Radiative Transitions of Charmoniumlike Exotics in the Dynamical Diquark Model

TL;DR

This paper uses the dynamical diquark model to calculate radiative decay widths of charmoniumlike exotics, testing their shared substructure hypothesis and comparing results with molecular models.

Contribution

It provides new calculations of radiative decay widths for exotic states using the dynamical diquark model, offering insights into their internal structure.

Findings

Decay widths of 100-1000 keV support common substructure hypothesis.

Magnetic-dipole decay width for Zc(4020)^0 to gamma X(3872) is less than 10 keV.

Results differ from molecular model predictions.

Abstract

Using the dynamical diquark model, we calculate the electric-dipole radiative decay widths to $X(3872)$ of the lightest negative-parity exotic candidates, including the four $I=0$, $J^{PC} \! = \! 1^{--}$ ("$Y$") states. The $O$(100--1000 keV) values obtained test the hypothesis of a common substructure shared by all of these states. We also calculate the magnetic-dipole radiative decay width for $Z_c(4020)^0 \! \to \! \gamma X(3872)$, and find it to be rather smaller ($<$~10 keV) than its predicted value in molecular models.