K*0 production in Cu+Cu and Au+Au collisions at \sqrt{s_NN} = 62.4 GeV and 200 GeV

TL;DR

This study measures K*0 meson production in Cu+Cu and Au+Au collisions at different energies, analyzing spectra, ratios, and flow to understand the hadronic medium effects and particle production mechanisms.

Contribution

It provides new measurements of K*0 production and flow at RHIC energies, highlighting the dominance of re-scattering over regeneration in K*0 formation.

Findings

K*0 yields favor re-scattering over regeneration

Elliptic flow and RCP data support quark coalescence models

Energy and system size dependence of spectra and ratios

Abstract

We report on K*0 production at mid-rapidity in Au+Au and Cu+Cu collisions at \sqrt{s_{NN}} = 62.4 and 200 GeV collected by the Solenoid Tracker at RHIC (STAR) detector. The K*0 is reconstructed via the hadronic decays K*0 \to K+ pi- and \bar{K*0} \to K-pi+. Transverse momentum, pT, spectra are measured over a range of pT extending from 0.2 GeV/c to 5 GeV/c. The center of mass energy and system size dependence of the rapidity density, dN/dy, and the average transverse momentum, <pT>, are presented. The measured N(K*0)/N(K) and N(\phi)/N(K*0) ratios favor the dominance of re-scattering of decay daughters of K*0 over the hadronic regeneration for the K*0 production. In the intermediate pT region (2.0 < pT < 4.0 GeV/c), the elliptic flow parameter, v2, and the nuclear modification factor, RCP, agree with the expectations from the quark coalescence model of particle production.