Measurement of light vector mesons by PHENIX experiment at RHIC

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

Salon Haendel AB

Imperial Palace

Parallel Hadron thermodynamics and chemistry Hadron thermodynamics and chemistry


Dr Deepali Sharma (Weizmann Institute of Science)


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)

Presentation materials