A study of the ωη system produced in the reaction π-p→ π+π-4γ n at 18 GeV/c

Results are presented on a study of structure in the omega eta final state produced in pi(-)p interactions at 18 GeV/c where omega --> pi(+)pi(-)pi(0), pi(0) --> 2 gamma, and eta --> 2 gamma. In the extended flux tube model, the omega eta decay of an isoscalar J(PC) = 1(--) hybrid meson is expected. The observed omega eta invariant mass distribution rises rapidly from threshold but in general shows no obvious indication of resonant structure. However the result of a partial wave analysis finds both a J(PC) = 1-- signal consistent with the previously observed omega(1600) and a dominant J(PC) = 1(+-) partial wave which exhibits phase motion relative to the omega(1600). The decay omega(1600) --> omega eta has not been previously reported.