Violation of mass ordering for multi-strange hadrons at RHIC and LHC

Abstract

We study effects of the hadronic rescattering on final observables especially for multi-strange hadrons such as $\phi$, $\Xi$ and $\Omega$ in high-energy heavy-ion collisions within an integrated dynamical approach. In this approach, (3+1)-dimensional ideal hydrodynamics is combined with a microscopic transport model, JAM. We simulate the collisions with or without hadronic rescatterings and compare observables between these two options so that we quantify the effects of the hadronic rescattering. We find that the mean transverse momentum and the elliptic flow parameter of multi-strange hadrons are less affected by hadronic rescattering and, as a result, the mass ordering of the $p_T$-differential elliptic flow parameter $v_2(p_T)$ is violated: At the RHIC and the LHC energies the $v_2(p_T)$ for $\phi$-mesons is larger than that for protons in the low-$p_T$ regions.