Bethe-Salpeter dynamics for two-photon processes

Abstract

Recent experimental data on single hadron production by two-photon beams in PETRA and PEP have provided a unique opportunity for testing specific models of confinement through a study of one of their cleanest predictions viz the γγ→H amplitudes. Motivated by this new facility, a QCD-oriented Bethe-Salpeter model of harmonic confinement, which has already been found to describe rather well several classes of hadronic data (from mass spectra to electromagnetic and pionic couplings), is now employed for a detailed comparison of its predictions on P→ γγ and T → γγ couplings with the data. The agreement is quite good for all cases except one (η → γγ).