Branching ratios of antiproton-proton annihilation reactions

The annihilation fractions of the p-pbar annihilation at rest into pi-pi, pi-eta, eta-eta, phi-pi0, K-Kbar and eta(1440)-pi-pi
at different target densities are reviewed in order to determine their branching ratios from S and P antiprotonic atom sublevels and the sublevel population fractions. Particular emphasis is given to the incompatibility of some annihilation fraction measurements and to the expected dependence of
the p-pbar atom sublevel population fractions on the target density. The population fraction of the 3P0
sublevel in liquid target turns out to be higher than its statistical weight.