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-π0 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 xp = Pmeson/Pbeam > 0.10 is found to be 0.355 ± 0-011stat ± 0.024sys per event, and the ω production rate for xp > 0.05 is measured as 0.585 ± 0.019stat ± 0.033sys 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 ± 2.9stat ± 1.1sys) × 10-5. © 2002 Elsevier Science B.V. All rights reserved.