anti pp annihilations into four charged mesons from 1.6 to 2.2 GeV/c

The following reactions have been analyzed: (1) p̄p→π⁻π⁻π⁺π⁺; (2) p̄p→π⁻π⁺K⁻K⁺; (3) p̄p→K⁻K⁻K⁺K⁺. Cross sections as a function of beam momentum ranging from 1.6 to 2.2 GeV/c are presented. The percentage of resonance production in reaction (1) is examined using the maximum-likelihood (ML) method. The channel is dominated by ρππ and ρ f production. The percentage of ρ f decreases with p̄ momentum, while ρππ appears to increase. ML fits are also made to reaction (2); the reaction is dominated by K*Kπ, φππ, and ρKK production. An enhancement is seen in the Q region of the ππ K mass spectrum at 1278 MeV, with FWHM (full width at half maximum) of 25 MeV. Six events are consistent with reaction (3). Mass spectra indicate that five events have at least one φ meson produced; one of these is a φφ event.