Productions of $\eta$, $\rho^0$ and $\phi$ at large transverse momentum   in Heavy ion Collisions
  The suppression of the productions of the $\eta$ meson in relativistic heavy-ion collisions and its ratio of $\eta/\pi^0$ are computed theoretically in the framework of the perturbative QCD(pQCD) to confront the experimental data which matches well. We explore how the hadron production ratios as$\eta/\pi^0$ would further disclose the informations of the production suppressions due to the energy loss of the energetic jet that propagating though the QGP medium. Also, we present our further studies on vector mesons such as $\rho^0$ and $\phi$ within the same framework. The theoretical predictions based on pQCD are thus firstly given which give a decent description on the experimental measurements. It paved the way to the uniformly understanding of the strong suppression of single hadron productions at large transverse momentum which is a convincing evidence of the jet quenching effect. 
Wei Dai and Ben-Wei Zhang
hep-ph nucl-th