The $X(3872)\rightarrow J/\psi \pi \gamma$ and $X(3872)\rightarrow J/\psi \pi\pi \gamma$ decays

TL;DR

This paper analyzes the decay mechanisms of the X(3872) particle into J/psi, pions, and photons, highlighting the dominant meson contributions and potential for experimental measurement of decay rates.

Contribution

It provides a detailed theoretical study of the radiative decay channels of X(3872), identifying dominant meson contributions and estimating branching ratios relevant for experiments.

Findings

X(3872) decay to J/psi pi gamma is dominated by omega meson.

Branching ratios are approximately 8.10e-3 and 2.38% for the two decay modes.

Decays can help extract couplings revealing the isoscalar and isovector components of X(3872).

Abstract

We study the $\rho$ and $\omega$ meson contribution to the radiative decays $X(3872)\rightarrow J/\psi \pi \gamma$ and $X(3872)\rightarrow J/\psi \pi\pi \gamma$. The $X(3872)\rightarrow J/\psi \pi \gamma$ is dominated by the $\omega$ meson. As for the $X(3872)\rightarrow J/\psi \pi\pi \gamma$, the contributions of the cascade decays through the $\rho$ and $\omega$ mesons are strongly suppressed with respect to the diagrams which proceed either through the $\psi(2S)$ or the three body decay of $\rho$. The branching ratios of $X(3872)\rightarrow J/\psi \pi \gamma$ and $X(3872)\rightarrow J/\psi \pi\pi \gamma$ are $(8.10^{+3.50}_{-2.88})\times10^{-3}$ and $(2.38\pm1.06)\%$, which may be accessible by the BESIII and LHCb Collaborations. Especailly, the $X(3872)\rightarrow J/\psi \pi \gamma$ and $X(3872)\rightarrow J/\psi \pi^+\pi^- \gamma$ decays can be employed to extract the couplings $g_{X\psi\omega}$ and $g_{X\psi\rho}$, which probe the isoscalar and isovector components of the X(3872) wave function respectively.