$X(3872)$ production and absorption in a hot hadron gas

TL;DR

This paper models the evolution of the $X(3872)$ particle in a hot hadron gas, showing that its abundance decreases significantly due to interactions, with implications for understanding its production in heavy ion collisions.

Contribution

It introduces new interaction cross sections for $X(3872)$ involving anomalous couplings, significantly increasing previous estimates and refining its predicted abundance.

Findings

$X(3872)$ abundance reduces by a factor of 4 during hadronic phase

New cross sections are larger due to anomalous coupling diagrams

Impacts interpretation of $X(3872)$ production in heavy ion collisions

Abstract

We calculate the time evolution of the $X(3872)$ abundance in the hot hadron gas produced in the late stage of heavy ion collisions. We use effective field Lagrangians to obtain the production and dissociation cross sections of $X(3872)$. In this evaluation we include diagrams involving the anomalous couplings $\pi D^*\bar{D}^*$ and $X \bar{D}^{\ast} D^{\ast}$ and also the couplings of the $X(3872)$ with charged $D$ and $D^*$ mesons. With these new terms the $X(3872)$ interaction cross sections are much larger than those found in previous works. Using these cross sections as input in rate equations, we conclude that during the expansion and cooling of the hadronic gas, the number of $X(3872)$, originally produced at the end of the mixed QGP/hadron gas phase, is reduced by a factor of 4.