The X(3872) puzzle: insights from its radiative decays
Published on:
July 20, 2026
Abstract
The internal structure of the $X(3872)$ is still a highly debated topic in heavy-quarkonium physics. Here, we investigate its radiative transitions, specifically $X(3872)\to J/\psi\,\gamma$ and $X(3872)\to \psi^\prime\gamma$, assuming a compact tetraquark configuration. The decay amplitudes are evaluated within a non-relativistic approach, relying on the initial tetraquark wave function. To model this state, we apply the Born--Oppenheimer approximation, separating the dynamics of the slow heavy charm quarks from the fast light quarks. By variationally determining the effective Born--Oppenheimer potential, we solve the Schr\"odinger equation for the $c\bar c$ subsystem. Our theoretical prediction for the ratio of the radiative branching fractions is $\mathcal{R}_{\mathrm{th}} = 1.4 \pm 0.3$, which nicely matches recent LHCb data. More broadly, this technique successfully maps out the mass spectrum of compact $c\bar c q\bar q$ configurations, demonstrating the effectiveness of the Born--Oppenheimer method for exploring exotic hadron structures.
DOI: https://doi.org/10.22323/1.525.0052
How to cite
Metadata are provided both in
article format (very
similar to INSPIRE)
as this helps creating very compact bibliographies which
can be beneficial to authors and readers, and in
proceeding format which
is more detailed and complete.