Elliptic flow of hadrons in equal-velocity quark combination mechanism in relativistic heavy-ion collisions

Abstract

We apply a quark combination model with equal-velocity combination (EVC) approximation to study the elliptic flow (v_{2}) of hadrons in heavy-ion collisions in a wide collision energy range (sqrt{s_{NN}}= 27–5020 GeV). Utilizing the simple relationship between v_{2} of hadrons and those of quarks under EVC, we find that v_{2} of up/down quarks obtained by experimental data of proton is consistent with that obtained by data of varLambda and varXi . v_{2} of strange quarks obtained by data of varOmega is consistent with that obtained by data of varLambda and varXi , and at RHIC energies it is also consistent with that obtained by data of phi . This means that v_{2} of these hadrons have a common quark-level source. Using data of D^0, we obtain v_{2} of charm quarks with p_Tlesssim 6 GeV/c. We find that under EVC charm quark dominates v_{2} of D mesons at low p_{T} but light-flavor quarks significantly contribute to v_{2} of D mesons in the range 3lesssim p_{T}lesssim 8 GeV/c. We predict v_{2} of charmed baryons varLambda _{c}^{+} and varXi _{c}^{0} which show a significant enhancement at intermediate p_{T} due to the double contribution of light-flavor quarks. The properties of the obtained quark v_{2} under EVC are studied and a regularity for v_{2} of quarks as the function of p_{T}/m is found.