Properties of the phi meson at finite temperature

Abstract

We calculate the $\varphi$-meson propagator at finite temperature at the one--loop order. The real and imaginary parts are studied separately in full kinematic ranges. From this activity we investigate how temperature affects such things as decay widths and dispersion relations. {}From here we estimate the thermal rate of lepton pair radiation in a hadron gas proceeding through $K^{+}{K}^{-}\to \varphi \to {\ell }^{+}{\ell }^{-}$ and $\pi \rho \to \varphi \to {\ell }^{+}{\ell }^{-}$. We find several interesting things. From the dispersion relations we learn the effective mass calculated this way increases with temperature as does the partial width, but only slightly. At $T=200$ MeV, the mass increases by $\sim$ 4 MeV and the partial width increases by 34\%. Polarizations are indistinguishable for practical purposes.

Comments: 13 pages in ReVTeX 3.0, 11 uuencoded Postscript figures (enclosed), MSUCL-910, McGill 93/41