The following article has been retracted due to the investigation of complaints received against it. Mr. Mohammadali Ghorbani (corresponding author and also the last author) cheated the author’s name: Alireza Heidari...The following article has been retracted due to the investigation of complaints received against it. Mr. Mohammadali Ghorbani (corresponding author and also the last author) cheated the author’s name: Alireza Heidari. The scientific community takes a very strong view on this matter and we treat all unethical behavior such as plagiarism seriously. This paper published in Vol.3 No.2, 208-213, 2012, has been removed from this site.展开更多
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^（＊...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.展开更多
In the framework of the heavy quark effective theory, the leading order Isgur-Wise functions relevant to semileptonie decays of the orbitally P-wave excited Bs meson states Bs＊, including the newly found narrow Bs1 ...In the framework of the heavy quark effective theory, the leading order Isgur-Wise functions relevant to semileptonie decays of the orbitally P-wave excited Bs meson states Bs＊, including the newly found narrow Bs1 （5830） andBs2（5840） states, into the （Ds1（2536）, Ds2（2573）） doublet are calculated from QCD sum rules. With these universal form factors, the decay rates and branching ratios are also estimated.展开更多
Motivated by our previous study[Phys.Rev.D 104(1),016021(2021)]on the pionic leading-twist distribution amplitude(DA),we revisit theρ-me son leading-twist longitudinal DAφ_(2;ρ)^(‖)(x,μ)in this study.A model prop...Motivated by our previous study[Phys.Rev.D 104(1),016021(2021)]on the pionic leading-twist distribution amplitude(DA),we revisit theρ-me son leading-twist longitudinal DAφ_(2;ρ)^(‖)(x,μ)in this study.A model proposed by Chang based on the DYyson-Schwinger equations is adopted to describe the behavior ofφ_(2;ρ)^(‖)(x,μ).However,theξ-moments ofφ_(2;ρ)^(‖)(x,μ)are calculated with the QCD sum rules in the framework of the background field theory.The sum rule formulas for these moments are improved.More accurate values for the first five nonzeroξ-moments at the typical scaleμ=(1.0,1.4,2.0,3.0)GeV are given,e.g.,atμ=1 GeV,(ξ^(2))>_(2;ρ)^(‖)=0.220(6),(ξ^(4))>_(2;ρ)^(‖)=0.103(4),(ξ^(6))>_(2;ρ)^(‖)=0.066(5),(ξ^(8))>_(2;ρ)^(‖)=0.046(4),and(ξ^(10))>_(2;ρ)^(‖)=0.035(3).By fitting these values with the least squares method,the DSE model forφ_(2;ρ)(x,μ)is determined.By taking the left-handed current light-cone sum rule approach,we obtain the transition form factor in the large recoil region,i.e.,A_(1)(0)=0.498_(-0.012)^(+0.014),A_(2)(0)=0.460_(-0.047)^(+0.055),and V(0)=0.800_(-0.014)^(+0.015),and the ratio r_(2)=0.923_(-0.119)^(+0.133),rV=1.607_(-0.071)^(+0.071).After extrapolating with a rapidly converging series based on z(t)-expansion,we present the|V_(cd)|-independent decay width for the semileptonic decays D→ρ^(l+)v_(l).Finally,the branching fractions are B(D^(0)→ρ^(-)e+v_(e))=1.825_(-0.162)^(+0.170)±0.004,B(D^(+)→ρ^(0)e+v_(e))=2.299_(-0.204)^(+0.214)±0.011,B(D^(0)→ρ^(-)μ^(+)v_(μ))=1.816_(-0.160)^(+0.168)±0.004,and B(D^(+)→ρ^(0)μ+v_(μ))=2.288_(-0.201)^(+0.212)±0.011.展开更多
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 r...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 effects.The expressions for the form factors in terms of several universal wave functions are derived via heavy quark expansion.These universal functions can be evaluated through QCD sum rules.Then,the numerical results of the form factors are presented.With 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 effects.Our 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.展开更多
The static properties and semileptonic decays of ground-state doubly heavy baryons are studied in the framework of a non-relativistic quark model.Using a phenomenological potential model,we calculate the ground-state ...The static properties and semileptonic decays of ground-state doubly heavy baryons are studied in the framework of a non-relativistic quark model.Using a phenomenological potential model,we calculate the ground-state masses and magnetic moments of doubly heavy Ω and Ξ baryons.In the heavy quark limit,we introduce a simple form of the universal Isgur-Wise function used as the transition form factor and then investigate the exclusive b→c semileptonic decay widths and branching fractions for 1/2→1/2 baryon transitions.Our obtained results are in agreement with other theoretical predictions.展开更多
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） mod...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.展开更多
Recently,the BESⅢcollaboration has reported numerous measurements of various D(s)meson semileptonic decays with significantly improved precision.Together with similar studies carried out at BABAR,Belle,and CLEO,new w...Recently,the BESⅢcollaboration has reported numerous measurements of various D(s)meson semileptonic decays with significantly improved precision.Together with similar studies carried out at BABAR,Belle,and CLEO,new windows to a better understanding of weak and strong interactions in the charm sector have been opened.In light of new experimental data,we review the theoretical description and predictions for the semileptonic decays of D(s)to a pseudoscalar or a vector meson.This review is essentially an extended discussion of our recently published results obtained in the framework of the covariant confining quark model.展开更多
Using the covariant light-front approach with conventional vertex functions, we estimate the production rates of D-wave charmed/charmed-strange mesons via the B_((s)) semileptonic decays. As the calculated production ...Using the covariant light-front approach with conventional vertex functions, we estimate the production rates of D-wave charmed/charmed-strange mesons via the B_((s)) semileptonic decays. As the calculated production rates are significant, it seems possible to experimentally search for D-wave charmed/charmed-strange mesons via semileptonic decays, which may provide an additional approach for exploring D-wave charmed/charmed-strange mesons.展开更多
We study the semileptonic B/Bs→(D^(?),D^(?)s)lνl decays in the framework of the Standard Model(SM),by employing the perturbative QCD(PQCD)factorization formalism combined with the lattice QCD input for the relevant ...We study the semileptonic B/Bs→(D^(?),D^(?)s)lνl decays in the framework of the Standard Model(SM),by employing the perturbative QCD(PQCD)factorization formalism combined with the lattice QCD input for the relevant transition form factors.We calculate the branching ratios B(B(s)→D^(?)(s)lνl)with l=(e,μ,τ),the ratios of the branching fractions R(D^(?))and R(D^(?)s),and the physical observables Pτ(D^(?)(s)),FL(D?(s))and AFB(τ).The“PQCD+Lattice”predictions for B(B→D^(?)lνl)and R(D^(?))agree with the available experimental measurements within errors.For the ratios R(Ds)and R(D^?s),the"PQCD+Lattice"predictions agree with the other predictions.For Pτ(D^?)and FL(D^?),our theoretical predictions agree with the measured values within errors.Our theoretical predictions of the semileptonic B/Bs decays considered could be tested in the near future by the LHCb and Belle II experiments.展开更多
While the standard model is the most successful theory to describe all the interactions and constituents of elementary particle physics,it has been constantly scrutinized for over four decades.Weak decays of charm qua...While the standard model is the most successful theory to describe all the interactions and constituents of elementary particle physics,it has been constantly scrutinized for over four decades.Weak decays of charm quarks can be used to measure the coupling strength between quarks in different families and serve as an ideal probe for CP violation.As the lowest charm-strange baryons with three different flavors,Ξ;baryons(composed of csu or csd)have been extensively studied in experiments.In this study,we use state-of-the-art lattice QCD techniques to generate 2+1 clover fermion ensembles with two lattice spacings,a=(0.108,0.080 fm).Then,we present the first ab-initio lattice QCD calculation of the Ξ;→Ξ form factors.Our theoretical results for the Ξc→Ξl;v;decay widths are consistent with and approximately two times more precise than the latest measurements by the ALICE and Belle collaborations.Based on the latest experimental measurements,we independently obtain the quark-mixing matrix element |V;|,which is in good agreement with results from other theoretical approaches.展开更多
We study the semileptonic decaysBc-→(ηc,J/ψ)l-■lusing the PQCD factorization approach with the newly defined distribution amplitudes of the B c meson and a new kind of parametrization for extrapolating the form fa...We study the semileptonic decaysBc-→(ηc,J/ψ)l-■lusing the PQCD factorization approach with the newly defined distribution amplitudes of the B c meson and a new kind of parametrization for extrapolating the form factors which takes into account the recent lattice QCD results.We find the following main results:(a)the PQCD predictions of the branching ratios of theBc→(ηc,J/ψ)l■decays are smaller by about 5%-16%when the lattice results are taken into account in the extrapolation of the relevant form factors;(b)the PQCD predictions of the ratio Rηc,RJ/ψand of the longitudinal polarization PτareRηc=0.34±0.01,RJ/ψ=0.28±0.01,Pτ(ηc)=0.37±0.01and Pτ(J/ψ)=-0.55±0.01;and(c)after including the lattice results,the theoretical predictions slightly change:Rηc=0.31±0.01,RJ/ψ=0.27±0.01,Pτ(ηc)=0.36±0.01andPτ(J/ψ)=-0.53±0.01.The theoretical predictions of RJ/ψagree with the measurements within the errors.The other predictions could be tested by the LHCb experiment in the near future.展开更多
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 factorizatio...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.展开更多
We analyze the effects of hyperfine mixing in b → c semileptonic decays of doubly heavy baryons.We qualitatively confirm the results by W.Roberts and M.Pervin in Int.J.Mod.Phys.A,2009,24： 2401– 2413,finding that mi...We analyze the effects of hyperfine mixing in b → c semileptonic decays of doubly heavy baryons.We qualitatively confirm the results by W.Roberts and M.Pervin in Int.J.Mod.Phys.A,2009,24： 2401– 2413,finding that mixing has a great impact on those transitions.However,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.展开更多
In this work we study the semileptonic decay of Bs^-0→φI^+I^-(l=e,μ,τ) with the QCD sum rule method. We calculate the Bs^-0→φ ftranslation form factors relevant to this semileptonic decay, then the branching rat...In this work we study the semileptonic decay of Bs^-0→φI^+I^-(l=e,μ,τ) with the QCD sum rule method. We calculate the Bs^-0→φ ftranslation form factors relevant to this semileptonic decay, then the branching ratios of Bs^-0→φI^+I^-(l=e,μ,τ)decays are calculated with the form factors obtained here. Our result for the branching ratio of Bs^-0→φμ^+μ^- agree very well with the recent experimental data. For the unmeasured decay modes such as Bs^-0→φe^+e^- and Bs^-0→τ^+τ……-, we give theoretical predictions.展开更多
The singlet-triplet mixing of 1P1-3P1 is studied via calculating the branching ratios of semileptonic decay Bs→Ds1lν and B→D1lν by means of the instantaneous Bethe-Salpeter method. Special attention is paid to the...The singlet-triplet mixing of 1P1-3P1 is studied via calculating the branching ratios of semileptonic decay Bs→Ds1lν and B→D1lν 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. And the non-perturbative QCD effects are taken care of in the overlapping integral over the relativistic wave functions of the initial and nial states.展开更多
In this article, we calculate the B＊→ηc form-factors with the three-point QCD sum rules, then study the semileptonic decays B＊→ηclυl. The tiny decay widths may be observed experimentally in the future at the LH...In this article, we calculate the B＊→ηc form-factors with the three-point QCD sum rules, then study the semileptonic decays B＊→ηclυl. The tiny decay widths may be observed experimentally in the future at the LHCb, while the B＊→ηc form-factors can be taken as basic input parameters in other phenomenologieal analysis.展开更多
We study the semileptonic decays of the lowest-lying bc baryons to the lowest-lying cc baryons （Ξ （＊） bc → Ξ （＊） cc and Ω （ ＊） bc → Ω （＊） cc ）,in the limit m b,m c Λ QCD and close to the zero reco...We study the semileptonic decays of the lowest-lying bc baryons to the lowest-lying cc baryons （Ξ （＊） bc → Ξ （＊） cc and Ω （ ＊） bc → Ω （＊） cc ）,in the limit m b,m c Λ QCD and close to the zero recoil point.The separate heavy quark spin symmetries make it possible to describe all these decays using a single form factor.We also show how these constraints can be used to test the validity of different quark model calculations.bb to bc baryon decays are also discussed.展开更多
In this paper,we investigate the charmed meson rare decay process D^(+)→π^(+)v■using an approach based on QCD sum rules.First,the pion twist-2,3 distribution amplitude(DA)moments<ξ_(2)^(n);|μand<ξ3;π(p,σ...In this paper,we investigate the charmed meson rare decay process D^(+)→π^(+)v■using an approach based on QCD sum rules.First,the pion twist-2,3 distribution amplitude(DA)moments<ξ_(2)^(n);|μand<ξ3;π(p,σ),n>|μ,are calculated up to the tenth and fourth orders,respectively,in the QCD sum rules according to the background field theory.After constructing the light-cone harmonic oscillator model for the pion twist-2,3 D As,we obtain their behaviors by matching the calculatedξ-moments.Then,the D→πtransition form factors(TFFs)are calculated using an approach based on QCD light-cone sum rules.The vector form factor at the large recoil region is f_(+)^(D)→^(π)(0)=0.627_(-0.080)^(+0.120).Using the rapidly converging simplified series expansion of z(q^(2),t),we present the TFFs and corresponding angular coefficients in the whole squared momentum transfer physical region.Based on nonstandard neutrino interactions,the■^(0)→π^(+)e■_(e)decay can be related to the■^(0)→π^(+)e■_(e)decay indirectly.Thus,we first describe the semileptonic decay process■^(0)→π^(+)e■_(e),differential decay widths,and branching fraction with B(■^(0)→π^(+)e■_(e))=0.308_(-0.066)^(+0.155)×10^(2).The■^(0)→π^(+)e■_(e)differential/total predictions for forward-backward asymmetry,q^(2)-differential flat terms,and lepton polarization asymmetry are also reported.The prediction for the D^(+)→π^(+)v■branching fraction isB(D^(+)→π^(+)v■)=1.85_(-0.46)+^(0.93)×10^(-8).展开更多
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...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 SM.Usually,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→Dtve.Therefore,it is important to obtain more reasonable and accurate behaviors for these DAs.Motivated by our previous work[Phys.Rev.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 values.The 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.展开更多
文摘The following article has been retracted due to the investigation of complaints received against it. Mr. Mohammadali Ghorbani (corresponding author and also the last author) cheated the author’s name: Alireza Heidari. The scientific community takes a very strong view on this matter and we treat all unethical behavior such as plagiarism seriously. This paper published in Vol.3 No.2, 208-213, 2012, has been removed from this site.
基金National Natural Science Foundation of China under Grant No.10575052the Specialized Research Fund for the Doctoral Program of Higher Education (SRFDP) under Grant No.20050319008
文摘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.
基金Supported by the National Natural Science Foundation of China under Grant No. 10975184
文摘In the framework of the heavy quark effective theory, the leading order Isgur-Wise functions relevant to semileptonie decays of the orbitally P-wave excited Bs meson states Bs＊, including the newly found narrow Bs1 （5830） andBs2（5840） states, into the （Ds1（2536）, Ds2（2573）） doublet are calculated from QCD sum rules. With these universal form factors, the decay rates and branching ratios are also estimated.
基金Supported in part by the National Natural Science Foundation of China(12265009,12265010,12147102)the Project of Guizhou Provincial Department of Science and Technology(ZK[2021]024,ZK[2023]142)+1 种基金the Project of Guizhou Provincial Department of Education(KY[2021]030)the Chongqing Graduate Research and Innovation Foundation(ydstd1912)。
文摘Motivated by our previous study[Phys.Rev.D 104(1),016021(2021)]on the pionic leading-twist distribution amplitude(DA),we revisit theρ-me son leading-twist longitudinal DAφ_(2;ρ)^(‖)(x,μ)in this study.A model proposed by Chang based on the DYyson-Schwinger equations is adopted to describe the behavior ofφ_(2;ρ)^(‖)(x,μ).However,theξ-moments ofφ_(2;ρ)^(‖)(x,μ)are calculated with the QCD sum rules in the framework of the background field theory.The sum rule formulas for these moments are improved.More accurate values for the first five nonzeroξ-moments at the typical scaleμ=(1.0,1.4,2.0,3.0)GeV are given,e.g.,atμ=1 GeV,(ξ^(2))>_(2;ρ)^(‖)=0.220(6),(ξ^(4))>_(2;ρ)^(‖)=0.103(4),(ξ^(6))>_(2;ρ)^(‖)=0.066(5),(ξ^(8))>_(2;ρ)^(‖)=0.046(4),and(ξ^(10))>_(2;ρ)^(‖)=0.035(3).By fitting these values with the least squares method,the DSE model forφ_(2;ρ)(x,μ)is determined.By taking the left-handed current light-cone sum rule approach,we obtain the transition form factor in the large recoil region,i.e.,A_(1)(0)=0.498_(-0.012)^(+0.014),A_(2)(0)=0.460_(-0.047)^(+0.055),and V(0)=0.800_(-0.014)^(+0.015),and the ratio r_(2)=0.923_(-0.119)^(+0.133),rV=1.607_(-0.071)^(+0.071).After extrapolating with a rapidly converging series based on z(t)-expansion,we present the|V_(cd)|-independent decay width for the semileptonic decays D→ρ^(l+)v_(l).Finally,the branching fractions are B(D^(0)→ρ^(-)e+v_(e))=1.825_(-0.162)^(+0.170)±0.004,B(D^(+)→ρ^(0)e+v_(e))=2.299_(-0.204)^(+0.214)±0.011,B(D^(0)→ρ^(-)μ^(+)v_(μ))=1.816_(-0.160)^(+0.168)±0.004,and B(D^(+)→ρ^(0)μ+v_(μ))=2.288_(-0.201)^(+0.212)±0.011.
基金the National Natural Science Foundation of China(12147214)。
文摘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 effects.The expressions for the form factors in terms of several universal wave functions are derived via heavy quark expansion.These universal functions can be evaluated through QCD sum rules.Then,the numerical results of the form factors are presented.With 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 effects.Our 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.
基金Supported by Kosar University of Bojnord(Grant No.0011191444)。
文摘The static properties and semileptonic decays of ground-state doubly heavy baryons are studied in the framework of a non-relativistic quark model.Using a phenomenological potential model,we calculate the ground-state masses and magnetic moments of doubly heavy Ω and Ξ baryons.In the heavy quark limit,we introduce a simple form of the universal Isgur-Wise function used as the transition form factor and then investigate the exclusive b→c semileptonic decay widths and branching fractions for 1/2→1/2 baryon transitions.Our obtained results are in agreement with other theoretical predictions.
基金Natural Science Fund of Hebei Province (A2005000090,E2005000129)Fund of Education Department of HebeiProvince (2007409)Natural Science Fund of Hebei University (2005007)
文摘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.
文摘Recently,the BESⅢcollaboration has reported numerous measurements of various D(s)meson semileptonic decays with significantly improved precision.Together with similar studies carried out at BABAR,Belle,and CLEO,new windows to a better understanding of weak and strong interactions in the charm sector have been opened.In light of new experimental data,we review the theoretical description and predictions for the semileptonic decays of D(s)to a pseudoscalar or a vector meson.This review is essentially an extended discussion of our recently published results obtained in the framework of the covariant confining quark model.
基金Supported by the National Natural Science Foundation of China(11222547,11175073,11647301)the National Program for Support of Top-notch Young Professionalsthe Fundamental Research Funds for the Central Universities
文摘Using the covariant light-front approach with conventional vertex functions, we estimate the production rates of D-wave charmed/charmed-strange mesons via the B_((s)) semileptonic decays. As the calculated production rates are significant, it seems possible to experimentally search for D-wave charmed/charmed-strange mesons via semileptonic decays, which may provide an additional approach for exploring D-wave charmed/charmed-strange mesons.
基金Supported by the National Natural Science Foundation of China (11775117,11235005).
文摘We study the semileptonic B/Bs→(D^(?),D^(?)s)lνl decays in the framework of the Standard Model(SM),by employing the perturbative QCD(PQCD)factorization formalism combined with the lattice QCD input for the relevant transition form factors.We calculate the branching ratios B(B(s)→D^(?)(s)lνl)with l=(e,μ,τ),the ratios of the branching fractions R(D^(?))and R(D^(?)s),and the physical observables Pτ(D^(?)(s)),FL(D?(s))and AFB(τ).The“PQCD+Lattice”predictions for B(B→D^(?)lνl)and R(D^(?))agree with the available experimental measurements within errors.For the ratios R(Ds)and R(D^?s),the"PQCD+Lattice"predictions agree with the other predictions.For Pτ(D^?)and FL(D^?),our theoretical predictions agree with the measured values within errors.Our theoretical predictions of the semileptonic B/Bs decays considered could be tested in the near future by the LHCb and Belle II experiments.
基金Supported in part by Natural Science Foundation of China(11735010,U2032102,11653003,12005130,11521505,12070131001,11975127,11935017,12005130,12125503)Natural Science Foundation of Shanghai(15DZ2272100)+5 种基金the China Postdoctoral Science Foundation and the National Postdoctoral Program for Innovative Talents(BX20190207)National Key Research and Development Program of China(2020YFA0406400)Jiangsu Specially Appointed Professor Programthe Strategic Priority Research Program of Chinese Academy of Sciences(XDB34030300,XDPB15)a NSFC-DFG joint grant(12061131006,SCHA 458/22)Chinese Academy of Science CAS Strategic Priority Research Program of Chinese Academy of Sciences(XDC01040100)。
文摘While the standard model is the most successful theory to describe all the interactions and constituents of elementary particle physics,it has been constantly scrutinized for over four decades.Weak decays of charm quarks can be used to measure the coupling strength between quarks in different families and serve as an ideal probe for CP violation.As the lowest charm-strange baryons with three different flavors,Ξ;baryons(composed of csu or csd)have been extensively studied in experiments.In this study,we use state-of-the-art lattice QCD techniques to generate 2+1 clover fermion ensembles with two lattice spacings,a=(0.108,0.080 fm).Then,we present the first ab-initio lattice QCD calculation of the Ξ;→Ξ form factors.Our theoretical results for the Ξc→Ξl;v;decay widths are consistent with and approximately two times more precise than the latest measurements by the ALICE and Belle collaborations.Based on the latest experimental measurements,we independently obtain the quark-mixing matrix element |V;|,which is in good agreement with results from other theoretical approaches.
基金Supported by the National Natural Science Foundation of China(11775117,11235005)
文摘We study the semileptonic decaysBc-→(ηc,J/ψ)l-■lusing the PQCD factorization approach with the newly defined distribution amplitudes of the B c meson and a new kind of parametrization for extrapolating the form factors which takes into account the recent lattice QCD results.We find the following main results:(a)the PQCD predictions of the branching ratios of theBc→(ηc,J/ψ)l■decays are smaller by about 5%-16%when the lattice results are taken into account in the extrapolation of the relevant form factors;(b)the PQCD predictions of the ratio Rηc,RJ/ψand of the longitudinal polarization PτareRηc=0.34±0.01,RJ/ψ=0.28±0.01,Pτ(ηc)=0.37±0.01and Pτ(J/ψ)=-0.55±0.01;and(c)after including the lattice results,the theoretical predictions slightly change:Rηc=0.31±0.01,RJ/ψ=0.27±0.01,Pτ(ηc)=0.36±0.01andPτ(J/ψ)=-0.53±0.01.The theoretical predictions of RJ/ψagree with the measurements within the errors.The other predictions could be tested by the LHCb experiment in the near future.
文摘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.
基金Supported by DGI and FEDER funds,under contracts FIS2008-01143/FIS,FIS2006-03438,FPA2007-65748,CSD2007- 00042Junta de Castilla y León under contracts SA016A07 and GR12+2 种基金Generalitat Valenciana under contract PROM- ETEO/20090090the EU HadronPhysics2 project,grant agreement n.227431supported by PIE- CSIC 200850I238 during his stay at IFIC
文摘We analyze the effects of hyperfine mixing in b → c semileptonic decays of doubly heavy baryons.We qualitatively confirm the results by W.Roberts and M.Pervin in Int.J.Mod.Phys.A,2009,24： 2401– 2413,finding that mixing has a great impact on those transitions.However,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.
基金supported in part by the National Natural Science Foundation of China under Contracts No. 11875168 and No. 11375088。
文摘In this work we study the semileptonic decay of Bs^-0→φI^+I^-(l=e,μ,τ) with the QCD sum rule method. We calculate the Bs^-0→φ ftranslation form factors relevant to this semileptonic decay, then the branching ratios of Bs^-0→φI^+I^-(l=e,μ,τ)decays are calculated with the form factors obtained here. Our result for the branching ratio of Bs^-0→φμ^+μ^- agree very well with the recent experimental data. For the unmeasured decay modes such as Bs^-0→φe^+e^- and Bs^-0→τ^+τ……-, we give theoretical predictions.
基金Supported by National Natural Science Foundation of China(11175051)
文摘The singlet-triplet mixing of 1P1-3P1 is studied via calculating the branching ratios of semileptonic decay Bs→Ds1lν and B→D1lν 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. And the non-perturbative QCD effects are taken care of in the overlapping integral over the relativistic wave functions of the initial and nial states.
基金Supported by National Natural Science Foundation under Grant Nos.11075053,11375063the Fundamental Research Funds for the Central Universities
文摘In this article, we calculate the B＊→ηc form-factors with the three-point QCD sum rules, then study the semileptonic decays B＊→ηclυl. The tiny decay widths may be observed experimentally in the future at the LHCb, while the B＊→ηc form-factors can be taken as basic input parameters in other phenomenologieal analysis.
基金Supported by DGI and FEDER funds (FIS2006-03438,FIS2008-01143/FIS)PIE-CSIC (200850I238)
文摘We study the semileptonic decays of the lowest-lying bc baryons to the lowest-lying cc baryons （Ξ （＊） bc → Ξ （＊） cc and Ω （ ＊） bc → Ω （＊） cc ）,in the limit m b,m c Λ QCD and close to the zero recoil point.The separate heavy quark spin symmetries make it possible to describe all these decays using a single form factor.We also show how these constraints can be used to test the validity of different quark model calculations.bb to bc baryon decays are also discussed.
基金Supported in part by the National Natural Science Foundation of China(12265010,12265009)the Project of Guizhou Provincial Department of Science and Technology(ZK[2021]024,ZK[2023]142)。
文摘In this paper,we investigate the charmed meson rare decay process D^(+)→π^(+)v■using an approach based on QCD sum rules.First,the pion twist-2,3 distribution amplitude(DA)moments<ξ_(2)^(n);|μand<ξ3;π(p,σ),n>|μ,are calculated up to the tenth and fourth orders,respectively,in the QCD sum rules according to the background field theory.After constructing the light-cone harmonic oscillator model for the pion twist-2,3 D As,we obtain their behaviors by matching the calculatedξ-moments.Then,the D→πtransition form factors(TFFs)are calculated using an approach based on QCD light-cone sum rules.The vector form factor at the large recoil region is f_(+)^(D)→^(π)(0)=0.627_(-0.080)^(+0.120).Using the rapidly converging simplified series expansion of z(q^(2),t),we present the TFFs and corresponding angular coefficients in the whole squared momentum transfer physical region.Based on nonstandard neutrino interactions,the■^(0)→π^(+)e■_(e)decay can be related to the■^(0)→π^(+)e■_(e)decay indirectly.Thus,we first describe the semileptonic decay process■^(0)→π^(+)e■_(e),differential decay widths,and branching fraction with B(■^(0)→π^(+)e■_(e))=0.308_(-0.066)^(+0.155)×10^(2).The■^(0)→π^(+)e■_(e)differential/total predictions for forward-backward asymmetry,q^(2)-differential flat terms,and lepton polarization asymmetry are also reported.The prediction for the D^(+)→π^(+)v■branching fraction isB(D^(+)→π^(+)v■)=1.85_(-0.46)+^(0.93)×10^(-8).
基金Supported in part by the National Natural Science Foundation of China(12265009,12265010)the Project of Guizhou Provincial Department of Science and Technology(ZK[2021]024,ZK[2023]142)+1 种基金the Project of Guizhou Provincial Department of Education(KY[2021]030)the Chongqing Graduate Research and Innovation Foundation(ydstd1912)。
文摘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 SM.Usually,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→Dtve.Therefore,it is important to obtain more reasonable and accurate behaviors for these DAs.Motivated by our previous work[Phys.Rev.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 values.The 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.
