Approach to calculation of mass spectra and two-photon decays of ccˉ mesons in the framework of Bethe-Salpeter equation

摘要

In this work we calculate the mass spectra of charmonium for 1 P , … , 4 P states of 0 + + and 1 + + , for 1 S , … , 5 S states of 0 ? + , and for 1 S , … , 4 D states of 1 ? ? along with the two-photon decay widths of the ground and first excited states of 0 + + quarkonia for the process O + + → γ γ in the framework of a QCD-motivated Bethe-Salpeter equation (BSE). In this 4 × 4 BSE framework, the coupled Salpeter equations are first shown to decouple for the confining part of the interaction (under the heavy-quark approximation) and are analytically solved, and later the one-gluon-exchange interaction is perturbatively incorporated, leading to mass spectral equations for various quarkonia. The analytic forms of wave functions obtained are used for the calculation of the two-photon decay widths of χ c 0 . Our results are in reasonable agreement with data (where available) and other models.