The next-to-next-to-leading-order QCD corrections to $e^{+}{e}^{-}\to {\eta }_c/{\chi }_{cJ}+\gamma$ at B factories

Cong Li, Wen-Long Sang, Hong-Fei Zhang

We investigate the processes $e^{+}{e}^{-}\to {\eta }_c+\gamma$ and $e^{+}{e}^{-}\to {\chi }_{cJ}+\gamma$ at B factories within the NRQCD factorization framework, computing the corresponding helicity amplitudes thr…