Light scalar $K_{0}^{*}(700)$ meson in vacuum and a hot medium

TL;DR

This study investigates the properties of the light scalar $K_{0}^{*}(700)$ meson in vacuum and hot medium using a quark-antiquark model, analyzing its mass and coupling dependence on temperature and observing its melting near the critical temperature.

Contribution

It provides a temperature-dependent analysis of the $K_{0}^{*}(700)$ meson’s mass and coupling, incorporating medium effects and aligning zero-temperature results with experimental data.

Findings

Mass remains stable up to 0.6 T_c, then decreases towards zero near T_c.

Coupling increases rapidly after 0.85 T_c.

Zero-temperature mass agrees with PDG average Breit-Wigner value.

Abstract

The $K_{0}^{*}(700)$ meson appears as the lightest strange scalar meson in PDG. Although there were a lot of experimental and theoretical efforts to establish this particle and determine its properties and nature, it still needs confirmation in an experiment and its internal quark-gluon organization needs to be clarified. In this connection, we study some spectroscopic properties of this state in a hot medium as well as a vacuum by modeling it as a usual meson of a quark and an aniquark. In particular, we investigate its mass and coupling or decay constant in terms of the temperature of a hot medium by including the medium effects by the fermionic and gluonic parts of the energy momentum tensor as well as the temperature-dependent continuum threshold, quark, gluon and mixed condensates. We observe that the mass of $K_{0}^{*}(700)$ remains unchanged up to $T \simeq 0.6 ~ T_c$ with $ T_c $ being the critical temperature, but it starts to diminish after this point and approaches zero near to the critical temperature referring to the melting of the meson. The coupling of $K_{0}^{*}(700)$ is also sensitive to $ T $ at higher temperatures. It starts to grow rapidly after $T \simeq 0.85 ~ T_c$. We turn off the medium effects and calculate the mass and coupling of the $K_{0}^{*}(700)$ state at zero temperature. The obtained mass is in accord with the average Breit-Wigner mass value reported by PDG.