Search For The Rare Decay B~0?J/??

The standard model has achieved great success in physics by now,but it does not explain everything.Dark matter,dark energy in the universe,imbalance between matter and antimatter,and the source of neutrino mass are still unsolved mysteries.Therefore,the search for new physics beyond standard model has become one of the most important tasks in physics,and the study of rare decay can provide great opportunity in search of new physics.LHCb is a specialized physics experiment,designed primarily for the study of bottom and charm quark physics.In this paper,we search for the decay of B0?J/??(J/???+?-),??K+K-).The datasets used correspond to integrated luminosities of approximately 1.0 fb-1 collected at(?)= 7 TeV in 2011 and 2.0 fb-1 at(?)= 8 TeV in 2012.We select Bs/d0?J/?K+K-with K+K-mass less than 1050 MeV using multivariate analysis techniques.The shape parameters of 0(1020)and non-resonant contributions are determined by fitting to the K+K-invariant mass spectrum of Bs0?J/?K+K-candidates,and applied to the fit of the K+K-mass spectrum of Bo B0?J/?K+K-,No evidence of the resonant ?(1020)is observed.By using Bs0?J/?? as the normalization channel,an upper limit on B0 ?J/??branching fraction is set to be 5.51 x 10-7 for 2011 and 1.26 × 10-7 for 2012 at 90%CL,based on the profile likelihood scan.Combining the 2011 and 2012 data samples,we obtain an upper limit of 1.64 × 10-7.Thesis analysis uses only the 2011?2012 data sample corresponding to an integrated luminosity of 3.0 fb-1.Anthor 6.0 fb-1 data is collected at 13 TeV in Run2(2015?2018)by LHCb experiment with the double of the production cross-sections of B mesons.The search sensitivity for B0?J/?? is expected to be greatly improved with Run2 data.