Further study of the helicity selection rule evading mechanism in ${\eta }_c$, ${\chi }_{c0}$ and $h_c$ decaying to baryon anti-baryon pairs

We investigate the long distance contribution via charmed hadron loops in the processes ${\eta }_c$, ${\chi }_{c0}$ and $h_c$ decaying to baryon anti-baryon pairs, which are supposed to be highly suppressed by the helicity selection rule as a consequence of the perturbative QCD framework. With an effective Lagrangian method, our estimation result indicates that such hadron loops play an important role in these hadronic decays. It is a further test of the evading mechanism for the helicity selection rule in charmonium baryon-antibaryon decays.