Disclosing $D^*\bar{D}^*$ molecular states in the $B_c^- \to \pi^- J/\psi \omega$ decay

TL;DR

This paper investigates the molecular nature of the $X(3940)$ and $X(3930)$ resonances by analyzing the decay processes $B_c^- o \pi^- J/\psi \omega$ and $B_c^- o \pi^- D^*ar{D}^*$, predicting observable features like a cusp at the $D^*ar{D}^*$ threshold.

Contribution

It demonstrates the molecular nature of the $X(3940)$ and $X(3930)$ resonances through decay analysis and predicts distinctive experimental signatures.

Findings

A cusp with large strength at the $D^*ar{D}^*$ threshold in the $J/\psi\omega$ mass distribution.

Predicted ratio of strengths between the cusp peak and the $D^*ar{D}^*$ distribution maximum.

Evidence supporting the molecular composition of the resonances.

Abstract

We study the $B_c^- \to \pi^- J/\psi \omega$ and $B_c^- \to \pi^- D^* \bar{D}^*$ reactions and show that they are related by the presence of two resonances, the $X(3940)$ and $X(3930)$, that are of molecular nature and couple most strongly to $D^* \bar{D}^*$, but also to $J/\psi\omega$. Because of that, in the $J/\psi\omega$ mass distribution we find a cusp with large strength at the $D^* \bar{D}^*$ threshold and predict the ratio of strengths between the peak of the cusp and the maximum of the $D^* \bar{D}^*$ distribution close to $D^* \bar{D}^*$ threshold, which are distinct features of the molecular nature of these two resonances.