Thesis defense of Patrick Mackowiak

This thesis presents two measurements involving a beauty hadron decaying to a charmonium meson and a strange hadron. First, a measurement of the ratio of branching fractions for Λb→ψ(2S)Λ and Λb→J/ψΛ decays is presented. This analysis uses a data set corresponding to 3 fb-1, collected by the LHCb experiment at a centre-of-mass energy of 7 and 8 TeV. The ratio of branching fractions is determined to be BR(Λb→ψ(2S)Λ)/BR(Λb→J/ψΛ)= 0.513 ± 0.023 (stat) ± 0.016 (syst) ± 0.011 (BR).

The second analysis is a on-going measurement of CP violation in g in B0→J/ψKS, B0→ψ(2S)KS and Bs0→J/ψKS decays. The analysed LHCb data sets correspond to 6 fb-1, at a centre-of-mass energy of 13 TeV. The measured sensitivities of the CP parameters S and C in the analysed Bd0 decays are σ(S) = 0.0133 (stat) ± 0.0063 (\syst), σ(C) = 0.0125 (stat) ± 0.0042 (syst). This single measurement will have a better sensitivity than the current world average.