Inclusive production of the η and ω mesons in Z decays, and the muonic branching ratio of the ω

Abstract The inclusive production of the  η and ω (782) mesons is measured in the π + π − π 0 decay mode in hadronic Z decays and compared to model predictions. The analysis is based on 4 million hadronic Z decays recorded by the ALEPH detector between 1991 and 1995. The  η production rate for x p = p meson / p beam >0.10 is found to be 0.355±0.011 stat ±0.024 sys per event, and the ω production rate for x p >0.05 is measured as 0.585±0.019 stat ±0.033 sys per event. The branching ratio for ω → μ + μ − is investigated. A total of 18.1±5.9 events are observed, from which the muonic branching ratio is measured for the first time to be BR( ω → μ + μ − )=(9.0±2.9 stat ±1.1 sys )×10 −5 .