$K^{\ast 0}$ meson production using a transport and a statistical hadronization model at energies covered by the RHIC beam energy scan

Abstract

In this paper, we discuss the centrality and energy dependence of $K^{\ast 0}$ resonance production using ultrarelativistic quantum molecular dynamics (UrQMD) and thermal models. The $K^{\ast 0}/K$ ratios obtained from the UrQMD and thermal models are compared with measurements done by the STAR experiment in Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7, 11.5, 14.5, 19.6, 27, and 39 GeV. The $K^{\ast 0}/K$ ratio from the thermal model is consistent with data in most-peripheral collisions, however it overpredicts the ratio in central Au+Au collisions. This could be due to the fact that the thermal model does not have a hadronic rescattering phase, which is expected to be dominant in more central collisions. Furthermore, we have studied the $K^{\ast 0}/K$ ratio from UrQMD by varying the hadron propagation time ($\tau$) within the range 5 to 50 fm/c. It was found that the $K^{\ast 0}/K$ ratio decreases with increasing $\tau$. Comparison between data and UrQMD suggest, one needs to consider a $\tau$ $\approx$ 10-50 fm/c to explain data at $\sqrt{s_{NN}}$ = 7.7-39 GeV in Au+Au collisions. We also predict the rapidity distribution of $K^{\ast 0}$ from UrQMD which could be measured in the STAR beam energy scan phase II (BES-II) program.

Comments: 10 pages, 8 figures