Origin of the mass splitting of elliptic anisotropy in a multiphase transport model

Abstract

The mass splitting of elliptic anisotropy ($v_2$) at low transverse momentum is considered as a hallmark of hydrodynamic collective flow. We investigate a multiphase transport (AMPT) model where the $v_2$ is mainly generated by an anisotropic escape mechanism, not of the hydrodynamic flow nature, and where mass splitting is also observed. We demonstrate that the $v_2$ mass splitting in AMPT is small right after hadronization (especially when resonance decays are included); the mass splitting mainly comes from hadronic rescatterings, even though their contribution to the overall charged hadron $v_2$ is small. These findings are qualitatively the same as those from hybrid models that combine hydrodynamics with a hadron cascade. We further show that there is no qualitative difference between heavy ion collisions and small system collisions. Our results indicate that the $v_2$ mass splitting is not a unique signature of hydrodynamic collective flow and thus cannot distinguish whether the elliptic flow is generated mainly from hydrodynamics or the anisotropic parton escape.

5 pages, 4 figures

References in corpus (9)

• Systematic Measurements of Identified Particle Spectra in pp, d+Au and Au+Au Collisions from STAR
• Observation of long-range near-side angular correlations in proton-lead collisions at the LHC
• Correlations from hydrodynamic flow in p-Pb collisions
• Elliptic and triangular flow in p+Pb and peripheral Pb+Pb collisions from parton scatterings
• Anisotropic parton escape is the dominant source of azimuthal anisotropy in transport models
• Mass ordering of differential elliptic flow and its violation for phi mesons
• Evolution of transverse flow and effective temperatures in the parton phase from a multi-phase transport model
• Elliptic flow in proton-proton collisions at 7 TeV
• Directed and elliptic flow in heavy ion collisions from $E_{\mathrm{beam}}=90$ MeV/nucleon to $E_{c.m.}=200$ GeV/nucleon

Cited by in corpus (14)

• Experimental overview on small collision systems at the LHC
• Further developments of a multi-phase transport model for relativistic nuclear collisions
• Importance of isobar density distributions on the chiral magnetic effect search
• Varying the chiral magnetic effect relative to flow in a single nucleus-nucleus collision
• Isolating the chiral magnetic effect from backgrounds by pair invariant mass
• Measurements of mass-dependent azimuthal anisotropy in central $p$$+$Au, $d$$+$Au, and ${}^3$He$+$Au collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV
• Origin of the mass splitting of azimuthal anisotropies in a multi-phase transport model
• Charm quarks are more hydrodynamic than light quarks in final-state elliptic flow
• Investigating the NCQ scaling of elliptic flow at LHC with a multiphase transport model
• Collectivity in large and small systems formed in ultrarelativistic collisions
• Particle productions and anisotropic flows from the AMPT model for Cu+Au collisions at $\sqrt{s_{NN}}=200$ GeV
• Disentangling the development of collective flow in high energy proton proton collisions with a multiphase transport model
• Collective flow and hydrodynamics in large and small systems at the LHC
• Particle species dependence of elliptic flow fluctuations in Pb-Pb collisions at LHC energies in a multiphase transport model