Ellipticity of dilepton production from a hot and magnetized hadronic medium

Abstract

We study the azimuthal angle and transverse momentum dependence of dilepton production from hot and magnetized hadronic matter using $\rho^0$-meson dominance. The thermomagnetic spectral function of the $\rho^0$ is evaluated using the real time method of thermal field theory and Schwinger proper-time formulation. A continuous spectrum is obtained in which there is sizeable Landau cut contributions in the low invariant mass region as a consequence of finite background field. The emission rate of the dileptons is found to be significantly anisotropic in this region and the later effectively increases with the strength of the background field. In addition, we also evaluate the elliptic flow parameter ($v_2$) as a function of invariant mass for different values of magnetic field and temperature. We find that in low invariant mass region $v_2$ remains positive at lower values of $eB$ signifying that the production rate could be larger along the direction transverse to the background field. This behaviour is consistent with the angular dependence of dilepton production rate.