Observation Of A New J(Pc)=1(-+) Exotic State In The Reaction Pi(-)P ->Pi(+)Pi(-)Pi(-)P At 18 Gev/C

A partial-wave analysis of the reaction pi(-)p --> pi(+)pi(-)pi(-)p at 18 GeV/c has been performed on a data sample of 250 000 events obtained by Brookhaven experiment E852. The expected J(PC) = l(++)a(1)(1260), 2(++)a(2)(1320), and 2(-+)pi(2)(1670) resonant states are clearly observed. The exotic J(PC) = 1(-+) wave produced in the natural parity exchange processes shows distinct resonancelike phase motion at about 1.6 GeV/c(2) in the rho pi channel. A mass-dependent fit results in a resonance mass of 1593 +/- 8(-47)(+29) MeV/c(2) and a width of 168 +/- 20(-12)(+150) MeV/c(2).