Does the $J^{PC}=1^{+-}$ counterpart of the $X(3872)$ exist?

TL;DR

This study investigates the potential existence of a $J^{PC}=1^{+-}$ partner to the $X(3872)$ using a coupled-channels quark model, predicting possible states and decay patterns to guide experimental confirmation.

Contribution

It introduces a coupled-channels calculation within a constituent quark model to predict and analyze the $J^{PC}=1^{+-}$ partner of the $X(3872)$, including decay predictions.

Findings

Two states found near the $ ilde X(3872)$ signal region.

One state identified as a dressed $car c$ $2^1P_1$.

A bound state below the $Dar D^*$ threshold.

Abstract

We explore the possible existence of the $J^{PC}=1^{+-}$ counterpart of the $X(3872)$ state in a coupled-channels calculation within a constituent quark model, with the aim of confirming the existence of the so-called $\tilde{X}(3872)$ state observed by the COMPASS Collaboration. Two states are found in the energy region of the $\tilde X(3872)$ signal, both with almost equal mixture of $c\bar c$ $2^1P_1$ state and $D^*\bar D^{(*)}$ channels: One that can be identified as the dressed $c\bar c$ $2^1P_1$ and a bound state below the $D\bar D^*$ threshold. We provide predictions of strong and radiative decays that could help to clarify the existence of such structures.