Elliptic flow of identified hadrons in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV
B. Abelev
,
Laurent Aphecetche
(1)
,
Guillaume Batigne
(1)
,
I. Belikov
(2)
,
C. Cheshkov
(3)
,
B. Cheynis
(3)
,
H. Delagrange
(1)
,
L. Ducroux
(3)
,
B. Erazmus
(1)
,
Magali Estienne
(1)
,
J.-Y. Grossiord
(3)
,
Maxime Guilbaud
(3)
,
A. Lardeux
(1)
,
A. Maire
(2)
,
Gines Martinez Garcia
(1)
,
J. Martin Blanco
(1)
,
A. Mas
(1)
,
L. Massacrier
(1)
,
L. Molnar
(2)
,
A. Morreale
(1)
,
Philippe Pillot
(1)
,
L. Ronflette
(1)
,
C. Roy
(2)
,
Y. Schutz
(1)
,
Alexandre Shabetai
(1)
,
Diego Stocco
(1)
,
R. Tieulent
(3)
,
A. Uras
(3)
,
R. Vernet
(4)
,
M. Wang
(1)
,
Y. Zoccarato
(3)
,
G. Conesa Balbastre
(5)
,
J. Faivre
(5)
,
C. Furget
(5)
,
R. Guernane
(5)
,
S. Kox
(5)
,
J.S. Real
(5)
,
C. Silvestre
(5)
,
Y.W. Baek
(6)
,
V. Barret
(6)
,
N. Bastid
(6)
,
A. Batista Camejo
(6)
,
P. Crochet
(6)
,
P. Dupieux
(6)
,
Marie Germain
(1)
,
S. Li
(6)
,
X. Lopez
(6)
,
F. Manso
(6)
,
M. Marchisone
(6)
,
S. Porteboeuf-Houssais
(6)
,
P. Rosnet
(6)
,
L. Valencia Palomo
(6)
,
B. Vulpescu
(6)
,
Z. Conesa Del Valle
(7)
,
I. Das
(7)
,
B. Espagnon
(7)
,
C. Hadjidakis
(7)
,
I. Lakomov
(7)
,
C. Suire
(7)
,
J. D. Tapia Takaki
(7)
1
SUBATECH -
Laboratoire SUBATECH Nantes
2 IPHC - Institut Pluridisciplinaire Hubert Curien
3 IPNL - Institut de Physique Nucléaire de Lyon
4 CC-IN2P3 - Centre de Calcul de l'IN2P3
5 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
6 LPC - Laboratoire de Physique Corpusculaire - Clermont-Ferrand
7 IPNO - Institut de Physique Nucléaire d'Orsay
2 IPHC - Institut Pluridisciplinaire Hubert Curien
3 IPNL - Institut de Physique Nucléaire de Lyon
4 CC-IN2P3 - Centre de Calcul de l'IN2P3
5 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
6 LPC - Laboratoire de Physique Corpusculaire - Clermont-Ferrand
7 IPNO - Institut de Physique Nucléaire d'Orsay
B. Abelev
- Function : Author
Laurent Aphecetche
- Function : Author
- PersonId : 2010
- IdHAL : laurent-aphecetche
- ORCID : 0000-0001-7662-3878
- IdRef : 113847653
Guillaume Batigne
- Function : Author
- PersonId : 175820
- IdHAL : guillaume-batigne
- ORCID : 0000-0001-8638-6300
- IdRef : 077207874
B. Cheynis
- Function : Author
- PersonId : 750577
- IdHAL : brigitte-cheynis
- IdRef : 032215606
Magali Estienne
- Function : Author
- PersonId : 179790
- IdHAL : magali-estienne
- ORCID : 0000-0003-0687-5580
Maxime Guilbaud
- Function : Author
- PersonId : 177174
- IdHAL : maxime-guilbaud
- ORCID : 0000-0001-5990-482X
- IdRef : 236157566
Gines Martinez Garcia
- Function : Author
- PersonId : 169952
- IdHAL : gines-martinez
- ORCID : 0000-0002-8657-6742
- IdRef : 068952961
Philippe Pillot
- Function : Author
- PersonId : 175815
- IdHAL : ppillot
- ORCID : 0000-0002-9067-0803
C. Roy
- Function : Author
- PersonId : 742351
- IdHAL : christelle-roy
- ORCID : 0000-0001-5920-6271
Alexandre Shabetai
- Function : Author
- PersonId : 181202
- IdHAL : alexandre-shabetai
- ORCID : 0000-0003-3069-726X
Diego Stocco
- Function : Author
- PersonId : 170966
- IdHAL : diego-stocco
- ORCID : 0000-0002-5377-5163
- IdRef : 204479150
G. Conesa Balbastre
- Function : Author
- PersonId : 737477
- IdHAL : conesa-balbastre-gustavo
- ORCID : 0000-0001-5283-3520
J.S. Real
- Function : Author
- PersonId : 737490
- IdHAL : jean-sebastien-real
- ORCID : 0000-0003-1584-783X
- IdRef : 156873133
Marie Germain
- Function : Author
- PersonId : 170960
- IdHAL : marie-germain
- ORCID : 0000-0001-7382-1609
- IdRef : 176579958
S. Porteboeuf-Houssais
- Function : Author
- PersonId : 1350722
- IdHAL : sarah-porteboeuf
- ORCID : 0000-0002-2646-6189
Abstract
The elliptic flow coefficient ($v_{2}$) of identified particles in Pb--Pb collisions at $\sqrt{s_\mathrm{{NN}}} = 2.76$ TeV was measured with the ALICE detector at the LHC. The results were obtained with the Scalar Product method, a two-particle correlation technique, using a pseudo-rapidity gap of $|\Delta\eta| > 0.9$ between the identified hadron under study and the reference particles. The $v_2$ is reported for $\pi^{\pm}$, $\mathrm{K}^{\pm}$, $\mathrm{K}^0_\mathrm{S}$, p+$\overline{\mathrm{p}}$, $\mathrm{\phi}$, $\Lambda$+$\overline{\mathrm{\Lambda}}$, $\Xi^-$+$\overline{\Xi}^+$ and $\Omega^-$+$\overline{\Omega}^+$ in several collision centralities. In the low transverse momentum ($p_{\mathrm{T}}$) region, $p_{\mathrm{T}} < 2 $GeV/$c$, $v_2(p_\mathrm{T})$ exhibits a particle mass dependence consistent with elliptic flow accompanied by the transverse radial expansion of the system with a common velocity field. The experimental data for $\pi^{\pm}$ and $\mathrm{K}$ are described fairly well by hydrodynamical calculations coupled to a hadronic cascade model (VISHNU) for central collisions. However, the same calculations fail to reproduce the $v_2(p_\mathrm{T})$ for p+$\overline{\mathrm{p}}$, $\mathrm{\phi}$, $\Lambda$+$\overline{\mathrm{\Lambda}}$ and $\Xi^-$+$\overline{\Xi}^+$. For transverse momentum values larger than about 3 GeV/$c$, particles tend to group according to their type, i.e. mesons and baryons. However, the experimental data at the LHC exhibit deviations from the number of constituent quark (NCQ) scaling at the level of $\pm$20$\%$ for $p_{\mathrm{T}} > 3 $GeV/$c$.