SEPARATION OF S-WAVE PSEUDOSCALAR AND PSEUDOVECTOR AMPLITUDES IN PI(-)P-UP-ARROW-]PI(-)N REACTION ON POLARIZED TARGET()PI()

A new analysis of S-wave production amplitudes for the reaction pi(-)p (up arrow) --> pi(+)pi(-)n on a transversely polarized target is perfo rmed. It is based on the results obtained by the CERN-Cracow-Munich co llaboration in the pi pi energy range from 600 MeV to 1600 MeV at 17.2 GeV/c pi(-) momentum. Energy-independent separation of the S-wave pse udoscalar amplitude (pi exchange) from the pseudovector amplitude (a(1 ) exchange) is carried out using assumptions much weaker than those in all previous analyses. We show that, especially around 1000 MeV and a round 1500 MeV, the a(1) exchange amplitude cannot be neglected. The s calar-isoscalar pi pi phase shifts are calculated using fairly weak as sumptions. Below the <K(K)over bar> threshold we find two solutions fo r the pi - pi phase shifts, for which the phases increase slower with the effective pi - pi mass than the P-wave phases. Both solutions are consistent with a broad f(0)(500) but only one is similar to the well- known ''down'' solution. We find also the third solution (with a somew hat puzzling behavior of inelasticity) which exhibits a narrow f(0)(75 0) claimed by Svec. All the solutions undergo a rapid change at the <K (K)over bar> threshold. Above 1420 MeV the phase shifts increase with energy faster than those obtained without the polarized-target data. T his phase behavior as well as an increase of the modulus of the a(1)-e xchange amplitude can be due to the presence of the f(0)(1500).