Elliptic flow of identified hadrons in Pb-Pb collisions at TeV
Abstract
The elliptic flow coefficient ( v 2) of identified particles in Pb-Pb collisions at TeV was measured with the ALICE detector at the Large Hadron Collider (LHC). The results were obtained with the Scalar Product method, a two-particle correlation technique, using a pseudo-rapidity gap of |Δ η| > 0 .9 between the identified hadron under study and the reference particles. The v 2 is reported for π ±, K±, K{S/0}, , ϕ, , and in several collision centralities. In the low transverse momentum ( p T) region, p T < 3 GeV/ c, v 2( p 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 π ± and the combined K± and K{S/0} results, are described fairly well by hydrodynamic calculations coupled to a hadronic cascade model (VISHNU) for central collisions. However, the same calculations fail to reproduce the v 2( p T) for , ϕ, and . For transverse momentum values larger than about 3 GeV/ c, particles tend to group according to their type, i.e. mesons and baryons. The present measurements exhibit deviations from the number of constituent quark (NCQ) scaling at the level of ±20% for p T > 3 GeV/ c. [Figure not available: see fulltext.]
- Publication:
-
Journal of High Energy Physics
- Pub Date:
- June 2015
- DOI:
- 10.1007/JHEP06(2015)190
- Bibcode:
- 2015JHEP...06..190A
- Keywords:
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- Collective flow;
- Heavy Ions;
- Particle correlations and fluctuations