Motivated by recently observed anomalously large dimuon charge asymmetry in neutral B decays reported by the D0 collaboration,we study the effects of a family of non-universal Z′bosons for possible solutions.The fitt...Motivated by recently observed anomalously large dimuon charge asymmetry in neutral B decays reported by the D0 collaboration,we study the effects of a family of non-universal Z′bosons for possible solutions.The fitting results for the Z′parameters are presented under the constraints from the D0 result for asls and UTfit results for CBs andφBs in two limiting scenarios for left−and right-handed b-s-Z′couplings.We find the couplings BsbL and BsbR are rigorously bounded but not excluded,which means that the anomalies in the Bs−Bs system could be moderated simultaneously within a non-universal Z′model.Numerically,a new weak phaseφLs∼−60°(−80°)in scenario I or∼30°(10°)in scenario II is crucial to moderate the large dimuon charge asymmetry.展开更多
Studies of e^+e~→D_s^+■^((*)0)K^-and the P-wave charmed-strange mesons are performed based on an e^+e^-collision data sample corresponding to an integrated luminosity of 567 pb^(-1) collected with the BESIII detecto...Studies of e^+e~→D_s^+■^((*)0)K^-and the P-wave charmed-strange mesons are performed based on an e^+e^-collision data sample corresponding to an integrated luminosity of 567 pb^(-1) collected with the BESIII detector at s^(1/2)=4.600 GeV. The processes of e^+e^-→D_s^+■^(*0)K^- and D_s^+■~0K^- are observed for the first time and are found to be dominated by the modes D_s^+D_(s1)(2536)^-and D_s^+D_(s2)~*(2573)^-, respectively. The Born cross sections are measured to be σ~B(e^+e^-→D_s^+■^(*0)K^-) =(10.1±2.3±0.8) pb and σ~B(e^+e^-→D_s^+■~0K^-) =(19.4±2.3± 1.6) pb, and the products of Born cross section and the decay branching fraction are measured to be σ~B(e^+e^-→D_s^+D_(s1)(2536)^-+c.c.)·B(D_(s1)(2536)^-→■^(*0)K^-)=(7.5±1.8±0.7) pb and σ~B(e^+e^-→D_s^+D_(s2)~*(2573)^-+ c.c.)·B(D_(s2)~*(2573)^-→■~0 K^-)=(19.7 ± 2.9 ±2.0) pb. For the D_(s1)(2536)^-and D_(s2)~*(2573)^-mesons, the masses and widths are measured to be M(D_(s1)(2536)^-)=(2537.7±0.5 ±3.1) MeV/c2, Γ(D_(s1)(2536)^-) =(1.7 ±1.2 ±0.6)MeV, and M(D_(s2)~*(2573)^-)=(2570.7±2.0 ±1.7) MeV/c^2, Γ(D_(s2)~*(2573)^-)=(17.2 ±3.6 ±1.1) MeV. The spin-parity of the D_(s2)~*(2573)^-meson is determined to be J^p= 2^+. In addition, the processes e^+e^-→D_s^+■^((*)0)K^-are searched for using the data samples taken at four(two) center-of-mass energies between 4.416(4.527) and 4.575 GeV, and upper limits at the 90% confidence level on the cross sections are determined.展开更多
Recently,the CDF Collaboration has measured the branching fraction and time-integrated direct CP asymmetry of Bs → K-π＋ decay.The branching ratio is lower than the previous predictions based on QCD factorization.Th...Recently,the CDF Collaboration has measured the branching fraction and time-integrated direct CP asymmetry of Bs → K-π＋ decay.The branching ratio is lower than the previous predictions based on QCD factorization.The experimental results favor a large CP asymmetry in Bs → K-π＋ decay while the standard model prediction is very small.We compute the supersymmetry contributions to Bs → K-π＋ decay using the mass insertion method,and find that the LR and RL mass insertions could suppress this branching ratio and increase this direct CP asymmetry well in line with the experimental data.展开更多
Motivated by the first measurement on B（Bs→ Ф μ^＋ μ^-by the CDF Collaboration, we study the supersymmetric effects in semi-leptonic Bs→ Ф μ^＋ μ^-ecay. In our evaluations, we analyze the dependences of the d...Motivated by the first measurement on B（Bs→ Ф μ^＋ μ^-by the CDF Collaboration, we study the supersymmetric effects in semi-leptonic Bs→ Ф μ^＋ μ^-ecay. In our evaluations, we analyze the dependences of the dimuon invariant mass spectrum and the forward-backward asymmetry on relevant supersymmetric couplings in the MSSM with and without R-parity. The analyses show that the new experimental upper limits of B（Bs→ Ф μ^＋ μ^-from the LHCb Collaboration could further improve the bounds on sneutrino exchange couplings and （δ^u LL）23 as well as （δ^d LL,RR）23 mass insertion couplings. In addition, within the allowed ranges of relevant couplings under the constraints from B（Bs→ Ф μ^＋ μ^- B（B → K^（＊） μ^＋ μ^-and B（Bs → μ^＋ μ^-, the dimuon forward-backward asymmetry and the differential dimuon forward-backward asymmetry of Bs→Ф μ^＋ μ^-re highly sensitive to the squark exchange contribution and the （ LL）23 mass insertion contribution. The results obtained in this work will be very useful in searching for supersymmetric signals at the LHC.展开更多
基金by the National Natural Science Foundation of China under Grant Nos 11075059 and 11047145the Project of Basic and Advanced Technology Research of Henan Province under Grant No.112300410021Startup Foundation for Doctor of Henan Normal University under Grant No 1006.
文摘Motivated by recently observed anomalously large dimuon charge asymmetry in neutral B decays reported by the D0 collaboration,we study the effects of a family of non-universal Z′bosons for possible solutions.The fitting results for the Z′parameters are presented under the constraints from the D0 result for asls and UTfit results for CBs andφBs in two limiting scenarios for left−and right-handed b-s-Z′couplings.We find the couplings BsbL and BsbR are rigorously bounded but not excluded,which means that the anomalies in the Bs−Bs system could be moderated simultaneously within a non-universal Z′model.Numerically,a new weak phaseφLs∼−60°(−80°)in scenario I or∼30°(10°)in scenario II is crucial to moderate the large dimuon charge asymmetry.
基金Supported in part by National Key Basic Research Program of China(2015CB856700)National Natural Science Foundation of China(NSFC)(11335008,11425524,11625523,11635010,11735014)+9 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Program,the CAS Center for Excellence in Particle Physics(CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1532257,U1532258,U1732263)CAS Key Research Program of Frontier Sciences(QYZDJ-SSW-SLH003,QYZDJ-SSW-SLH040)100 Talents Program of CASINPAC,Shanghai Key Laboratory for Particle Physics and Cosmology,German Research Foundation DFG under Contracts Nos.Collaborative Research Center CRC 1044,FOR 2359Istituto Nazionale di Fisica Nucleare,Italy,Koninklijke Nederlandse Akademie van Wetenschappen(KNAW)(530-4CDP03)Ministry of Development of Turkey(DPT2006K-120470)National Science and Technology fund,The Swedish Research CouncilU.S.Department of Energy(DE-FG02-05ER41374,DE-SC-0010118,DE-SC-0010504,DE-SC-0012069),University of Groningen(RuG)the Helmholtzzentrum fuer Schwerionenforschung GmbH(GSI),Darmstadt
文摘Studies of e^+e~→D_s^+■^((*)0)K^-and the P-wave charmed-strange mesons are performed based on an e^+e^-collision data sample corresponding to an integrated luminosity of 567 pb^(-1) collected with the BESIII detector at s^(1/2)=4.600 GeV. The processes of e^+e^-→D_s^+■^(*0)K^- and D_s^+■~0K^- are observed for the first time and are found to be dominated by the modes D_s^+D_(s1)(2536)^-and D_s^+D_(s2)~*(2573)^-, respectively. The Born cross sections are measured to be σ~B(e^+e^-→D_s^+■^(*0)K^-) =(10.1±2.3±0.8) pb and σ~B(e^+e^-→D_s^+■~0K^-) =(19.4±2.3± 1.6) pb, and the products of Born cross section and the decay branching fraction are measured to be σ~B(e^+e^-→D_s^+D_(s1)(2536)^-+c.c.)·B(D_(s1)(2536)^-→■^(*0)K^-)=(7.5±1.8±0.7) pb and σ~B(e^+e^-→D_s^+D_(s2)~*(2573)^-+ c.c.)·B(D_(s2)~*(2573)^-→■~0 K^-)=(19.7 ± 2.9 ±2.0) pb. For the D_(s1)(2536)^-and D_(s2)~*(2573)^-mesons, the masses and widths are measured to be M(D_(s1)(2536)^-)=(2537.7±0.5 ±3.1) MeV/c2, Γ(D_(s1)(2536)^-) =(1.7 ±1.2 ±0.6)MeV, and M(D_(s2)~*(2573)^-)=(2570.7±2.0 ±1.7) MeV/c^2, Γ(D_(s2)~*(2573)^-)=(17.2 ±3.6 ±1.1) MeV. The spin-parity of the D_(s2)~*(2573)^-meson is determined to be J^p= 2^+. In addition, the processes e^+e^-→D_s^+■^((*)0)K^-are searched for using the data samples taken at four(two) center-of-mass energies between 4.416(4.527) and 4.575 GeV, and upper limits at the 90% confidence level on the cross sections are determined.
基金Supported by National Natural Science Foundation of China (10675039, 10735080)
文摘Recently,the CDF Collaboration has measured the branching fraction and time-integrated direct CP asymmetry of Bs → K-π＋ decay.The branching ratio is lower than the previous predictions based on QCD factorization.The experimental results favor a large CP asymmetry in Bs → K-π＋ decay while the standard model prediction is very small.We compute the supersymmetry contributions to Bs → K-π＋ decay using the mass insertion method,and find that the LR and RL mass insertions could suppress this branching ratio and increase this direct CP asymmetry well in line with the experimental data.
基金Supported by National Natural Science Foundation of China(11105115,11147136),Joint Funds of the National Natural Science Foundation of China(U1204113)Project of Basic and Advanced,Technology Research of Henan Province(112300410021)Natural Research Project of Henan Province(2011A140023)
文摘Motivated by the first measurement on B（Bs→ Ф μ^＋ μ^-by the CDF Collaboration, we study the supersymmetric effects in semi-leptonic Bs→ Ф μ^＋ μ^-ecay. In our evaluations, we analyze the dependences of the dimuon invariant mass spectrum and the forward-backward asymmetry on relevant supersymmetric couplings in the MSSM with and without R-parity. The analyses show that the new experimental upper limits of B（Bs→ Ф μ^＋ μ^-from the LHCb Collaboration could further improve the bounds on sneutrino exchange couplings and （δ^u LL）23 as well as （δ^d LL,RR）23 mass insertion couplings. In addition, within the allowed ranges of relevant couplings under the constraints from B（Bs→ Ф μ^＋ μ^- B（B → K^（＊） μ^＋ μ^-and B（Bs → μ^＋ μ^-, the dimuon forward-backward asymmetry and the differential dimuon forward-backward asymmetry of Bs→Ф μ^＋ μ^-re highly sensitive to the squark exchange contribution and the （ LL）23 mass insertion contribution. The results obtained in this work will be very useful in searching for supersymmetric signals at the LHC.
