Testing $\chi_c$ properties at BELLE II

TL;DR

This paper extends a form factor model for $ ext{chi}_c$ states to include $ ext{chi}_c_0$ and demonstrates that BELLE II can measure these form factors through specific reactions, using an updated Monte Carlo generator.

Contribution

The study develops an extended model for $ ext{chi}_c$ form factors and shows feasibility of their measurement at BELLE II with a new Monte Carlo tool.

Findings

Feasibility of studying $ ext{chi}_c$ form factors at BELLE II.

Extension of the form factor model to $ ext{chi}_c_0$.

Use of the updated EKHARA Monte Carlo generator.

Abstract

The model of the $\chi_{c_i}-\gamma^*-\gamma^*$ and $\chi_{c_i}-J/\psi^*-\gamma^*$ form factors developed in [1] for $\chi_{c_1}$ and $\chi_{c_2}$ is extended to $\chi_{c_0}$ case. The studies performed within this model have shown that at BELLE II it will be possible to study in detail $\chi_{c_i}-\gamma^*-\gamma$ form factors through measurements of the reaction $e^+e^-\to e^+e^- \chi_{c_i} (\to J/\psi (\to \mu^+\mu^-)\gamma)$.The results were obtained using the newly updated Monte Carlo generator EKHARA.