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semileptonic decays B_c →(η_c , J/Ψ)lν in the perturbative QCD approach

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Chinese Physics C 2013年第9期37卷 6-12页

作者：王文飞樊莹莹肖振军 Department of Physics and Institute of Theoretical Physics Nanjing Normal University

In this paper we study the semileptonic decays of Bc→（ηc, J/ψ）1-v1. We first evaluate the Bc→（ηc, J/ψ） transition form factors Fo（q2）, F＋（q2）, V（q2） and Ao,l,2（q2） by employing the pQCD factorization approach, and then we calculate the branching ratios for all considered semileptonic decays. Based on the numerical results and the phenomenological analysis, we find that：（a） the pQCD predictions for the values of the Bc→ηc, and Bc→J/ψ transition form factors agree well with those obtained by using other methods; （b） the pQCD predictions for the branching ratios of the considered decays are Br（B---qe-e（-））= （4.41_1.09）＋1＂22 10-3 Br（B----rl-） ---- （1.37_＋：337） x 10-3, Br（B：--J/kOe-e（li-,））=（iO.03＋：3）〉lO-3, and Br（B：--＊J/＇r-]T）----（2.92_0.34）10＋40 -3., and （c） we also define and calculate two ratios of the branching ratios Rn and Rj/v, which will be tested by LHCb and the forthcoming Super-B experiments.

关键词： pQCD B meson semileptonic decay

Study of semileptonic decays B_s →D_(s1)(2536)l and B_s →D_(s2)(2573)l in the CQM model

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Chinese Physics C 2008年第8期32卷 603-607页

作者：赵树民张印杰阎玉立刘立全武利平 College of Physics Science and Technology Hebei University

Based on the assumption that Ds1（2536） and Ds2（2573） belong to T doublet （1^＋,2^＋）, we calculate the semileptonic decays of Bs to Ds1（2536） and Ds2（2573） in terms of the Constituent Quark Meson （CQM） model. For Bs → Ds1 （2536）＋ lv^- and B→ → Ds2 （2573）＋lv^-, the order of magnitude of the obtained branching ratios is 10^-3. Our numerical results of the semileptonic decays of Bs to Ds1（2536） and Ds2（2573） are large, which implies that two semileptonic decays should be seen in future experiments.

关键词： semileptonic decay CQM model branching ratios

Study of singlet-triplet mixing via semileptonic decays

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Chinese Physics C 2013年第1期37卷 21-26页

作者：姜越王国利王天鸿鞠万里 Department of Physics Harbin Institute of Technology PITT PACC Department of Physics & AstronomyUniversity of Pittsburgh

The singlet-triplet mixing of;P;-3P1 is studied via calculating the branching ratios of semileptonic decay Bs→D;lν and B→D;lν by means of the instantaneous Bethe-Salpeter method. Special attention is paid to the relativistic corrections, since they are large for the P -wave states. Using the Mandelstam Formalism, we compute the transition form factors not only in the high-energy lepton end-point region but also in the full Q2 region. In addition, the non-perturbative QCD effects are taken care of in the overlapping integral over the relativistic wave functions of the initial and final states.

关键词： singlet-triplet mixing semileptonic decay instantaneous Bethe-Salpeter method

Role of hyperfine mixing in b→c semileptonic decays of doubly-heavy baryons

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Chinese Physics C 2010年第9期34卷 1488-1490页

作者： C.Albertus E.Hernández J.Nieves Departamento de Física Fundamental e IUFFyM Universidad de Salamanca Instituto de Física Corpuscular (IFIC) Centro Mixto CSIC-Universidad de ValenciaInstitutos de Investigación de Paterna

We analyze the effects of hyperfine mixing in b → c semileptonic decays of doubly heavy *** qualitatively confirm the results by *** and *** in ***.A,2009,24： 2401– 2413,finding that mixing has a great impact on those ***,predictions without mixing differ by a factor of 2 and this discrepancy translates to the mixed case where large differences in decay widths are observed between the two calculations.

关键词： doubly-heavy baryons semileptonic decay hyperfine mixing

B_((s))→D^(∗∗)_((s))form factors in HQEFT and model independent analysis of relevant semileptonic decays with NP effects

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Chinese Physics C 2023年第10期47卷 55-76页

作者：左亚兵金洪瑶田婧赢伊佳宫涵宇潘婷婷 Department of physics Liaoning Normal UniversityDalian 116029China Center for Theoretical and Experimental High Energy Physics Liaoning Normal UniversityDalian 116029China

The form factors of B(s)decays into P-wave excited charmed mesons(including D∗0(2300),D1(2430),D1(2420),D∗2(2460)and their strange counterparts,denoted generically as D∗∗(s))are systematically calculated via QCD sum rules in the framework of heavy quark effective field theory(HQEFT).We consider contributions up to the next leading order of heavy quark expansion and give all the relevant form factors,including the scalar and tensor ones only relevant for possible new physics *** expressions for the form factors in terms of several universal wave functions are derived via heavy quark *** universal functions can be evaluated through QCD sum ***,the numerical results of the form factors are *** the form factors given here,a model independent analysis of relevant semileptonic decays B(s)→D∗∗(s)lν¯l is performed,including the contributions from possible new physics *** predictions for the differential decay widths,branching fractions,and ratios of branching fractions R(D∗∗(s))may be tested in more precise experiments in the future.

关键词： excited charmed meson form factor HQEFT semileptonic decay NP effects

Isgur-Wise function in Bc decays to charmonium with the Bethe-Salpeter method

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Chinese Physics C 2021年第1期45卷 47-66页

作者： Zi-Kan Geng Yue Jiang Tianhong Wang Hui-Wen Zheng Guo-Li Wang Department of Physics Harbin Institute of TechnologyHarbin 150001China

The heavy quark effective theory vastly reduces the weak-decay form factors of hadrons containing one heavy quark. Many works attempt to directly apply this theory to hadrons with multiple heavy quarks. In this paper,we examine this confusing application by the instantaneous Bethe-Salpeter method from a phenomenological perspective, and give the numerical results for Bc decays to charmonium where the final states include 1S, 1P, 2S, and 2P. Our results indicate that the form factors parameterized by a single Isgur-Wise function deviate substantially from the full ones, especially when excited states are involved. The relativistic corrections(1/mQcorrections) require the introduction of more non-perturbative universal functions, similar to the Isgur-Wise function, which are the overlapping integrals of the wave functions with the relative momentum between the quark and antiquark.

关键词： Isgur-Wise function relativistic correction Bethe-Salpeter equation semileptonic decay

Exclusive semileptonic Rare decays B→K()(?)+(?)^- in a Top Quark Two-Higgs-Doublet Model

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Communications in Theoretical Physics 2008年第7期50卷 149-160页

作者： LV Lin-Xia XIAO Zhen-Jun Department of Physics Nanyang Teacher＇s College Nanyang 473061 China Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing 210097 China

Employing improved calculations of the decay form factors from light-cone sum rules, we evaluate the invariant mass spectrum, forward-backward asymmetry, and lepton polarizations of the exclusive processes B → K^（＊）e＋e- in the SM and T2HDM. From the recent measurements of their branching ratios, we find that these processes do provide additional bounds on the new parameters in the model considered here. After the inclusion of the new physics contributions, the large enhancement of FBA, which is unobservably small within the SM and of the lepton polarization at large tan β, may precisely test the SM or reveal new physics in forthcoming accurate experiments.

关键词： semileptonic decay two-Higgs-doublet model polarization forward-backward asymmetry

Corrections to R_D and R_(D~*) in the BLMSSM

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Chinese Physics C 2018年第11期42卷 33-44页

作者： Zhong-Jun Yang Shu-Min Zhao Xing-Xing Dong Xi-Jie Zhan Hai-Bin Zhang Tai-Fu Feng National-Local Joint Engineering Laboratory of New Energy Photoelectric Devices Department of PhysicsHebei UniversityBaoding 071002China

The deviation of the measurement of RD （RD＊） from the Standard Model （SM） expectation is 2.3σ （3.1σ）. RD （RD＊） is the ratio of the branching fraction of ^-B→Dτ^-υτ （^-B→D^＊τ^-υτ ） to that of ^-B→Dl^-υι （^-B→Dl^-υι）, where l=e or μ. This anomaly may imply the existence of new physics （NP）. In this paper, we restudy this problem in the supersymmetric extension of the Standard Model with local gauged baryon and lepton numbers （BLMSSM）, and give one-loop corrections to RD （RD^＊）.

关键词： supersymmetry BLMSSM semileptonic decay

Revisiting D-mesontwist-2,3 distribution amplitudes

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Chinese Physics C 2023年第5期47卷 73-81页

作者：钟涛黄冬付海冰 Department of Physics Guizhou Minzu UniversityGuiyang 550025China Department of Physics Chongqing UniversityChongqing 401331China

Owing to the significant difference between the experimental measurements and the theoretical predictions of the standard model(SM)for the value of R(D)of the semileptonic decay B→Dtve,researchers speculate that this decay may be evidence of new physics beyond the ***,the D-meson twist-2,3 distribution amplitudes(DAs)Φ2;D(x,μ),d3:D(x,μ),and$g:D(x,μ)are the main error sources when perturbative QCD factorization and light-cone QCD sum rules are used to study B→***,it is important to obtain more reasonable and accurate behaviors for these *** by our previous work[***.D 104,no.1,016021(2021)]on pionic leading-twist DA,we revisit D-meson twist-2,3 DAsΦ2:D(x,μ),Φp3:D(x,μ),andΦσ3:D(x,μ).New sum rule formulae for the-moments of these three DAs are suggested for obtaining more accurate *** light-cone harmonic oscillator models for the DAs are improved,and their parameters are determined by fitting the values of-moments via the least squares method.

关键词： meson distribution amplitude QCD sum rules semileptonic decay