The New Physics Effects On The Weak Decays Of B-flavor Hardons

The Standard Model(SM)of elementary particle is the most successful theoretical model in describing the strong and electroweak interactions between the fundamental particles,and it has survived experimental tests.However,it is not perfect,there exist some problems that have not yet been solved reasonably.And there are still some discrepancies by and large between the experimental and theoretical results.All these inconsistency may indicate the SM is not an ultimate theory.It should be an effective theory at low scale.At the higher scale,there should exist some new and more basic theory.Heavy flavor physics offers not only the potential insight into the hadronic dynamics of strong interactions at very short distances,but also a good place to test the SM and study the original of CP violation,rare decays,flavor-changing-neutral-currents(FCNCs).Moreover,it will also provide the proof of the existing new physics(NP)signals.Therefore,the heavy flavor physics is one of the most active frontier areas in particle physics.In this thesis,we study the semilepton decays of b-flavor hardons(such as ∧b baryonic and Bs meson)in some NP models.Firstly,we introduce some basic concepts and theoretical tools,such as the SM,CKM matrix,unitarity triangle,renormalization group,renormalization group equation,operator product expansion,low-energy effective Hamiltonian and Wilson coefficients calculation.Nextly,some schemes employed to calculate the hadronic matrix elements are re-viewed,such as QCD sum-rules and lattice QCD,Finally,we present the main body of our thesis,which is composed of the following two parts:In the vector leptoquark model,scalar leptoquark model,G(221)model and two Higgs dou-blet model(2HDM),we study their effects on some observables of ∧b→∧l+l-decay,such as the differential branching ratios dq2/dBR,the longitudinal polarizations of the dilepton system FL,the lepton-side forward-backward asymmetries AFBμ,the baryon-side forward-backward asym-metries AFB∧ and double lepton polarization asymmetries.In the process of our calculation,for the form factors of ∧b→∧ transition,we use the results of QCD sum rules in low q2 re-gion and lattice QCD in high q2 region,respectively.We find,for the differential branching ratio dq2/dBR,the current experiment data are difficult to be explained in the SM in the ranges of 2<q2<4GeV2/c4,4<Q2<6GeV2/c4,6<q2<8GeV2/c4,16<q2<18GeV2/c4 and 18<q2<20GeV2/c4.When we consider the contributions of these NP models,the experi-mental data in the ranges of 2<q2<4GeV2/c4 and 6<q2<8GeV2/c4 can be explained both in the vector leptoquark model and in the G(221)model,and the experimental data in the ranges of 16<q2<18GeV2/c4 and 18<q2<20GeV2/c4 can be explained in the 2HDM.For the the lepton-side forxward-backward asyrrmmetries AFBμ,the current experiment data are diff1cult to be explained in the SM in the ranges of 15<q2<16GeV2/c4、16<q2<18GeV2/c4 and 18<q2<20GeV2/c4.When we consider the contributions of these NP models,the experi-mental data in the range of 15<q2<16GeV2/c4 can be explained both in the scalar leptoquark X(3,2,7/6)model and 2HDM.For the baryon-side forward-backward asymmetries AFB∧,it is only sensitive to the contributions of scalar leptoquark X(3,2,1/6)models.For the double lep-ton polarization asymmetries PLN,PNL,PNT and PTN,their values of the SM prediction are very small,and they are also not sensitive to the contributions of these NP models.Only PLT、PNN and PTT are sensitive to the contributions of these NP models.In these NP models,we also study their effects on some observables of Bs→Φμ+μ-decay,such as the differential branching ratio dq2/dBR,the longituthe longitudinal polarizations of the dilepton system FL,CP averaged angular coefficients S3、S4 and the double lepton polarization asymmetries.In the process of our calculation,we focus on the low q2 region.For the the form factors of Bs→Φ transition,we use the results of QCD sum rules.We find,for the differential branching ratio dq2/dBR,the current experiment data are difficult to be explained in the SM in the ranges of 2<q2<5GeV2/c4 and 5<q2<8GeV2/c4.When we consider the contributions of these NP models,these data can be explained both in the vector leptoquark model and in the G(221)model.For the the longituthe longitudinal polarizations of the dilepton system FL and CP averaged angular coefficients S3、S4,their experiment data are basically consistent with the prediction values of the SM,For the double lepton polarization asymmetries,only PNN and PTT are sensitive to the contributions of these NP models.With the LHC running further and Super-b in the further,more decay modes will be opened,it will provide us more opportunities to understand and study the heavy flavor hardonic physics.Although this faces some difficulties,its research wiil be valuable and meaningful.