Search for the B(c) meson in hadronic Z(0) decays using the opal detector at LEP.

摘要

A search for decays of the Bc meson was performed using data collected from 1990--1995 with the OPAL detector on or near the Z0 peak at LEP. The decay channels B+c→J/yp +,B+ c→J/ya+ 1 and B+c→J/yℓ +n were investigated, where ℓ denotes an electron or a muon. Two candidates are observed in the mode B+c→J/yp +, with an estimated background of (0.63 +/- 0.20) events. The weighted mean of the masses of the two candidates is (6.32 +/- 0.06) GeV/ c2 , which is consistent with the predicted mass of the Bc meson. One candidate event is observed in the mode B+c→J/yℓ +n, with an estimated background of (0.82 +/- 0.19) events. No candidate events are observed in the B+c →J/ya+1 decay mode, with an estimated background of (1.10 +/- 0.22) events. Upper bounds at the 90% confidence level are set on the production rates for these processes.