Research On The Weak Decays Of B_q~* Mesons To The P Wave Heavy Meson

At present,b flavor pseudoscalar mesons(such as B,BS,Bc mesons)have been extensively studied in theory and experiment,but the 1-state vector mesons(such as B*,Bs*,Bc*mesons still lack sufficient experimental results.because the generation rate and the detection efficiency of vector mesons are much lower than the pseudoscalar mesons.For example,there are about 107 Bc*mesons generated in LHC with running in 14 TeV.With the further improvement of the LHC brightness in the future,it is expected that the LHCb detector will collect more vector meson data,making it possible to detect vector mesons.In addition,the Belle Ⅱ and SuperKEKB collaboration as "B-Factory" will also provide more information about vector particles.Due to the limitation of mass threshold,Bq*mesons(q=u,c,d,s)cannot undergo strong decay.This article mainly studies their weak decay processes,including semileptonic decay and nonleptonic decay processes.In this paper,the instantaneous approximation Bethe-Salpeter method is used to study the matrix elements of the hadron transition.By solving the instantaneous BS equation,the positive energy wave function of the initial and final state meson is derived,and the hadron transition matrix element is the integral form of the initial and final BS positive energy wave function.This method takes into account the influence of relativitic correction.Then through the phase space integration of the Feynman amplitude square,the width and branch ratio of the semileptonic decay and nonleptonic decay process are obtained,and the distribution spectrum of the differential branch ratio in the semiletonic decay with respect to the final state lepton energy is given,in order to better compare and verify with experimental data.This article considers the cases where the final meson is 0+state,1+state,1+’ state and 2+ state.Among them,the decay width of the semileptonic decay from 1-state to 0+state is of the order 10-16 GeV,and the decay width of nonleptonic decay is of the order 10-14 GeV.For the mixed state 1+state and 1+’ state,since the final meson is composed of quarks of different flavors,the final meson does’t have a definite C parity.This article adopts the mixing method of the state vector of P wave to constructs the 1+state and the 1+’ state.In the end,the decay width of the semileptonic decay from the 1-state to the 1+state is of the order 10-15 GeV,and the decay width of the nonleptonic decay is of the order 10-12 GeV.The decay width of the semileptonic decay from the 1-state to the 1+’ state is of the order 10-15 GeV,and the decay width of the nonleptonic decay is of the order 10-12 GeV.When we make the 1++state and 1+-state mixing,this paper uses the value of the ideal mixs angle?θ=35.3°,and gives the branch ratio variety of final mesons which is 1+state and 1+’ state when the mixing angle is changed.When the final meson is 2+state,the calculation process will be more cumbersome.It is necessary to introduce the polarization vector and polarization tensor to describe the initial and final state mesons,and calculate their polarization in the Feynman amplitude square.the decay width of the semileptonic decay from the 1-state to the 2+state is of the order 10-14 GeV,and the decay width of the nonleptonic decay is of the order 10-11 GeV.