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).