Observation and branching fraction measurement of B+ → ψ(2S) φ K+ at √s = 8 TeV in CMS & Hadron Shower development studies using Geant4 simulations

Heavy quark decays provide an opportunity to test the Standard Model (SM). Recently, promising experiments with b quark, as well as the analysis of the huge data sets produced at the Large Hadron Collider (LHC) accelerator, have led to an increased study and more sensitive measurements of relative b quark decays. In this thesis, a preliminary study is presented of the first time observation of the B+ → ψ(2S)φK+ with a statistical significance above 5 standard deviations using proton- proton collisions at √s = 8 TeV collected with CMS detector at LHC. The branching fraction of B+ → ψ(2S)φK+ is measured relative to B+ → ψ(2S)K+, whose absolute branching fraction (BF) is known. The B(B+ → ψ(2S)φK+) is determined to be (4.0 ± 0.4(stat) ± 0.6(syst) ± 0.1(BR)) × 10−6, where the third uncertainty is from the imprecision in the normalization channel.