In this short review,we present the current status about the theoretical and experimental studies for some important semileptonic decays of B=Bsmesons.We firstly gave a brief introduction for the experimental measurem...In this short review,we present the current status about the theoretical and experimental studies for some important semileptonic decays of B=Bsmesons.We firstly gave a brief introduction for the experimental measurements for B=Bs!Peltl;l ml;m mT decays,the BaBar’s ReDT and ReD T anomaly,the P05deviation for B0!K 0ltl decay.We then made a careful discussion about the evaluations for the relevant form factors in the light-cone QCD sum rule,the heavy quark effective theory,and the perturbative QCD factorization approach.By using the form factors calculated in the perturbative(pQCD)approach,we then calculate and show the pQCD predictions for the decay rates of many semileptonic decays of B=Bsmesons.We also made careful phenomenological analysis for these pQCD predictions and found,in general,the following points:(a)For all the considered B=Bssemileptonic decays,the next-to-leading order pQCD predictions for their decay rates agree well with the data and those from other different theoretical methods;(b)For ReDT and ReD T,the pQCD predictions agree very well with the data,the BaBar’s anomaly of ReDe TT are therefore explained successfully in the standard model by employing the pQCD approach;and(c)We defined several new ratios Rl;s Dand Rl;s Ds,they may be more sensitive to the QCD dynamics which controls the B=Bs!eDe T;De T sT transitions than the old ratios,we therefore strongly suggest LHCb and the forthcoming Super-B experiments to measure these new ratios.展开更多
Along with the running of Large Hadron Collider(LHC)located at CERN in November 2009,a large number of data samples of Bc meson have been collected and some hadronic Bc decay modes have been measured by the LHC experi...Along with the running of Large Hadron Collider(LHC)located at CERN in November 2009,a large number of data samples of Bc meson have been collected and some hadronic Bc decay modes have been measured by the LHC experiments.In view of the special and important roles of Bc meson decays playing in the heavy flavor sector,we here give a short review on the status of two body hadronic decays Bc!M1M2at both experimental and theoretical aspects.For the theoretical progresses,specifically,we will show lots of theoretical studies on two body hadronic Bcdecays involving pseudoscalar,vector,scalar,axial-vector,even tensor meson(s)in the final states by employing the perturbative QCD(pQCD)factorization approach.We will present a general analysis about the twobody hadronic decays of the heavy Bc meson and also provide some expectations for the future developments.展开更多
In this paper,we study the B→D^(*) l-l -ι semileptonic decays and calculate the branching ratios B(B→D^(*) l-l -ι) and the ratios R(D^(*)) and R_D^( l,s) by employing the perturbative QCD(pQCD)factorization appro...In this paper,we study the B→D^(*) l-l -ι semileptonic decays and calculate the branching ratios B(B→D^(*) l-l -ι) and the ratios R(D^(*)) and R_D^( l,s) by employing the perturbative QCD(pQCD)factorization approach.We find that(a)for R(D)and R(D*)ratios,the pQCD predictions are R(D)=0.430-0.026?0.021,R(D*)=0.301±0.013 and agree well with BaBar’s measurements of ReD e?T T;(b)for the newly defined R_D^1 and R_D^s ratios,the pQCD predictions are R_D^l=0.450-0.051+0.064 and R_D^s=0.642-0.070+0.081,which may be more sensitive to the QCD dynamics of the considered semileptonic decays than R(D^(*)) and should be tested by experimental measurements.展开更多
The new particles predicted by the littlest Higgs model with T-parity (called LHT model) can induce the lepton flavor violation (LFV) couplings at the one-loop level,which can add contributions to some LFV processes.T...The new particles predicted by the littlest Higgs model with T-parity (called LHT model) can induce the lepton flavor violation (LFV) couplings at the one-loop level,which can add contributions to some LFV processes.Taking into account the constraints of the experimental data on the relevant free parameters,we calculate the branching ratios of the LFV decay processes Z → l ˉl and τ-→μ-P 1 P 2 with P 1 P 2 = π + π-,K + K-,and K0 ˉK 0 in the context of this new physics model.We find that the LHT model can indeed make significant contributions to some of these LFV decay processes.The Z factory option for the future high energy e + e-collider experiments will give severe constraints on the LHT model.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
We present a systematic calculation on the α-decay branching ratios to excited-states of an even-even α-decay chain ^242Cm → ^238Pu → ^234U → ^230Th → ^226Rn by the improved barrier penetration approach. The c...We present a systematic calculation on the α-decay branching ratios to excited-states of an even-even α-decay chain ^242Cm → ^238Pu → ^234U → ^230Th → ^226Rn by the improved barrier penetration approach. The changes of the parities between the parent nuclei and the daughter nuclei are properly taken into account. The theoretical values are compared with the available experimental data and the deviation between them is within a factor of 5 in most cases.展开更多
FCNC processes offer important tools to test the Standard Model（SM）and to search for possible new physics.In this work,we investigate the s→dvv rare hyperon decays in SM and beyond.We find that in SM the branching ...FCNC processes offer important tools to test the Standard Model（SM）and to search for possible new physics.In this work,we investigate the s→dvv rare hyperon decays in SM and beyond.We find that in SM the branching ratios for these rare hyperon decays range from 10-14 to 10-11.When all the errors in the form factors are included,we find that the final branching ratios for most decay modes have an uncertainty of about 5% to 10%.After taking into account the contribution from new physics,the generalized SUSY extension of SM and the minimal 331 model,the decay widths for these channels can be enhanced by a factor of 2～7.展开更多
β-decay half-life is a key quantity for nuclear structure and nucleosynthesis studies.There exist large uncertainties in the contributions of allowed and forbidden transitions to the totalβ-decay life,which limits t...β-decay half-life is a key quantity for nuclear structure and nucleosynthesis studies.There exist large uncertainties in the contributions of allowed and forbidden transitions to the totalβ-decay life,which limits the resolution of the predictedβ-decay half-life.We systematically study the contribution of the first forbidden(FF)transitions to theβ--decay half-life,and quantify it with a formula based on simple physics considerations.We also propose a new formula for calculation of theβ--decay half-life that includes the FF contribution.It is shown that the inclusion of the contribution of FF transitions significantly improves the precision of calculations of theβ--decay half-life.By fitting of the RQRPA results for neutron-rich Z=47,57 isotopes and N=80,94 isotones,the formula for the contribution of the FF transitions gives similar results as the RQRPA calculations.However,because of limited experimental data for the branching ratios of unstable nuclei,the fit parameters are not fully constrained.Therefore,the proposed formula for theβ--decay half-life is more suitable for calculations of half-lives than of the FF contributions.The formula could be used to predict theβ?-decay half-life in nuclear structure studies as well as nucleosynthesis calculations in stars.展开更多
基金supported by the National Natural Science Foundation of China (11235005 and 10975074)
文摘In this short review,we present the current status about the theoretical and experimental studies for some important semileptonic decays of B=Bsmesons.We firstly gave a brief introduction for the experimental measurements for B=Bs!Peltl;l ml;m mT decays,the BaBar’s ReDT and ReD T anomaly,the P05deviation for B0!K 0ltl decay.We then made a careful discussion about the evaluations for the relevant form factors in the light-cone QCD sum rule,the heavy quark effective theory,and the perturbative QCD factorization approach.By using the form factors calculated in the perturbative(pQCD)approach,we then calculate and show the pQCD predictions for the decay rates of many semileptonic decays of B=Bsmesons.We also made careful phenomenological analysis for these pQCD predictions and found,in general,the following points:(a)For all the considered B=Bssemileptonic decays,the next-to-leading order pQCD predictions for their decay rates agree well with the data and those from other different theoretical methods;(b)For ReDT and ReD T,the pQCD predictions agree very well with the data,the BaBar’s anomaly of ReDe TT are therefore explained successfully in the standard model by employing the pQCD approach;and(c)We defined several new ratios Rl;s Dand Rl;s Ds,they may be more sensitive to the QCD dynamics which controls the B=Bs!eDe T;De T sT transitions than the old ratios,we therefore strongly suggest LHCb and the forthcoming Super-B experiments to measure these new ratios.
基金supported by the National Natural Science Foundation of China (11205072,10975074 and 11235005)
文摘Along with the running of Large Hadron Collider(LHC)located at CERN in November 2009,a large number of data samples of Bc meson have been collected and some hadronic Bc decay modes have been measured by the LHC experiments.In view of the special and important roles of Bc meson decays playing in the heavy flavor sector,we here give a short review on the status of two body hadronic decays Bc!M1M2at both experimental and theoretical aspects.For the theoretical progresses,specifically,we will show lots of theoretical studies on two body hadronic Bcdecays involving pseudoscalar,vector,scalar,axial-vector,even tensor meson(s)in the final states by employing the perturbative QCD(pQCD)factorization approach.We will present a general analysis about the twobody hadronic decays of the heavy Bc meson and also provide some expectations for the future developments.
基金supported by the National Natural Science Foundation of China(10975074 and 11235005)
文摘In this paper,we study the B→D^(*) l-l -ι semileptonic decays and calculate the branching ratios B(B→D^(*) l-l -ι) and the ratios R(D^(*)) and R_D^( l,s) by employing the perturbative QCD(pQCD)factorization approach.We find that(a)for R(D)and R(D*)ratios,the pQCD predictions are R(D)=0.430-0.026?0.021,R(D*)=0.301±0.013 and agree well with BaBar’s measurements of ReD e?T T;(b)for the newly defined R_D^1 and R_D^s ratios,the pQCD predictions are R_D^l=0.450-0.051+0.064 and R_D^s=0.642-0.070+0.081,which may be more sensitive to the QCD dynamics of the considered semileptonic decays than R(D^(*)) and should be tested by experimental measurements.
基金supported in part by the National Natural Science Foundation of China (Grant No.10975067)Specialized Research Fund for the Doctoral Program of Higher Education (SRFDP) (Grant No.200801650002)+1 种基金the Natural Science Foundation of the Liaoning Scientific Committee (Grant No.20082148)the Foundation of Liaoning Educational Committee (Grant No.2007T086)
文摘The new particles predicted by the littlest Higgs model with T-parity (called LHT model) can induce the lepton flavor violation (LFV) couplings at the one-loop level,which can add contributions to some LFV processes.Taking into account the constraints of the experimental data on the relevant free parameters,we calculate the branching ratios of the LFV decay processes Z → l ˉl and τ-→μ-P 1 P 2 with P 1 P 2 = π + π-,K + K-,and K0 ˉK 0 in the context of this new physics model.We find that the LHT model can indeed make significant contributions to some of these LFV decay processes.The Z factory option for the future high energy e + e-collider experiments will give severe constraints on the LHT model.
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.
基金Supported by National Natural Science Foundation of China (10535010, 10805026, 10775068, 10735010)Major State Basic Research Development Program (2007CB815004)Doctoral Fund of Ministry of Education of China (20070284016)
文摘We present a systematic calculation on the α-decay branching ratios to excited-states of an even-even α-decay chain ^242Cm → ^238Pu → ^234U → ^230Th → ^226Rn by the improved barrier penetration approach. The changes of the parities between the parent nuclei and the daughter nuclei are properly taken into account. The theoretical values are compared with the available experimental data and the deviation between them is within a factor of 5 in most cases.
基金Supported in part by National Natural Science Foundation of China(11575110,11735010,11911530088)Natural Science Foundation of Shanghai(15DZ2272100)and Key Laboratory for Particle Physics,Astrophysics and Cosmology,Ministry of Education
文摘FCNC processes offer important tools to test the Standard Model（SM）and to search for possible new physics.In this work,we investigate the s→dvv rare hyperon decays in SM and beyond.We find that in SM the branching ratios for these rare hyperon decays range from 10-14 to 10-11.When all the errors in the form factors are included,we find that the final branching ratios for most decay modes have an uncertainty of about 5% to 10%.After taking into account the contribution from new physics,the generalized SUSY extension of SM and the minimal 331 model,the decay widths for these channels can be enhanced by a factor of 2～7.
基金Supported by National Natural Science Foundation of China(11565010,U1731218,11761161001)the Science and Technology Fund of Guizhou Province((2015)4015,(2016)-4008))the Science and Technology Development Fund(FDCT) of Macao(020/2014/A1,008/2017/AFJ,119/2017/A3)
文摘β-decay half-life is a key quantity for nuclear structure and nucleosynthesis studies.There exist large uncertainties in the contributions of allowed and forbidden transitions to the totalβ-decay life,which limits the resolution of the predictedβ-decay half-life.We systematically study the contribution of the first forbidden(FF)transitions to theβ--decay half-life,and quantify it with a formula based on simple physics considerations.We also propose a new formula for calculation of theβ--decay half-life that includes the FF contribution.It is shown that the inclusion of the contribution of FF transitions significantly improves the precision of calculations of theβ--decay half-life.By fitting of the RQRPA results for neutron-rich Z=47,57 isotopes and N=80,94 isotones,the formula for the contribution of the FF transitions gives similar results as the RQRPA calculations.However,because of limited experimental data for the branching ratios of unstable nuclei,the fit parameters are not fully constrained.Therefore,the proposed formula for theβ--decay half-life is more suitable for calculations of half-lives than of the FF contributions.The formula could be used to predict theβ?-decay half-life in nuclear structure studies as well as nucleosynthesis calculations in stars.
