PWA of 3π Final States and a Search for the π1(1600)

Abstract

Partial wave analyses (PWA) of the 3pi systems in the reactions pi- p --> pi+ pi- pi- p (the ``charged'' mode) and pi- p --> pi- pi0 pi0 p (the ``neutral'' mode) with an 18.3 GeV/c pion beam were performed using high statistics data from the E852 experiment. Conventional signals, such as the a1(1260), the a2(1320), and the pi2(1670), were found to be remarkably stable to the choice of waves included in the fit. In contrast, possible evidence for the pi1(1600) in the JPC = 1-+ exotic wave amplitude disappears when additional decay modes of conventional mesons (especially those of the pi2(1670)) are included in the PWA fit.