Testing ${\chi }_c$ properties at BELLE II

Abstract

The model of the ${\chi }_{c_i}-{\gamma }^{\ast }-{\gamma }^{\ast }$ and ${\chi }_{c_i}-J/{\psi }^{\ast }-{\gamma }^{\ast }$ 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 ${\chi }_{c_i}-{\gamma }^{\ast }-\gamma$ 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.