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

Abstract

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

4 pages, 4 figures