Centrality dependence of charged hadron and strange hadron elliptic flow from<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msqrt><mml:mrow><mml:msub><mml:mi>s</mml:mi><mml:mrow><mml:mi mathvariant="italic">NN</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:msqrt><mml:mo>=</mml:mo><mml:mn>200</mml:mn></mml:mrow></mml:math>GeV Au+Au collisions

We present STAR results on the elliptic flow ${v}_{2}$ of charged hadrons, strange and multistrange particles from $\sqrt{{s}_{\mathit{NN}}}=200$ GeV Au+Au collisions at the BNL Relativistic Heavy Ion Collider (RHIC). The detailed study of the centrality dependence of ${v}_{2}$ over a broad transverse momentum range is presented. Comparisons of different analysis methods are made in order to estimate systematic uncertainties. To discuss the nonflow effect, we have performed the first analysis of ${v}_{2}$ with the Lee-Yang zero method for ${K}_{S}^{0}$ and \ensuremath{\Lambda}. In the relatively low ${p}_{T}$ region, ${p}_{T}\ensuremath{\leqslant}2 \mathrm{GeV}/c$, a scaling with ${m}_{T}\ensuremath{-}m$ is observed for identified hadrons in each centrality bin studied. However, we do not observe ${v}_{2}({p}_{T})$ scaled by the participant eccentricity to be independent of centrality. At higher ${p}_{T},2\ensuremath{\leqslant}{p}_{T}\ensuremath{\leqslant}6 \mathrm{GeV}/c,{v}_{2}$ scales with quark number for all hadrons studied. For the multistrange hadron \ensuremath{\Omega}, which does not suffer appreciable hadronic interactions, the values of ${v}_{2}$ are consistent with both ${m}_{T}\ensuremath{-}m$ scaling at low ${p}_{T}$ and number-of-quark scaling at intermediate ${p}_{T}$. As a function of collision centrality, an increase of ${p}_{T}$-integrated ${v}_{2}$ scaled by the participant eccentricity has been observed, indicating a stronger collective flow in more central Au+Au collisions.

Перевод пока недоступен