$K^{*0}$ production in Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 7.7, 11.5, 14.5, 19.6, 27 and 39 GeV from RHIC beam energy scan

TL;DR

This paper measures $K^{*0}$ meson production in Au+Au collisions across a range of energies at RHIC, revealing insights into hadronic re-scattering effects and medium properties in heavy-ion collisions.

Contribution

First comprehensive measurement of $K^{*0}$ production at multiple RHIC BES energies, analyzing yield ratios and medium effects in heavy-ion collisions.

Findings

$K^{*0}/K$ ratios are smaller in heavy-ion than in small systems.

The ratios decrease with collision centrality, indicating medium effects.

Data supports hadronic re-scattering dominance over regeneration.

Abstract

We report the measurement of $K^{*0}$ meson at midrapidity ($|y|<$ 1.0) in Au+Au collisions at $\sqrt{s_{\rm NN}}$~=~7.7, 11.5, 14.5, 19.6, 27 and 39 GeV collected by the STAR experiment during the RHIC beam energy scan (BES) program. The transverse momentum spectra, yield, and average transverse momentum of $K^{*0}$ are presented as functions of collision centrality and beam energy. The $K^{*0}/K$ yield ratios are presented for different collision centrality intervals and beam energies. The $K^{*0}/K$ ratio in heavy-ion collisions are observed to be smaller than that in small system collisions (e+e and p+p). The $K^{*0}/K$ ratio follows a similar centrality dependence to that observed in previous RHIC and LHC measurements. The data favor the scenario of the dominance of hadronic re-scattering over regeneration for $K^{*0}$ production in the hadronic phase of the medium.