Observation prospects of leptonic and Dalitz decays of pseudoscalar quarkonia

Understand

Two types of pseudoscalar quarkonium electromagnetic decay processes, i.e.

• decay to a lepton pair, and to a lepton pair plus a photon (Dalitz decay), are analyzed at the leading order in NRQCD expansion.
• The former type of processes, highly suppressed in the Standard Model, have been hoped to act as the sensitive probes of the possible new physics.
• The latter type of processes generally possess much greater decay rates than the former, owing to several conspiring factors.