New Physics Effects In Exclusive B?u(c)??_? Processes

During the last decades,the standard model of particle physics,which is designed to de-scribe the interaction and motion laws of the elementary particles,has withstood almost all the tests of high-energy-physics experiments.It is therefore regarded as a very successful theory.Once the nineteen free parameters contained in this theory are determined,the properties and interaction laws of all elementary particles can be predicted theoretically.However,it is not the ultimate theory.Because it does not contain the gravitational interaction which is one of the four basic interactions in the nature.In addition,it can not describe correctly the mass of neutrinos,the dark matter and the dark energy,as well as the baryogenesis and so on.Because of these deficits,people have been searching for new physics beyond the Standard Model for decades.As far as the searches for new physics above the electroweak energy scale ?EW(?)246GeV,besides the direct detection of any new elementary particles,we can also capture indirectly the new physics effects in some low-energy flavor physics processes,which are induced after decou-pling the new particles.In the introduction,we enumerate some possible new physical signals in the semileptonic B-meson decays,which are reflected mainly by the violation of lepton flavor university.This paper mainly explores the possible new physical effects in the flavour changing charged current processes b b ? u(c)???,especially the effects of lepton flavor university vio-lation in these processes.The exclusive processes studied by us consist mainly of B ????,B?????,B ?D???,Bc??c???,B ? ????,B?D*???,and Bc?J/???,Firstly,we have calculated the ratios of branching fractions R(M)?B(B?M???))/B(B?M???),where M represents the final-state meson,within the Standard Model.We assume that the new physics only has a significant impact on the processes with a? lepton in the final state,while its effect in the processes involving ?=e,?is very small and hence negligible.Due to the stringent constraint on the pseudoscalar operator by the Bc B???? decay and the mixing of(pseudo)scalar and tensor operators after the electroweak renormalization group evolution,we discuss mainly the new physics contributions to the vector and axial-vector operators,with the corresponding Wilson coefficients given by Cv ?(CV1 + CV2)/2 and CA=(CV2-CV1)/2,respectively.We use firstly the experimental values of R(D),R(D*),R(J/?)and R(?)to limit the parameter space of(CV1,CV2).And then we use the obtained parameter space to predict the differential branching fractions of B?????,Bc??c???,and B ? ????,as well as the corresponding ratios R(?),R(?c)and R(?).We find that the new physics has significant impacts on these phys-ical observables.More accurate experimental measurements in the future can help us to better understand the possible new physics effects in these b ?u(c)??? processes.