$\bar K^*$ meson in dense matter

TL;DR

This paper investigates the in-medium properties of the $ar K^*$ meson in nuclear matter, revealing an attractive potential and significantly increased width, and proposes an experimental method to observe these modifications.

Contribution

It provides a self-consistent theoretical analysis of $ar K^*$ meson behavior in dense matter, including decay channels and spectral functions, which is novel in the field.

Findings

$ar K^*$ experiences a moderately attractive potential at normal nuclear density.

The $ar K^*$ width increases fivefold in nuclear matter.

Proposes a feasible experimental reaction to detect in-medium modifications.

Abstract

We study the properties of $\bar K^*$ mesons in nuclear matter using a unitary approach in coupled channels within the framework of the local hidden gauge formalism and incorporating the $\bar K \pi$ decay channel in matter. The in-medium $\bar K^* N$ interaction accounts for Pauli blocking effects and incorporates the $\bar K^*$ self-energy in a self-consistent manner. We also obtain the $\bar K^*$ (off-shell) spectral function and analyze its behaviour at finite density and momentum. At normal nuclear matter density, the $\bar K^*$ meson feels a moderately attractive potential while the $\bar K^*$ width becomes five times larger than in free space. We estimate the transparency ratio of the $\gamma A \to K^+ K^{* -} A^\prime$ reaction, which we propose as a feasible scenario at present facilities to detect the changes of the properties of the $\bar K^*$ meson in the nuclear medium.