Testing $\chi_c$ properties at BELLE II

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.