Light Vector Meson Properties

The light vector mesons $\rho$, $\omega$ and $\phi$ have been suggested as probes for a QGP, since their masses, widths and decay branching ratios may change in hot and dense matter. The $\phi$ meson with quark content $s\bar{s}$ is particularly interesting [13]. The main decay channel of this meson is $\phi\rightarrow K^+K^-$, and since the $\phi$ mass is only about 30 MeV above the mass of two kaons, the branching ratios are expected to change dramatically in a QGP, due to chiral symmetry restoration.

A comparison between the decays of $\phi\rightarrow K^+K^-$ and $\phi\rightarrow e^+e^-$ requires very high statistics, since the branch to the latter is only about 0.03 % and the signal is hard to distinguish from the combinatorial background.