Low mass enhanced probability of pion in hadronic matter due to its Landau cut contributions

TL;DR

This paper investigates how Landau cut contributions in the medium modify the pion spectral function, leading to enhanced low-mass probability that could explain low-mass dilepton enhancement in hot and dense hadronic matter.

Contribution

It provides a detailed analysis of Landau cut effects on the pion spectral function at finite temperature and density using real-time thermal field theory, highlighting their role in low-mass dilepton production.

Findings

Landau cut contributions significantly affect the pion spectral function.

Enhanced low-mass probability in pion spectral function observed.

Implications for low-mass dilepton enhancement in heavy-ion collisions.

Abstract

In the real-time thermal field theory, the pion self-energy at finite temperature and density is evaluated where the different mesonic and baryonic loops are considered. The interactions of pion with the other mesons and baryons in the medium are governed by the effective hadronic Lagrangian densities whose effective strength of coupling constants have been determined from the experimental decay widths of the mesons and baryons. The detail branch cut structures of these different mesonic and baryonic loops are analyzed. The Landau cut contributions of different baryon and meson loops become only relevant around the pion pole and it is completely appeared in presence of medium. The in-medium spectral function of pion has been plotted for different values of temperature, baryon chemical potential as well as three momentum of the pion. A noticeable low mass probability in pion spectral function promise to contribute in the low mass dilepton enhancement via indirect modification of $\rho$ self-energy for $\pi\pi$ loop.