Probing QCD matter via $K^{*0}(892)$ and $\phi(1020)$ resonance production at RHIC

Abstract

We present the measurements of invariant yields of $K^{*0}$ and $\phi$ resonances at midrapidity in Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7 - 200 GeV using the STAR detector. The transverse momentum ($p_{T}$) spectra and $p_{T}$-integrated yields of $K^{*0}$ and $\phi$ have been studied. The ratios between resonance ($K^{*0}$ and $\phi$) to non-resonance particles ($K$) are presented as a function of centrality. It is found that $K^{*0}/K^{-}$ ratios are suppressed in the most central collisions as compared to peripheral ones for all studied collision energies. On the other hand, $\phi/K^{-}$ ratios are weakly depend on centrality. These results can be understood by considering the effect of more hadronic rescattering for $K^{*0}$ (lifetime $\sim$ 4 fm/c) as compared to $\phi$ (lifetime $\sim$ 42 fm/c). We have also presented the measurement of the first-order azimuthal anisotropy (known as directed flow, $v_{1}$) of $\phi$ meson as a function of rapidity ($y$) at midrapidity in Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7 - 200 GeV. The slope of $\phi$-meson $v_{1}$ ($dv_{1}/dy$) has been compared to the $dv_{1}/dy$ of other identified particles. We have found that all particles that consist of produced quarks show similar behaviour for $\sqrt{s_{NN}}$ $>$ 14.5 GeV.