Md. Nasim

Systematic investigation of partonic collectivity through centrality dependence of elliptic flow of multi-strange hadrons in Au + Au collisions at sNN=200 GeV in STAR

Abstract We present the measurement of centrality dependence of multi-strange hadrons ( Ω , Ξ and ϕ ) elliptic flow ( v 2 ) at mid-rapidity in Au + Au collision at s N N = 200 GeV .We investigate number-of-constituent quark (NCQ) scaling of identified hadrons v 2 for different collision centralities. Maximum deviation from ideal NCQ scaling is observed at the level of 10% for centrality 30–80% at ( m T − m 0 ) / n q > 0.6 GeV / c 2 . This may indicate smaller contribution to the collectivity from the partonic phase in the peripheral collisions. We also observe that the mass ordering of v 2 break down between proton and ϕ -meson for p T 1 GeV / c . This could be due to the effect of later stage hadronic interactions on v 2 .

Elliptic flow of φ mesons as a sensitive probe for the onset of the deconfinement transition in high energy heavy-ion collisions

Elliptic flow (v_2) of \phi-meson is shown to be a sensitive probe of the partonic collectivity using A Multi Phase Transport (AMPT) model. Within the ambit of the AMPT model with partonic interactions (string melting version), the \phi-meson v_2 at midrapidity is found to have negligible contribution from hadronic interactions for Au+Au collisions at 200 GeV per nucleon. Changing the hadron cascade time in the model calculations does not change the \phi-meson v_2, while it reduces the v_2 of proton at low transverse momentum (pT). These observations indicate that a substantial reduction in \phi-mesons v_2 as a function of colliding beam energy would suggest the dominance of hadronic interactions over partonic interactions.

Elliptic and triangular flow in asymmetric heavy-ion collisions

We present a study of the elliptic (v2) and triangular (v3) flow and their corresponding eccentricity fluctuations for asymmetric (Au+Ag, Au+Cu and Au+Si) collisions at \sqrt_NN = 200 GeV. These are compared to the corresponding results from symmetric (Au+Au and Cu+Cu) collisions at the same energy. The study which is carried out using a multi-phase transport (AMPT) model shows that triangularity (\epsilon_3), fluctuations in triangularity and v3 do not show much variation for the different colliding ion sizes studied. However the eccentricity (\epsilon_2), fluctuations in eccentricity and v2 shows a strong dependence on colliding ion size for a given number of participating nucleons. Our study thus indicates that asymmetric heavy-ion collisions could be used to constrain models dealing with flow fluctuations in heavy-ion collisions.

Measurements of DS±-meson production in Au + Au collisions at sNN=200 GeV in STAR

We present the first measurement of the nuclear modification factor

Insight from elliptic flow of open charm mesons using quark coalescence model at RHIC and LHC energies

R_{AA}

Understanding pseudorapidity dependence of elliptic flow in heavy-ion collisions using a transport model

and elliptic flow