Analysis of A Λ$\frac{0}{b}$ decay mode

This thesis presents a preliminary results for the first observation of the exclusive Λ$\frac{0}{b}$ → Λ${^0}$$\Psi$(2S) decay with a significance of 7.8 σ. The data sample used in this work, corresponding to an integrated luminosity of approximately 5.3 fb${^−1}$, was collected by the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) in proton-proton collisions at √s = 7 TeV. The preliminary relative branching fraction is measured with respect to the normalizing Λ$\frac{0}{b}$ → Λ${^0}$J/ψ decay mode where the ψ(2S) has been reconstructed in the ψ(2S) → µ+µ− decay mode, the Λ${^0}$ → p$\pi$${^-}$ final state and the J/ψ in the µ+µ−. The B“(Λ$\frac{0}{b}$ → Λ${^0}$ ψ(2S“)“)/B$\frac{0}{b}$ (Λ → Λ ${^0}$ J/ψ) has been measured to be 0.66 ±0.11(stat) ±0.07(syst)±0.07(PDG), where the second and third terms are the statistical and systematic uncertainties and the PDG uncertainty term is due to the J/ψ/ψ(2S) relative branching fraction in the dimuon channel. This result is still under review by the CMS collaboration and it is not an official result yet.