The charming case of $X(3872)$ and $\chi_{c1}(2P)$

TL;DR

This paper investigates the nature of the $ ext{X}(3872)$ and $ ext{chi}_{c1}(2P)$ mesons through a theoretical analysis of their radiative decays, supporting the identification of $ ext{X}(3872)$ as $ ext{chi}_{c1}(2P)$ based on recent experimental data.

Contribution

It applies a heavy quark large mass limit framework to analyze electric dipole transitions, providing insights into the meson's structure and decay properties.

Findings

Results align with LHCb measurements for $ ext{X}(3872)$ as $ ext{chi}_{c1}(2P)$.

Supports the identification of $ ext{X}(3872)$ with $ ext{chi}_{c1}(2P)$.

Provides a theoretical basis for understanding radiative decays of heavy quarkonia.

Abstract

More than twenty years have elapsed since the discovery of $\chi_{c1}(3872)$ (previously denoted as $X(3872)$), and an impressive amount of theoretical and experimental studies has been devoted to its properties, decays and production mechanisms. Despite the extensive work, a full understanding of the nature of $\chi_{c1}(3872)$ is still missing. In the present study we reconsider a theoretical framework based on the heavy quark large mass limit to analyse the radiative decays of heavy quarkonia, in particular the electric dipole transitions of $\chi_{c1}(2P)$ to S-wave charmonia. The results favourably compare to recent measurements for $\chi_{c1}(3872)$, obtained by the LHCb Collaboration, if this meson is identified with $\chi_{c1}(2P)$.