A novel spectral broadening from vector--axial-vector mixing in dense matter

TL;DR

This paper investigates how baryonic matter induces mixing between vector and axial-vector mesons, leading to spectral broadening that could impact dilepton measurements in dense environments.

Contribution

It introduces a new mechanism of spectral broadening caused by vector-axial-vector mixing in dense matter, with implications for interpreting experimental data.

Findings

Enhanced vector spectral function below $ ho$ meson mass

Spectral broadening at small three-momenta

Potential relevance to dilepton measurements

Abstract

The presence of baryonic matter leads to the mixing between transverse $\rho$ and $a_1$ mesons through a set of $\omega\rho a_1$-type interactions, which results in the modification to the dispersion relation. We show that a clear enhancement of the vector spectral function appears below $\sqrt{s}=m_\rho$ for small three-momenta of the $\rho$ meson, and thus the vector spectrum exhibits broadening. We also discuss its relevance to dilepton measurements.