The effect of in-medium vector and axial-vector meson masses on photon production is studied. We assume that the effective mass of a vector meson in hot nuclear matter decreases according to a universal scaling law, while that of an axial-vector meson is given by Weinberg’s mass formula. We find that the thermal production rate of photons increases with reduced masses, and is enhanced by an order of magnitude at $T=160\mathrm{}\mathrm{MeV}$ with $m_{\rho }=300\mathrm{}\mathrm{MeV}.$ Assuming a hydrodynamic evolution, we estimate the effect of the reduced masses on photon production in nucleus-nucleus collisions. The result is compared to experimental data from the WA80/WA98 Collaboration.

• Received 23 February 1998

DOI:https://doi.org/10.1103/PhysRevC.58.1689