Studies On Semileptonic Rare Decays Of B,Bs To P-wave Light Tensor Mesons

Heavy meson exclusive decays play an important role in testing the standard model of particle physics(SM),probing new physics beyond the SM,and determining its basic parameters.Among these,the rare decays induced by the flavor changing neutral current(FCNC)are generated by loop effects in the SM and therefore are very sensitive to new physics.B,Bs both contain a b quark and are typical heavy mesons.These decays can be dealt with via the heavy quark expansion.Furthermore,due to rich physical contents,the relevant rare decays are ideal places for testing the SM and looking for new physics.At present,there are many studies on the processes with the final states containing only S-wave mesons(scalar and vector mesons),while there are few studies on the decays involving P-wave mesons.In this thesis,we intend to give a systematic study on the rare semileptonic decays of B,Bs to light P-wave tensor mesons by using the light cone sum rules(LCSR)in the framework of heavy quark effective field theory(HQEFT).First of all,we give a brief review for the relevant research background and theoretical framework,which mainly includes two parts,i.e.the status of experiments on B,Bs rare semileptonic decays and physical properties of P-wave mesons.In the working part,the transition form factors of B,Bs to light P-wave tensor mesons(a,(1320),K2*(1430),f2(1270),f2(1525))are calculated by using the LCSR in the framework of HQEFT.The light cone distribution amplitudes(DAs)of tensor mesons are consider to twist-3 and the series expansion are adopted in the parameterization of form factors.With the form factors given here,we give a systematic study on relevant FCNC induced rare semileptonic decays.The branching ratio BR,longitudinal polarization fraction<FL>,forward-backward asymmetry<AFB>and angular distribution observables<P1>,<P2>,<P'4'>,<P'5'>are measured in bins of dilepton invariant mass square(q2).It is found that the the branching ratios reaches the order of O(10-8)and the uncertainties are about 15%,mainly come from the form factors.In contrast,other observables are defined via the ratios of amplitudes and corresponding uncertainties are much smaller.In addition,we also consider the contributions of new physics to the above obseravables model independently.These effects of new physics are all appear as corrections to the Wilson coefficients C9,10 eff.In total,we consider 4 new physics scenarios.Research shows that the predictions of SM and different new physics scenarios are similar for most observable,while there are also some observables which have quite different results.These results may be tested by more precise experiments in the future and used to distinguish different new physics models.