Sharma, Rajeev KumarTavneet Kaur2018-02-072018-02-072017http://krishikosh.egranth.ac.in/handle/1/5810040498The rare decays of B mesons are sensitive to physics processes outside the Standard Model and are an important probe in exploring quantum chromodynamics (QCD). The branching fraction of rare decay mode is an interesting quantity to measure because the contribution from physics beyond Standard Model may be sizable in rare decay mode. Possible new physics enhancements of B0→J/ψγ decay rate include a right handed charged current or non– spectator intrinsic charm in B0 meson. In radiative annihilation decay of B0→J/ψγ, the dominant mechanism is the exchange of W bosons and the radiation of a photon from the light quark of B mesons. The decay of B0→J/ψγ→e+e-/µ+µ- and the reconstruction of B0 mesons is the valid test for the measurement of time–dependent CP violating asymmetries. The data used in this analysis has been collected from Belle Detector at asymmetrical e+e- collider working at ϒ(4S) resonance with a Lorentz Boost (βγ) of 0.425. A signal Monte Carlo 100,000 events are generated by EvtGen to calculate reconstruction efficiency and for background estimation. The reconstruction efficiency of B0→J/ψγ calculated from ∆E is 27.58 ± 0.2% and 27.96 ± 0.2% from Mbc. In this decay mode, the obtained background estimates of 3.7 events for B0→J/ψπº mode and 0.8 for B0→J/ψKL, resulting in total background of 4.5 ± 1.1 events. On comparing Monte Carlo continuum on-resonance and experimental off-resonance data, no significant contribution from continuum background was found.ennullThesis