Observation of the π(1800) and π2(1880) mesons in ηηπ− decay

A partial-wave analysis of the reaction π − p → η η π − p at 18 GeV/c has been performed on a data sample of approximately 4000 events obtained by Brookhaven experiment E852. The J P C = 0 − + π ( 1800 ) state is observed in the a 0 ( 980 ) η and f 0 ( 1500 ) π decay modes. It has a mass of 1876 ± 18 ± 16 MeV / c 2 and a width of 221 ± 26 ± 38 MeV / c 2 . The J P C = 2 − + π 2 ( 1880 ) meson is observed decaying through a 2 ( 1320 ) η . It has a mass of 1929 ± 24 ± 18 MeV / c 2 and a width of 323 ± 87 ± 43 MeV / c 2 . Both states are potential candidates for non-exotic hybrid mesons.