# The $ρ$ meson in hot hadron matter and low mass dilepton spectra

The structure of the one loop self-energy graphs of the $\rho$ meson is analyzed in the real time formulation of thermal field theory. The modified spectral function of the $\rho$ meson in hot hadronic matter leads to a large enhancement of lepton pair production below the bare peak of the $\rho$. It has been shown that the effective temperature extracted from the inverse slope of the transverse momentum distributions for various invariant mass ($M$) windows of the pair can be used as an efficient tool to characterize different phases of the evolving matter.

**Comments:**Presented at the 6th International Conference on the Physics and Astrophysics of Quark Gluon Plasma, ICPAQGP2010, Dec. 6-10, Goa, India

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