K(892)*resonance production in Au+Au andp+pcollisions atsNN=200GeV

Abstract

The short-lived K(892)* resonance provides an efficient tool to probe properties of the hot and dense medium produced in relativistic heavy-ion collisions. We report measurements of K* in {radical}(s{sub NN})=200 GeV Au+Au and p+p collisions reconstructed via its hadronic decay channels K(892)*{sup 0}{yields}K{pi} and K(892)*{sup {+-}}{yields}K{sub S}{sup 0}{pi}{sup {+-}} using the STAR detector at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. The K*{sup 0} mass has been studied as a function of p{sub T} in minimum bias p+p and central Au+Au collisions. The K* p{sub T} spectra for minimum bias p+p interactions and for Au+Au collisions in different centralities are presented. The K*/K yield ratios for all centralities in Au+Au collisions are found to be significantly lower than the ratio in minimum bias p+p collisions, indicating the importance of hadronic interactions between chemical and kinetic freeze-outs. A significant nonzero K*{sup 0} elliptic flow (v{sub 2}) is observed in Au+Au collisions and is compared to the K{sub S}{sup 0} and {lambda} v{sub 2}. The nuclear modification factor of K* at intermediate p{sub T} is similar to that of K{sub S}{sup 0} but different from {lambda}. This establishes a baryon-meson effect over a mass effect in the particle production atmore » intermediate p{sub T} (2<p{sub T}{<=}4 GeV/c)« less