Protonium annihilation into two mesons in the quark annihilation model

The annihilation of atomic S- and P-states of the proton-antiproton system into two nonstrange mesons is investigated. The annihilation mechanism is d escribed by the non-relativistic A2 quark annihilation model including the P-3(o) quark-antiquark dynamics. Initial stale interaction. containing isos pin and tensor force mixing as based on different potential models for the N (N) over bar system, is included. Branching ratios for the two-mason anni hilation channels display a strong sensitivity on the initial state interac tion. The dependence of branching ratios on the size parameters of the hadr ons, as reflected in the effective hadronic form factors arising in the qua rk model, is explored. Special focus is given to annihilation channels invo lving dynamical selection rules: that is. suppression of transitions which are allowed by the conservation of the J(PC)(I-G) quantum numbers. Results are compared with a previous, simplified approach for two-meson annihilatio n.