# QM 2011 - XXII International Conference on Ultrarelativistic Nucleus-Nucleus Collisions

May 22 – 28, 2011
Centre Bonlieu
Europe/Zurich timezone

## Measurement of light vector mesons by PHENIX experiment at RHIC

May 23, 2011, 6:50 PM
20m
Salon Haendel AB (Imperial Palace)

### Speaker

Dr Deepali Sharma (Weizmann Institute of Science)

### Description

The PHENIX experiment at RHIC has carried out systematic measurements of $\phi$ and $\omega$ mesons in $p+p$, $d+Au$, $Cu+Cu$ and $Au+Au$ collisions at $\sqrt{s_{NN}}$ = 200 GeV. Consistent results have been obtained using leptonic and hadronic decay modes as well as different analysis techniques. In $p+p$ collisions, the transverse momentum distributions of $\omega$ and $\phi$, as well as all other mesons measured by PHENIX, are well described by the Tsallis distribution functional form. Combining the $e^+e^-$ and hadronic ($\omega \rightarrow \pi^0 gamma,~\pi^0\pi^+\pi^-$, $\phi \rightarrow K^+K^-$) decay channels, $\omega$ and $\phi$ have been measured over a $p_T$ range of 0 - 13.5 GeV/c and 0 - 7 GeV/c respectively. New results obtained using hadronic and dielectron channels of $\omega$ and $\phi$ mesons in $d+Au$ collisions extend the $p_T$ coverage to 0.25 - 13 GeV/c and 0 - 7 GeV/c respectively, and reveal a moderate enhancement at intermediate $p_T$ and a hint of suppression at $p_T >$ 8 GeV/c. Both observations are consistent with previous results for $\pi^0$, $\pi^+ + \pi^-$, $K_s$ and $K^+ + K^-$. The nuclear modification factor of $\omega$ in $Cu+Cu$ and $Au+Au$ collisions measured over a $p_T$ range of 4 - 12 GeV/c, shows that $\omega$ has a similar suppression pattern as that of $\pi^0$ and $\eta$, strengthening the observation that mesons with different masses have similar behavior but different from the one of baryons. However, $\phi$ in $Cu+Cu$ and $Au+Au$ collisions, measured from 1 - 7 GeV/c, shows a suppression, that is smaller than that of the $\pi^0$ and $\eta$ in the intermediate $p_T$ range (2 - 5 GeV/c), whereas at higher $p_T$, within the large experimental uncertainties, the amount of suppression appears similar to that of the light mesons. Results of $\phi$ production at $\sqrt{s_{NN}}$ = 62.4 GeV show a similar behavior but with larger uncertainties. This talk will review the most recent results obtained for light vector mesons in different collision systems and energies.

### Primary author

Dr Deepali Sharma (Weizmann Institute of Science)

 Slides