,¹¹³A. Ochirov,²²H. Oeschler,^103,7S. K. Oh,¹⁴

J. Oleniacz,⁹⁵C. Oppedisano,¹⁷A. Ortiz Velasquez,⁸²G. Ortona,^7,49A. Oskarsson,⁷⁸P. Ostrowski,⁹⁵ J. Otwinowski,²⁴K. Oyama,²⁵K. Ozawa,⁹⁹Y. Pachmayer,²⁵M. Pachr,⁵⁴F. Padilla,⁴⁹P. Pagano,^7,84G. Paic´,⁸²

F. Painke,²⁰C. Pajares,³³S. K. Pal,¹¹S. Pal,³⁷A. Palaha,⁴¹A. Palmeri,³⁶G. S. Pappalardo,³⁶W. J. Park,²⁴ B. Pastircˇa´k,³⁸D. I. Patalakha,⁵⁸V. Paticchio,⁸⁵A. Pavlinov,⁴⁷T. Pawlak,⁹⁵T. Peitzmann,⁷⁷D. Peresunko,¹⁶ C. E. Pe´rez Lara,⁵⁵D. Perini,⁷W. Peryt,⁹⁵A. Pesci,²⁹V. Peskov,^7,82Y. Pestov,¹¹⁴A. J. Peters,⁷V. Petra´cˇek,⁵⁴

M. Petran,⁵⁴M. Petris,²³P. Petrov,⁴¹M. Petrovici,²³C. Petta,⁴⁰S. Piano,⁹²A. Piccotti,¹⁷M. Pikna,⁶⁴P. Pillot,³⁰ O. Pinazza,⁷L. Pinsky,⁴⁸N. Pitz,³¹D. B. Piyarathna,^47,48R. Platt,⁴¹M. Płoskon´,¹⁰¹J. Pluta,⁹⁵T. Pocheptsov,^44,63

S. Pochybova,⁸P. L. M. Podesta-Lerma,⁹⁶M. G. Poghosyan,⁴⁹K. Pola´k,¹⁰⁹B. Polichtchouk,⁵⁸A. Pop,²³ V. Pospı´sˇil,⁵⁴B. Potukuchi,⁵¹S. K. Prasad,⁴⁷R. Preghenella,¹⁸F. Prino,¹⁷C. A. Pruneau,⁴⁷I. Pshenichnov,⁹¹ G. Puddu,⁸⁶A. Pulvirenti,^40,7V. Punin,⁶⁵M. Putisˇ,⁵⁹J. Putschke,⁵H. Qvigstad,⁶³A. Rachevski,⁹²A. Rademakers,⁷ S. Radomski,²⁵T. S. Ra¨iha¨,³⁵J. Rak,³⁵A. Rakotozafindrabe,³⁷L. Ramello,⁸¹A. Ramı´rez Reyes,⁷⁰M. Rammler,⁴³

R. Raniwala,¹¹⁵S. Raniwala,¹¹⁵S. S. Ra¨sa¨nen,³⁵D. Rathee,⁶K. F. Read,¹¹¹J. S. Real,³²K. Redlich,^87,116 P. Reichelt,³¹M. Reicher,⁷⁷R. Renfordt,³¹A. R. Reolon,⁵²A. Reshetin,⁹¹F. Rettig,²⁰J.-P. Revol,⁷K. Reygers,²⁵

H. Ricaud,¹⁰³L. Riccati,¹⁷R. A. Ricci,¹¹⁷M. Richter,^1,63P. Riedler,⁷W. Riegler,⁷F. Riggi,^40,36 M. Rodrı´guez Cahuantzi,⁷¹D. Rohr,²⁰D. Ro¨hrich,¹R. Romita,²⁴F. Ronchetti,⁵²P. Rosinsky´,⁷P. Rosnet,¹³ S. Rossegger,⁷A. Rossi,⁵³F. Roukoutakis,⁹³S. Rousseau,⁶²P. Roy,⁶⁰C. Roy,⁴⁶A. J. Rubio Montero,⁵⁶R. Rui,⁶⁹

E. Ryabinkin,¹⁶A. Rybicki,⁴²S. Sadovsky,⁵⁸K. Sˇafarˇı´k,⁷R. Sahoo,⁵³P. K. Sahu,³⁹P. Saiz,⁷H. Sakaguchi,¹¹³ S. Sakai,¹⁰¹D. Sakata,⁷⁹C. A. Salgado,³³S. Sambyal,⁵¹V. Samsonov,⁵⁰X. Sanchez Castro,⁸²L. Sˇa´ndor,³⁸ A. Sandoval,¹⁰S. Sano,⁹⁹M. Sano,⁷⁹R. Santo,⁴³R. Santoro,⁸⁵J. Sarkamo,³⁵P. Saturnini,¹³E. Scapparone,²⁹ F. Scarlassara,⁵³R. P. Scharenberg,¹¹⁸C. Schiaua,²³R. Schicker,²⁵C. Schmidt,²⁴H. R. Schmidt,^24,119S. Schreiner,⁷ S. Schuchmann,³¹J. Schukraft,⁷Y. Schutz,^7,30K. Schwarz,²⁴K. Schweda,²⁵G. Scioli,⁹E. Scomparin,¹⁷R. Scott,¹¹¹ P. A. Scott,⁴¹G. Segato,⁵³I. Selyuzhenkov,²⁴S. Senyukov,⁸¹S. Serci,⁸⁶E. Serradilla,⁵⁶A. Sevcenco,⁸³I. Sgura,⁸⁵ G. Shabratova,⁴⁴R. Shahoyan,⁷S. Sharma,⁵¹N. Sharma,⁶K. Shigaki,¹¹³M. Shimomura,⁷⁹K. Shtejer,³Y. Sibiriak,¹⁶

M. Siciliano,⁴⁹E. Sicking,⁷T. Siemiarczuk,⁸⁷D. Silvermyr,³⁴G. Simonetti,^21,7R. Singaraju,¹¹R. Singh,⁵¹ S. Singha,¹¹T. Sinha,⁶⁰B. C. Sinha,¹¹B. Sitar,⁶⁴M. Sitta,⁸¹T. B. Skaali,⁶³K. Skjerdal,¹R. Smakal,⁵⁴N. Smirnov,⁵

R. Snellings,^55,77C. Søgaard,⁴⁵R. Soltz,²H. Son,¹⁰⁰M. Song,⁷³J. Song,¹²⁰C. Soos,⁷F. Soramel,⁵³ M. Spyropoulou-Stassinaki,⁹³B. K. Srivastava,¹¹⁸J. Stachel,²⁵I. Stan,⁸³G. Stefanek,⁸⁷T. Steinbeck,²⁰ M. Steinpreis,²⁶E. Stenlund,⁷⁸G. Steyn,⁶⁶D. Stocco,³⁰C. H. Stokkevag,¹M. Stolpovskiy,⁵⁸P. Strmen,⁶⁴ A. A. P. Suaide,⁷²M. A. Subieta Va´squez,⁴⁹T. Sugitate,¹¹³C. Suire,⁶²M. Sukhorukov,⁶⁵M. Sˇumbera,⁴T. Susa,²⁷

T. J. M. Symons,¹⁰¹A. Szanto de Toledo,⁷²I. Szarka,⁶⁴A. Szostak,¹C. Tagridis,⁹³J. Takahashi,⁷⁶ J. D. Tapia Takaki,⁶²A. Tauro,⁷G. Tejeda Mun˜oz,⁷¹A. Telesca,⁷C. Terrevoli,²¹J. Tha¨der,²⁴D. Thomas,⁷⁷ J. H. Thomas,²⁴R. Tieulent,⁷⁵A. R. Timmins,^47,48D. Tlusty,⁵⁴A. Toia,⁷H. Torii,¹¹³L. Toscano,¹⁷T. Traczyk,⁹⁵

D. Truesdale,²⁶W. H. Trzaska,³⁵T. Tsuji,⁹⁹A. Tumkin,⁶⁵R. Turrisi,²⁸A. J. Turvey,⁷⁴T. S. Tveter,⁶³J. Ulery,³¹ K. Ullaland,¹A. Uras,^86,75J. Urba´n,⁵⁹G. M. Urciuoli,⁸⁸G. L. Usai,⁸⁶M. Vajzer,⁵⁴M. Vala,^44,38 L. Valencia Palomo,⁶²S. Vallero,²⁵N. van der Kolk,⁵⁵P. Vande Vyvre,⁷M. van Leeuwen,⁷⁷L. Vannucci,¹¹⁷

A. Vargas,⁷¹R. Varma,¹⁰²M. Vasileiou,⁹³A. Vasiliev,¹⁶V. Vechernin,²²M. Veldhoen,⁷⁷M. Venaruzzo,⁶⁹ E. Vercellin,⁴⁹S. Vergara,⁷¹D. C. Vernekohl,⁴³R. Vernet,¹²¹M. Verweij,⁷⁷L. Vickovic,⁹⁷G. Viesti,⁵³ O. Vikhlyantsev,⁶⁵Z. Vilakazi,⁶⁶O. Villalobos Baillie,⁴¹Y. Vinogradov,⁶⁵A. Vinogradov,¹⁶L. Vinogradov,²² T. Virgili,⁸⁴Y. P. Viyogi,¹¹A. Vodopyanov,⁴⁴K. Voloshin,¹⁵S. Voloshin,⁴⁷G. Volpe,²¹B. von Haller,⁷D. Vranic,²⁴

G. Øvrebekk,¹J. Vrla´kova´,⁵⁹B. Vulpescu,¹³A. Vyushin,⁶⁵B. Wagner,¹V. Wagner,⁵⁴R. Wan,^46,67Y. Wang,²⁵ Y. Wang,⁶⁷M. Wang,⁶⁷D. Wang,⁶⁷K. Watanabe,⁷⁹J. P. Wessels,^7,43U. Westerhoff,⁴³J. Wiechula,^25,119J. Wikne,⁶³

M. Wilde,⁴³A. Wilk,⁴³G. Wilk,⁸⁷M. C. S. Williams,²⁹B. Windelband,²⁵L. Xaplanteris Karampatsos,¹¹⁰ H. Yang,^25,37 S. Yasnopolskiy,¹⁶J. Yi,¹²⁰Z. Yin,⁶⁷H. Yokoyama,⁷⁹I.-K. Yoo,¹²⁰J. Yoon,⁷³X. Yuan,⁶⁷ I. Yushmanov,¹⁶E. Zabrodin,⁶³C. Zach,⁵⁴C. Zampolli,⁷S. Zaporozhets,⁴⁴A. Zarochentsev,²²P. Za´vada,¹⁰⁹ N. Zaviyalov,⁶⁵H. Zbroszczyk,⁹⁵P. Zelnicek,^7,61A. Zenin,⁵⁸I. Zgura,⁸³M. Zhalov,⁵⁰X. Zhang,^13,67D. Zhou,⁶⁷

F. Zhou,⁶⁷Y. Zhou,⁷⁷X. Zhu,⁶⁷A. Zichichi,^9,18G. Zinovjev,¹⁹Y. Zoccarato,⁷⁵and M. Zynovyev¹⁹ (ALICE Collaboration)

1Department of Physics and Technology, University of Bergen, Bergen, Norway

2Lawrence Livermore National Laboratory, Livermore, California, USA

3Centro de Aplicaciones Tecnolo´gicas y Desarrollo Nuclear (CEADEN), Havana, Cuba

4Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Rˇ ezˇ u Prahy, Czech Republic

5Yale University, New Haven, Connecticut, USA

6Physics Department, Panjab University, Chandigarh, India

7European Organization for Nuclear Research (CERN), Geneva, Switzerland

8KFKI Research Institute for Particle and Nuclear Physics, Hungarian Academy of Sciences, Budapest, Hungary

9Dipartimento di Fisica dell’Universita` and Sezione INFN, Bologna, Italy