Study of ηπ- and π+π-π- systems in π-p interactions at 18 GeV/c

The exclusive reactions pi(-)p --> eta pi(-)p and pi(-)p -->, pi(+)pi(-)pi(-)p at 18 GeV/c have been studied at the MultiParticle Spectrometer at Brookhaven National Laboratory. Partial wave analyses have been performed on the 47,200 eta pi(-)p events and 250,000 pi(+)pi(-)pi(-)p events. In eta pi(-) a J(PC) = 1(-+) exotic state of mass (1370 +/- 16(-30)(+50))MeV/c(2) and width (385 +/- 40(-105)(+65) MeV/c(2)) is seen to interfere with the a(2)(1320) with resonance-like phase motion, while in pi(+)pi(-)pi(-) a J(PC) 1(-+) exotic wave is observed with resonance-like behavior at a mass of (1533 +/- 8 MeV/c(2)) and width (158 +/- 20 MeV/c(2)).