Production of the spin-2 partner of $X(3872)$ in $e^+e^-$ collisions

Author:

Pan-Pan Shi, Vadim Baru, Feng-Kun Guo, Christoph Hanhart, Alexey Nefediev

Keyword:

High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), High Energy Physics - Experiment (hep-ex), Nuclear Theory (nucl-th)

journal:

date:

2023-12-08 00:00:00

Abstract

Recently, the Belle Collaboration reported the first observation of a new structure in the $\psi(2S) \gamma$ final state produced in the two-photon fusion process. In the hadronic molecule picture, this new structure can be associated with the shallow isoscalar $D^*\bar{D}^*$ bound state and as such is an excellent candidate for the spin-2 partner of the $X(3872)$ with the quantum numbers $J^{PC}=2^{++}$ conventionally named $X_2$. In this work we evaluate the electronic width of this new state and argue that its nature is sensitive to its total width, the experimental measurement currently available being unable to distinguish between different options. Our estimates demonstrate that the planned Super $\tau$-Charm Facility offers a promising opportunity to search for and study this new state in the invariant mass distributions for the final states $J/\psi\gamma$ and $\psi(2S)\gamma$.

PDF: Production of the spin-2 partner of $X(3872)$ in $e^+e^-$ collisions.pdf