Proton-antiproton annihilation into three mesons in flight in the 3P 0 model with a planar quark diagram topology

Abstract

pp̄ annihilation into three mesons in flight and partially at rest is analysed in the planar diagram or annihilation model. Three mesons are produced by annihilation of two qq̄ pairs from the initial pp̄ state and by subsequent creation of two qq̄ pairs (A3). In the framework of the constituent quark model it is assumed that the annihilated/created quark pair possesses the quantum numbers of the vacuum ( 3P 0). The meson channels under consideration include a combination of s-wave mesons and maximally one p-wave meson. In combining the annihilation model A3 into three mesons with the annihilation model A2 into two mesons, branching ratios of the pp̄ annihilation at rest and in flight are calculated. By adjusting the relative strength of A3 and A2, the experimental annihilation data are roughly explained. In particular, intermediate two- and three-meson channels leading to the final states π + π − π 0, 2 π +2 π −, 2 π +2 π − π 0, two-prong and four-prong, which make up the dominant contribution in the annihilation process, are reproduced well in the planar diagram model.