Eur. Phys. J. C 70, 251-262 (2010)
https://doi.org/10.1140/epjc/s10052-010-1446-8

Analytic structure of ρ meson propagator at finite temperature

¹ Variable Energy Cyclotron Centre, 1/AF, Bidhannagar, Kolkata, 700064, India
² Theory Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, 700064, India

mallik@theory.saha.ernet.in

Received: 1 June 2010
Revised: 27 July 2010
Published online: 23 October 2010

Abstract

We analyse the structure of one-loop self-energy graphs for the ρ meson in real time formulation of finite temperature field theory. We find the discontinuities of these graphs across the unitary and the Landau cuts. These contributions are identified with different sources of medium modification discussed in the literature. We also calculate numerically the imaginary and the real parts of the self-energies and construct the spectral function of the ρ meson, which are compared with an earlier determination. A significant contribution arises from the unitary cut of the π ω loop, that was ignored so far in the literature.