Production of the P-Wave Excited Bc-States through the Z⁰ Boson Decays

Original · EN

In Ref.[7],we have dealt with the production of the two color-singlet S-wave (cb)-quarkonium states Bc(|(cb) 1[¹S₀]>) and B*c(|(cb) 1[³S₁]>) through the Z⁰ boson decays. As an important sequential work, we make a further discussion on the production of the more complicated P-wave excited (cb)-quarkonium states, i.e. |(cb) 1[¹P₁]> and |(cb) 1[³Pⱼ]> (with J=(1,2,3)). More over, we also calculate the channel with the two color-octet quarkonium states |(cb) 8[¹S₀]g> and |(cb) 8[³S₁]g>, whose contributions to the decay width maybe at the same order of magnitude as that of the color-singlet P-wave states according to the naive nonrelativistic quantum chromodynamics scaling rules. The P-wave states shall provide sizable contributions to the Bc production, whose decay width is about 20% of the total decay width ΓZ₀→ Bc. After summing up all the mentioned (cb)-quarkonium states' contributions, we obtain ΓZ₀→ Bc =235.9⁺³⁵².⁸₋₁₂₂.₀ KeV, where the errors are caused by the main uncertainty sources.