The four-pion final state in p.bar.p annihilations at 5.7 GeV/c

A study is presented of the 4 pi final state in the reaction pp to 2 pi /sup +/2 pi /sup -/ at 5.7 GeV/c. (3 refs)

Analysis of the pp to pp pi /sup +/ pi /sup -/ reaction at 57 GeV/c

In 10960 events of the pp pi /sup +/ pi /sup -/ final state the baryon resonances production and the associated production of Delta (1236) Delta (1236) isobars are studied (48.5+or-2.6)% of Delta /sup ++/ anti Delta /sup ++/ and (4.5+or-0.5)% of Delta /sup 0/ Delta /sup 0/ are found. Study of the various mass spectra shows that they are essentially described by the introduction of Delta /sup ++/ anti Delta /sup ++/ production. Introduction of the strong t dependence of the Delta /sup ++/ anti Delta /sup ++/ changes this description only slightly. A study of the interaction radius of the p pi system reveals a best value of r=1.6+or-0.4 fm. Bumps observed in the p pi /sup +/ pi /sup -/+c.c. system at 1450 and 1690 MeV when treated as resonances give rates of (4.0+or-0.4)% and (4.5+or-0.4)% respectively. It is concluded that the reaction pp to pp pi /sup +/ pi /sup -/ at 5.7 GeV /c proceeds almost entirely via the production of baryon resonances. (8 refs)

The four-pion final state in pp annihilations at 57 GeV/c

577 events from pp to 2 pi /sup +/2 pi /sup -/ annihilations at 5.7 Ge V/c are analysed. Single particle spectra are studied and effective matrix element is determined. The rates for production of rho degrees and f/sup 0/ mesons are estimated and the influence of resonances on the angular distributions of pions and dipions is investigated. Transverse momenta correlations can be explained using peripheral phase space. (17 refs)

The reaction pp to pp pi /sup +/ pi /sup -/ pi /sup 0/ at 57 GeV/c and a p omega /sup 0/ (p omega /sup 0/) enhancement at 1.81 GeV

The final states pp omega and Delta /sup ++/ Delta /sup --/ pi /sup 0 /, produced in the reaction pp to pp pi /sup +/ pi /sup -/ pi /sup 0/ (6435 events) at 5.7 GeV/c, are studied. Cross-sections are presented, and general features of the resonances produced are investigated. Spin alignment of the omega 's, reported earlier, is studied. An enhancement is observed in the omega p( omega p) mass plot of mass (1810+or-15) MeV and width (87+or-20) MeV. (14 refs)