The flavor-changing neutral current (FCNC) problem at tree-level is a very critical defect of the two Higgs doublet extension of standard model (SM). In this article, a two-Higgs-doublet model (2HDM) in which such def...The flavor-changing neutral current (FCNC) problem at tree-level is a very critical defect of the two Higgs doublet extension of standard model (SM). In this article, a two-Higgs-doublet model (2HDM) in which such defects do not exist at all is to be demonstrated. The general pattern of matrix pairs which can be diagonalized simul-taneously by a same unitary transformation is proposed without extra constraints like symmetries or zeros in M matrices. Only an assumption of the hermiticity of mass matrices is employed in the derivation. With this assumption, number of parameters in the mass matrix of a specific fermion type is reduced from eighteen down to five. Eigenvalues and eigenvectors are analytically derived and it is surprising that unitary transformation matrix thus derived depends on only two parameters. It is a very general and elegant way to solve the tree-level FCNC problem radically and it includes previous similar models as special cases with specific parameter values.展开更多
In this study,we perform a detailed analysis on the same-sign dilepton signature in the inert doublet model.Focusing on the low dark matter mass region,we randomly scan the corresponding parameter space.Viable samples...In this study,we perform a detailed analysis on the same-sign dilepton signature in the inert doublet model.Focusing on the low dark matter mass region,we randomly scan the corresponding parameter space.Viable samples allowed by various constraints are obtained,and among them are twenty benchmark points that are selected for further study on collider signature.At hadron colliders,the same-sign dilepton signature is produced via pp→W^(±+)+W^(±+)jj→H^(±)H^(±)jj with the leptonic decay mode H^(±)→HW^(±)(→l^(±)ν),where H represents the dark matter candidate.We investigate the testability of this signal at the high-luminosity LHC(HL-LHC)and the proposed 27 TeV high-energy LHC(HE-LHC).According to our simulation,the HL-LHC with L=3 ab^(-1)can barely probe this signal.Meanwhile,for the HE-LHC with L=15ab^(-1),it is promising to obtain a 5σsignificance when 250 GeV≤m__(H)^(±)-m_(H)≤300 GeV with dark matter mass m_(H)60 or 71 GeV.展开更多
We analyze the radiative leptonic Bc decay Bc^-→τ^vτ^-γ in the Standard Model and the two- Higgs-doublet model using the non-relativistic constituent quark model. The results confirm that this channel is experimen...We analyze the radiative leptonic Bc decay Bc^-→τ^vτ^-γ in the Standard Model and the two- Higgs-doublet model using the non-relativistic constituent quark model. The results confirm that this channel is experimentally promising in view of the large number of Bc mesons which are expected to be produced at future hadron facilities. We also find that this decay is sensitive to the parameters of the two-Higgs-doublet model, and it can be tested in future experiments.展开更多
In the framework of T2HDM, we calculated the new physics contributions involving neutral Higgs bosons to the branching ratios of ^-Bs,d^0→e^＋e^-（e= e,μ） decays. Comparing the theoretical predictions with the expe...In the framework of T2HDM, we calculated the new physics contributions involving neutral Higgs bosons to the branching ratios of ^-Bs,d^0→e^＋e^-（e= e,μ） decays. Comparing the theoretical predictions with the experimental upper-limits, we found that （a） The data of Br（^-Bs,d^0→e^＋e^-） give the upper bound on tanβ： tanβ≤22, while Br（^-Bs^0→e^＋e^-） give tanβ≤12 for fixed δ = 0^0, mH＋ = 350 CeV, mH^0 = 160 GeV, mh^0 = 115 GeV and mA^0 = 120 GeV; （b） A light neutral Higgs boson mass mho （mA^0） less than 50 GeV （120 GeV） is excluded by the data of branching ratios for ^-Bs,d^0→e^＋e^-（e = μ） decays with tanβ= 10; （c） The bounds on mh^0 and tanβ, or mA^0 and tanβ are strongly correlated： a smaller （larger） tanβ means a lighter （heavier） neutral Higgs boson.展开更多
We consider a five-electron system in the Hubbard model with a coupling between nearest-neighbors. The structure of essential spectrum and discrete spectrum of the systems in the third and fourth doublet states in a &...We consider a five-electron system in the Hubbard model with a coupling between nearest-neighbors. The structure of essential spectrum and discrete spectrum of the systems in the third and fourth doublet states in a <em>v</em>-dimensional lattice is investigated. We prove that the essential spectrum of the system in a third doublet state consists is the union of at most four segments, and discrete spectrum of the system is empty. We show that the essential spectrum of the system in a fourth doublet state consists of the union of at most seven segments, and discrete spectrum of the system consists of no more than one point.展开更多
We consider a three-electron system in the Impurity Hubbard model with a coupling between nearest-neighbors. Our research aim consists of studying the structure of essential spectrum and discrete spectra of the energy...We consider a three-electron system in the Impurity Hubbard model with a coupling between nearest-neighbors. Our research aim consists of studying the structure of essential spectrum and discrete spectra of the energy operator of three-electron systems in the impurity Hubbard model in the quartet state of the system in a <em>v</em>-dimensional lattice. We have reduced the study of the spectrum of the three-electron quartet state operator in the impurity Hubbard model to the study of the spectrum of a simpler operator. We proved the essential spectra of the three-electron systems in the Impurity Hubbard model in the quartet state is the union of no more than six segments, and the discrete spectrum of the system is consists of no more than four eigenvalues.展开更多
文摘The flavor-changing neutral current (FCNC) problem at tree-level is a very critical defect of the two Higgs doublet extension of standard model (SM). In this article, a two-Higgs-doublet model (2HDM) in which such defects do not exist at all is to be demonstrated. The general pattern of matrix pairs which can be diagonalized simul-taneously by a same unitary transformation is proposed without extra constraints like symmetries or zeros in M matrices. Only an assumption of the hermiticity of mass matrices is employed in the derivation. With this assumption, number of parameters in the mass matrix of a specific fermion type is reduced from eighteen down to five. Eigenvalues and eigenvectors are analytically derived and it is surprising that unitary transformation matrix thus derived depends on only two parameters. It is a very general and elegant way to solve the tree-level FCNC problem radically and it includes previous similar models as special cases with specific parameter values.
基金Supported by the National Natural Science Foundation of China(11805081)Natural Science Foundation of Shandong Province(ZR2019QA021,ZR2018MA047)。
文摘In this study,we perform a detailed analysis on the same-sign dilepton signature in the inert doublet model.Focusing on the low dark matter mass region,we randomly scan the corresponding parameter space.Viable samples allowed by various constraints are obtained,and among them are twenty benchmark points that are selected for further study on collider signature.At hadron colliders,the same-sign dilepton signature is produced via pp→W^(±+)+W^(±+)jj→H^(±)H^(±)jj with the leptonic decay mode H^(±)→HW^(±)(→l^(±)ν),where H represents the dark matter candidate.We investigate the testability of this signal at the high-luminosity LHC(HL-LHC)and the proposed 27 TeV high-energy LHC(HE-LHC).According to our simulation,the HL-LHC with L=3 ab^(-1)can barely probe this signal.Meanwhile,for the HE-LHC with L=15ab^(-1),it is promising to obtain a 5σsignificance when 250 GeV≤m__(H)^(±)-m_(H)≤300 GeV with dark matter mass m_(H)60 or 71 GeV.
基金Supported by National Natural Science Foundation of China (10675022,10975018)
文摘We analyze the radiative leptonic Bc decay Bc^-→τ^vτ^-γ in the Standard Model and the two- Higgs-doublet model using the non-relativistic constituent quark model. The results confirm that this channel is experimentally promising in view of the large number of Bc mesons which are expected to be produced at future hadron facilities. We also find that this decay is sensitive to the parameters of the two-Higgs-doublet model, and it can be tested in future experiments.
基金Supported by National Natural Science Foundation of CHina (10947020)Fund of He'nan Educational Committee for Youth Backbone Scholars in Colleges and UniversitiesSpecial Study Foundation of Nanyang Normal University (nynu200750)
文摘In the framework of T2HDM, we calculated the new physics contributions involving neutral Higgs bosons to the branching ratios of ^-Bs,d^0→e^＋e^-（e= e,μ） decays. Comparing the theoretical predictions with the experimental upper-limits, we found that （a） The data of Br（^-Bs,d^0→e^＋e^-） give the upper bound on tanβ： tanβ≤22, while Br（^-Bs^0→e^＋e^-） give tanβ≤12 for fixed δ = 0^0, mH＋ = 350 CeV, mH^0 = 160 GeV, mh^0 = 115 GeV and mA^0 = 120 GeV; （b） A light neutral Higgs boson mass mho （mA^0） less than 50 GeV （120 GeV） is excluded by the data of branching ratios for ^-Bs,d^0→e^＋e^-（e = μ） decays with tanβ= 10; （c） The bounds on mh^0 and tanβ, or mA^0 and tanβ are strongly correlated： a smaller （larger） tanβ means a lighter （heavier） neutral Higgs boson.
文摘We consider a five-electron system in the Hubbard model with a coupling between nearest-neighbors. The structure of essential spectrum and discrete spectrum of the systems in the third and fourth doublet states in a <em>v</em>-dimensional lattice is investigated. We prove that the essential spectrum of the system in a third doublet state consists is the union of at most four segments, and discrete spectrum of the system is empty. We show that the essential spectrum of the system in a fourth doublet state consists of the union of at most seven segments, and discrete spectrum of the system consists of no more than one point.
文摘We consider a three-electron system in the Impurity Hubbard model with a coupling between nearest-neighbors. Our research aim consists of studying the structure of essential spectrum and discrete spectra of the energy operator of three-electron systems in the impurity Hubbard model in the quartet state of the system in a <em>v</em>-dimensional lattice. We have reduced the study of the spectrum of the three-electron quartet state operator in the impurity Hubbard model to the study of the spectrum of a simpler operator. We proved the essential spectra of the three-electron systems in the Impurity Hubbard model in the quartet state is the union of no more than six segments, and the discrete spectrum of the system is consists of no more than four eigenvalues.
