The spin-charge-family theory is a kind of the Kaluza-Klein theories, but with two kinds of the spin connection fields, which are the gauge fields of the two kinds of spins. The SO(13,1) representation of one kind of ...The spin-charge-family theory is a kind of the Kaluza-Klein theories, but with two kinds of the spin connection fields, which are the gauge fields of the two kinds of spins. The SO(13,1) representation of one kind of spins manifests in d = (3 + 1) all the properties of family members as assumed by the standard model;the second kind of spins explains the appearance of families. The gauge fields of the first kind, carrying the space index m = (0,...,3), manifest in d = (3 + 1) all the vector gauge fields assumed by the standard model. The gauge fields of both kinds of spins, which carry the space index (7, 8) gaining at the electroweak break nonzero vacuum expectation values, manifest in d = (3 + 1) as scalar fields with the properties of the Higgs scalar of the standard model with respect to the weak and the hyper charge ( and , respectively), while they carry additional quantum numbers in adjoint representations, offering correspondingly the explanation for the scalar Higgs and the Yukawa couplings, predicting the fourth family and the existence of several scalar fields. The paper 1) explains why in this theory the gauge fields are with the scalar index s = (5,6,7,8) doublets with respect to the weak and the hyper charge, while they are with respect to all the other charges in the adjoint representations;2) demonstrates that the spin connection fields manifest as the Kaluza-Klein vector gauge fields, which arise from the vielbeins;and 3) explains the role of the vielbeins and of both kinds of the spin connection fields.展开更多
The (extremely efficient) standard model of the elementary particles and fields makes several assumptions, which call for explanations. Any theory offering next step beyond the standard model must explain at least the...The (extremely efficient) standard model of the elementary particles and fields makes several assumptions, which call for explanations. Any theory offering next step beyond the standard model must explain at least the existence and properties of families and their members and correspondingly the existence of the scalar Higgs and the Yukawa couplings, which in this model take care of masses of fermions and weak bosons and influence the decaying properties of families. The spin-charge-family theory [1-11] is offering a possible explanation for the assumptions of the standard model—for the appearance of families and their members (for the charges of a family members), for the gauge fields, for the scalar fields—interpreting the standard model as its low energy effective manifestation. The spin-charge-family theory predicts at the low energy regime two decoupled groups of four families of quarks and leptons. The predicted fourth family waits to be observed, while the stable fifth family is the candidate to form the dark matter. In this paper properties of families are analysed. The appearance of several scalar fields, all in the bosonic (adjoint) representations with respect to the family groups, while they are doublets with respect to the weak charge, is presented, their properties discussed, it is explained how these scalar fields can effectively be interpreted as the standard model Higgs and the Yukawa couplings. The spin-charge-family theory predicts that there are no supersymmetric partners of the observed fermions and bosons.展开更多
We study the new Z' boson as a portal for the production of Higgs bosons h_(0) and H_(0) predicted by the Bestest Little Higgs Model through Higgs-strahlung processes μ^(+)μ^(-)→(Z,Z')→Zh_(0),ZH_(0).We foc...We study the new Z' boson as a portal for the production of Higgs bosons h_(0) and H_(0) predicted by the Bestest Little Higgs Model through Higgs-strahlung processes μ^(+)μ^(-)→(Z,Z')→Zh_(0),ZH_(0).We focus on the resonant and nonresonant effects of the Zh0,ZH0signals.In our analysis,we consider the center-of-mass energies of √s=3,4,6,10,30 TeV and integrated luminosities of L=2,4,6,10,30 ab^(-1) projected for a future muon collider.The possibility of performing precision measurements for Higgs bosons h_(0) and H_(0) is very promising for the future muon collider.Furthermore,our results may be useful to the High Energy Physics community.Complementarily,we generate and provide the Feynman rules necessary for studying processes μ+μ-→(Z,Z')→Zh_(0),ZH_(0).展开更多
The associated production of Z boson and a pair of new quarks at the Large Hadron Collider （LHC） is studied. The cross sections for both sequential fermions and vector-like fermions are presented. It is found that f...The associated production of Z boson and a pair of new quarks at the Large Hadron Collider （LHC） is studied. The cross sections for both sequential fermions and vector-like fermions are presented. It is found that for sequential fermions the cross sections can reach 1 - 10^2 /b for heavy quark mass mQ from 1000 GeV to 200 GeV. For vector-like quarks, the cross sections are suppressed by mixing parameter sin OL. Focusing on process pp → b＇b＇, we investigate the possibility of detecting the 6l 4- 2j signal. For a b＇ with light mass and a large branching ratio of b＇ → bZ, it is found that only several signal events （ parton level ） can be produced with 1000 fb^-1 integrated luminosity. Although the signal events are rare, all the final states are produced centrally and multi lepton final states are clear at hadron collider, which could be easily detected.展开更多
Motivated by the recently updated experimental measurement on Bd→μ^＋μ^- and B^-→π^-μ＋μ^- decays by CDF and Belle collaborations, we revisit these decays, as well as B^-→ρ^-μ^＋μ^- decay, within the Standa...Motivated by the recently updated experimental measurement on Bd→μ^＋μ^- and B^-→π^-μ＋μ^- decays by CDF and Belle collaborations, we revisit these decays, as well as B^-→ρ^-μ^＋μ^- decay, within the Standard Model, and evaluate the effects of a family non-universal Z＇ boson. Under the constraint from β（B- → π^-μ＋μ^-）, we find the ranges of the Z＇ couplings SLRμμ 〈 -5.2 × 10^-2 or Dμμ^LR 〈 -8.1 × 10^-2 are excluded. Within the allowed Z＇ parameters spaces, comparing with the SM predictions, we find that B（Bd→μ^＋μ^-）, B（B^-→π^-μ＋μ^-）, and B（B^-→ρ^-μ＋μ^-） could be enhanced by a factor about 226%, 245%, and 254%, respectively, by Z＇ contributions. However, they are hardly to be reduced. Furthermore, the zero crossing in the normalized forward-backward asymmetry spectrum of B^-→ρ^-μ＋μ^- decay at low dimuon mass always exists.展开更多
Motivated by the recent result reported from LHC on the di-photon search from the Standard Model (SM) Higgs boson, we obtain limits on the anomalous couplings Hγγ and HZγ. We also perform a calculation at tree leve...Motivated by the recent result reported from LHC on the di-photon search from the Standard Model (SM) Higgs boson, we obtain limits on the anomalous couplings Hγγ and HZγ. We also perform a calculation at tree level of the decay widths as well as of the branching ratios for the reactions H → γγ and H → Zγ in the context of effective lagrangian for Higgs boson masses 115 ≤MH ≤ 130 GeV. We find that the decay widths and branching ratios from these reactions enhanced significantly due to the anomalous Hγγ and HZγ vertex, which would lead to measurable effects in Higgs signals at the LHC. Moreover, our results complement other studies on the channels H → γγ and H → Zγ.展开更多
We report that a general principle of physical independence of mathematical background manifolds brings a replacement of common derivative operators by co-derivative ones. Then we obtain a new Lagrangian for the ordin...We report that a general principle of physical independence of mathematical background manifolds brings a replacement of common derivative operators by co-derivative ones. Then we obtain a new Lagrangian for the ordinary minimal standard model with supplementary terms containing the Lorentz invariance violation information measured by a new matrix, denoted as the Lorentz invariance violation matrix. We thus provide a new fundamental theory to study Lorentz invariance violation effects consistently and systematically.展开更多
We propose a low-scale Standard Model extension with T_(7)×Z_(4)×Z_(3)×Z_(2) symmetry that can successfully explain observed neutrino oscillation results within the 3σrange.Small neutrino masses are ob...We propose a low-scale Standard Model extension with T_(7)×Z_(4)×Z_(3)×Z_(2) symmetry that can successfully explain observed neutrino oscillation results within the 3σrange.Small neutrino masses are obtained via the linear seesaw mechanism.Normal and inverted neutrino mass orderings are considered with three lepton mixing angles in their experimentally allowed 3σranges.The model provides a suitable correlation between the solar and reactor neutrino mixing angles,which is consistent with the TM2 pattern.The prediction for the Dirac phase isδCP∈(295.80,330.0)°for both normal and inverted orderings,including its experimentally maximum value,while those for the two Majorana phases areη1∈(349.60,356.60)°,η2=0 for normal ordering andη1∈(3.44,10.37)°,η2=0 for inverted ordering.In addition,the predictions for the effective neutrino masses are consistent with the pre sent experimental bounds.展开更多
We propose a two-component dark matter explanation to the EDGES 21 cm anomalous signal.The heavier dark matter component is long-lived,and its decay is primarily responsible for the relic abundance of the lighter dark...We propose a two-component dark matter explanation to the EDGES 21 cm anomalous signal.The heavier dark matter component is long-lived,and its decay is primarily responsible for the relic abundance of the lighter dark matter,which is millicharged.To evade the constraints from CMB,underground dark matter direct detection,and XQC experiments,the lifetime of the heavier dark matter has to be larger than 0.1τU,whereτU is the age of the universe.Our model provides a viable realization of the millicharged dark matter model to explain the EDGES 21 cm signal,since the minimal model in which the relic density is generated via thermal freeze-out has been ruled out by various constraints.展开更多
Because both W-mass and muon g-2 can be affected by mass splittings among extra Higgs bosons(H,A,H^(±))in a two-Higgs-doublet model,we take a model with μ-τ lepton flavor violation interactions to examine the t...Because both W-mass and muon g-2 can be affected by mass splittings among extra Higgs bosons(H,A,H^(±))in a two-Higgs-doublet model,we take a model with μ-τ lepton flavor violation interactions to examine the two anomalies reported by CDFⅡ and FNAL.We obtain the following observations:(ⅰ)Combined with theoretical constraints,the CDF W-mass measurement disfavors H or A degenerating in mass with H^(±)but allows H and A to degenerate.The mass splitting between H^(±)and H/A must be larger than 10 GeV.m_(H) and m_(A) are favored to be smaller than 650 GeV for m_(H)<120 GeV and allowed to have larger values with increasing m_(H).(ⅱ)After imposing other relevant experimental constraints,there are parameter spaces that simultaneously satisfy(at the 2σ level)the CDF W-mass,FNAL muon g-2,and data on lepton universality in τ decays;however,the mass splittings among extra Higgs bosons are strictly constrained.展开更多
We present the angular distribution of the four-fold B→ρ(→ππ)µ^(+)µ^(−) and B→a_(1)(→ρ_(Ⅱ).⊥π)µ^(+)µ^(−) decays in the Standard Model and family non-universal Z'model.At the quark le...We present the angular distribution of the four-fold B→ρ(→ππ)µ^(+)µ^(−) and B→a_(1)(→ρ_(Ⅱ).⊥π)µ^(+)µ^(−) decays in the Standard Model and family non-universal Z'model.At the quark level,these decays are govered by the b→dµ^(+)µ^(−) transition.Along with different angular observables,we provide predictions of differential branching ra.tios,forward-backward asymmetry,and longitudinal polarization fractions of ρ and a_(1) mesons.Our analysis showsthat the signatures of the fimily non-universal Z’model are more distinct in the observables associated with the B→ρ(→ππ)µ^(+)µ^(−) decay than in those associated with the B→a_(1)(→ρ_(Ⅱ).⊥π)µ^(+)µ^(−) decay.Future measurements ofthe predicted angular observables,both at current and fiuture high energy colliders,will provide useful complement.ary data required to clarify the structure of the family non-universal Z' model in |△b|=△d|=1 processes.展开更多
In this study,we implemented the type Ⅱ seesaw mechanism into the framework of the U(l)B-L gauge model.To achieve this,we added a scalar triplet,A,to the canonical particle content of the U(l)B-Lgauge model.By imposi...In this study,we implemented the type Ⅱ seesaw mechanism into the framework of the U(l)B-L gauge model.To achieve this,we added a scalar triplet,A,to the canonical particle content of the U(l)B-Lgauge model.By imposing that the U(l)B-L gauge symmetry be spontaneously broken at TeV scale,we show that the type Ⅱ seesaw mechanism is realized at an intermediate energy scale,more precisely,at approximately 109 GeV.To prevent heavy right-handed neutrinos from disturbing the mechanism,we evoke a Z2 discrete symmetry.Interestingly,as a result,we have standard neutrinos with mass around eV scale and right-handed neutrinos with mass in TeV scale,with the lightest one fulfilling the condition of dark matter.We developed all of these in this study.In addition,we show that the neutral component of Δ may perform unproblematic non-minimal inflation with loss of unitarity.展开更多
With the discovery of a Higgs boson with a mass of 125 gigaelectronvolts(GeV)at the Large Hadron Collider(LHC)at CERN in 2012,the Standard Model(SM)is complete,and despite intensive searches,no new fundamental particl...With the discovery of a Higgs boson with a mass of 125 gigaelectronvolts(GeV)at the Large Hadron Collider(LHC)at CERN in 2012,the Standard Model(SM)is complete,and despite intensive searches,no new fundamental particle has been observed since then.In fact,a discovery can be challenging without a predictive new physics model because different channels and observables cannot be combined directly and unambiguously.Furthermore,without supporting indirect hints,the signal space to be searched is huge,resulting in diluted significances owing to the look-elsewhere effect.Several LHC processes with multiple leptons in the final state point towards the existence of a new Higgs boson with a mass between 140 GeV to 160 GeV decaying mostly to W bosons.While the former strongly reduces the look-elsewhere effect,the latter indicates that it could be a Higgs triplet with zero hypercharge.Within this simple and predictive extension of the SM,we simulate and combine different channels of diphoton production in association with leptons,missing energy,jets,etc...Using the full run-2 results by ATLAS,including those presented recently at the Moriond conference,an increased significance of 4 standard deviations is obtained for a≈152 GeV Higgs.Due to the previously predicted mass range,the look-elsewhere effect is negligible,and this constitutes the highest statistical evidence for a new narrow resonance obtained at the LHC.Furthermore,the model predicts a heavier-than-expected W boson,as indicated by the global electroweak fit.If further substantiated,the discovery of a new Higgs would overthrow the SM,provide a compelling case for the construction of future particle colliders,and pave the way to a novel understanding of the known shortcomings of the SM.In particular,the triplet Higgs field can lead to a strong first-order phase transition and could thus be related to the matter antimatter asymmetry in our Universe.展开更多
We study the CP-violating(CPV)neutral triple gauge couplings(nTGCs)that can be realized via dimension-8 operators in the Standard Model Effective Field Theory(SMEFT).We present a new formulation of the CPV nTGC form f...We study the CP-violating(CPV)neutral triple gauge couplings(nTGCs)that can be realized via dimension-8 operators in the Standard Model Effective Field Theory(SMEFT).We present a new formulation of the CPV nTGC form factors that is compat-ible with the spontaneous breaking of the electroweak gauge symmetry,and show how these CPV form factors can be matched consistently with the corresponding dimension-8 CPV nTGC operators in the broken phase.We then study probes of the CPV nTGCs at future high-energy e^(+)e^(−)colliders with centre-of-mass energies√s=0.25,0.5,1,3,5 TeV,respectively,demonstrating that the e■beam polarizations can help to improve the sensitivities of probes of the nTGCs.We estimate that the sensitivity reaches for probing the new physics scales of nTGCs can range from O(TeV)at a 250 GeV e^(+)e^(−)collider to O(10 TeV)at an e^(+)e^(−)collider of energy 3-5 TeV,and that the sensitivities to the nTGC form factors vary from O(10^(−4))to O(10^(−6)-10^(−8))for the e^(+)e^(−)collision energy from 250 GeV to 3-5 TeV.展开更多
Neutral triple gauge couplings(nTGCs)are absent in the standard model effective theory up to dimension-6 operators,but could arise from dimension-8 effective operators.In this work,we study the pure gauge operators of...Neutral triple gauge couplings(nTGCs)are absent in the standard model effective theory up to dimension-6 operators,but could arise from dimension-8 effective operators.In this work,we study the pure gauge operators of dimension-8 that contribute to nTGCs and are independent of the dimension-8 operator involving the Higgs doublet.We show that the pure gauge operators generate both ZγZ^*and Zγγ^*vertices with rapid energy dependence∝E^5,which can be probed sensitively via the reaction e^+e^-→Zγ.We demonstrate that measuring the nTGCs via the reaction e^+e^-→Zγfollowed by Z→qq decays can probe the new physics scales of dimension-8 pure gauge operators up to the range(1-5)TeV at the CEPC,FCC-ee and ILC colliders with s~(1/2)=(0.25-1)TeV,and up to the range(10-16)TeV at CLIC with s~(1/2)=(3-5)TeV,assuming in each case an integrated luminosity of 5 ab~(-1).We compare these sensitivities with the corresponding probes of the dimension-8 nTGC operators involving Higgs doublets and the dimension-8 fermionic contact operators that contribute to the e^+e^-Zγvertex.展开更多
We investigate the resonant production of color octet muons in order to explore the discovery potential of Future Circular Collider（FCC）-based μp colliders.It is shown that the search potentials of μp colliders es...We investigate the resonant production of color octet muons in order to explore the discovery potential of Future Circular Collider（FCC）-based μp colliders.It is shown that the search potentials of μp colliders essentially surpass the potential of the LHC and would exceed that of the FCC pp collider.展开更多
By comparing the cross Sections for left-and right-handed electrons scattered from various unpolarized nuclear targets,the small parity-violating asymmetry can be measured.These asymmetry data probe a wide variety of ...By comparing the cross Sections for left-and right-handed electrons scattered from various unpolarized nuclear targets,the small parity-violating asymmetry can be measured.These asymmetry data probe a wide variety of important topies,including searches for new fundamental interactions and important features of nuclear structure that cannot be studied with other probes.A special feature of these experiments is that the results are interpreted with remarkably few theoretical uncertainties,which justifies pushing the experiments to the highest possible precision.To measure the small asymmetries accurately,a number of novel experimental techniques have been developed.展开更多
We study stochastic gravitational waves from cosmic strings generated in an ultraviolet-complete model for pseudo-Nambu-Goldstone dark matter with a hidden U(1)gauge symmetry.The dark matter candidate in this model ca...We study stochastic gravitational waves from cosmic strings generated in an ultraviolet-complete model for pseudo-Nambu-Goldstone dark matter with a hidden U(1)gauge symmetry.The dark matter candidate in this model can naturally evade direct detection bounds and easily satisfy other phenomenological constraints.The bound on the dark matter lifetime implies an ultraviolet scale higher than 10^(9)GeV.The spontaneous U(1)symmetry breaking at such a high scale would induce cosmic strings with high tension,resulting in a stochastic gravitational wave background with a high energy density.We investigate the constraints from current gravitational wave experiments as well as the future sensitivity.We find that most viable parameter points can be well studied in future gravitational waveexperiments.展开更多
We study the possibility of probing high scale phase transitions that are inaccessible by LIGO.Our study shows that the stochastic gravitational-wave radiation from cosmic strings that are formed after the first-order...We study the possibility of probing high scale phase transitions that are inaccessible by LIGO.Our study shows that the stochastic gravitational-wave radiation from cosmic strings that are formed after the first-order phase transition can be detected by space-based interferometers when the phase transition temperature is T_(n)~O(10^(8−11))GeV.展开更多
We study a double covering of modular A_(4)flavor symmetry.To this end,we construct lepton models for canonical and radiative seesaw scenarios.Using irreducible doublet representations,heavier Majorana fermion masses ...We study a double covering of modular A_(4)flavor symmetry.To this end,we construct lepton models for canonical and radiative seesaw scenarios.Using irreducible doublet representations,heavier Majorana fermion masses are characterized by one free parameter that would differentiate from A_(4)symmetry.symmetry.Throughχsquare numerical analysis,we demonstrate that both scenarios produce some predictions in case of normal hierarchy reproducing neutrino oscillation data.However,no solution satisfies the neutrino oscillation data in case of radiative seesaw of inverted hierarchy.展开更多
文摘The spin-charge-family theory is a kind of the Kaluza-Klein theories, but with two kinds of the spin connection fields, which are the gauge fields of the two kinds of spins. The SO(13,1) representation of one kind of spins manifests in d = (3 + 1) all the properties of family members as assumed by the standard model;the second kind of spins explains the appearance of families. The gauge fields of the first kind, carrying the space index m = (0,...,3), manifest in d = (3 + 1) all the vector gauge fields assumed by the standard model. The gauge fields of both kinds of spins, which carry the space index (7, 8) gaining at the electroweak break nonzero vacuum expectation values, manifest in d = (3 + 1) as scalar fields with the properties of the Higgs scalar of the standard model with respect to the weak and the hyper charge ( and , respectively), while they carry additional quantum numbers in adjoint representations, offering correspondingly the explanation for the scalar Higgs and the Yukawa couplings, predicting the fourth family and the existence of several scalar fields. The paper 1) explains why in this theory the gauge fields are with the scalar index s = (5,6,7,8) doublets with respect to the weak and the hyper charge, while they are with respect to all the other charges in the adjoint representations;2) demonstrates that the spin connection fields manifest as the Kaluza-Klein vector gauge fields, which arise from the vielbeins;and 3) explains the role of the vielbeins and of both kinds of the spin connection fields.
文摘The (extremely efficient) standard model of the elementary particles and fields makes several assumptions, which call for explanations. Any theory offering next step beyond the standard model must explain at least the existence and properties of families and their members and correspondingly the existence of the scalar Higgs and the Yukawa couplings, which in this model take care of masses of fermions and weak bosons and influence the decaying properties of families. The spin-charge-family theory [1-11] is offering a possible explanation for the assumptions of the standard model—for the appearance of families and their members (for the charges of a family members), for the gauge fields, for the scalar fields—interpreting the standard model as its low energy effective manifestation. The spin-charge-family theory predicts at the low energy regime two decoupled groups of four families of quarks and leptons. The predicted fourth family waits to be observed, while the stable fifth family is the candidate to form the dark matter. In this paper properties of families are analysed. The appearance of several scalar fields, all in the bosonic (adjoint) representations with respect to the family groups, while they are doublets with respect to the weak charge, is presented, their properties discussed, it is explained how these scalar fields can effectively be interpreted as the standard model Higgs and the Yukawa couplings. The spin-charge-family theory predicts that there are no supersymmetric partners of the observed fermions and bosons.
文摘We study the new Z' boson as a portal for the production of Higgs bosons h_(0) and H_(0) predicted by the Bestest Little Higgs Model through Higgs-strahlung processes μ^(+)μ^(-)→(Z,Z')→Zh_(0),ZH_(0).We focus on the resonant and nonresonant effects of the Zh0,ZH0signals.In our analysis,we consider the center-of-mass energies of √s=3,4,6,10,30 TeV and integrated luminosities of L=2,4,6,10,30 ab^(-1) projected for a future muon collider.The possibility of performing precision measurements for Higgs bosons h_(0) and H_(0) is very promising for the future muon collider.Furthermore,our results may be useful to the High Energy Physics community.Complementarily,we generate and provide the Feynman rules necessary for studying processes μ+μ-→(Z,Z')→Zh_(0),ZH_(0).
基金Supported in part by the National Science Foundation of China under Grant Nos.90503002 and 10821504by the National Basic Research Program of China under Grant No.2010CB833000
文摘The associated production of Z boson and a pair of new quarks at the Large Hadron Collider （LHC） is studied. The cross sections for both sequential fermions and vector-like fermions are presented. It is found that for sequential fermions the cross sections can reach 1 - 10^2 /b for heavy quark mass mQ from 1000 GeV to 200 GeV. For vector-like quarks, the cross sections are suppressed by mixing parameter sin OL. Focusing on process pp → b＇b＇, we investigate the possibility of detecting the 6l 4- 2j signal. For a b＇ with light mass and a large branching ratio of b＇ → bZ, it is found that only several signal events （ parton level ） can be produced with 1000 fb^-1 integrated luminosity. Although the signal events are rare, all the final states are produced centrally and multi lepton final states are clear at hadron collider, which could be easily detected.
基金Supported by the National Natural Science Foundation under Grant Nos. 11105043 and 11075059Research Fund for the Doctoral Program of Higher Education of China under Grant No. 20114104120002Startup Foundation for Doctor of Henan Normal University under Grant No. 1006
文摘Motivated by the recently updated experimental measurement on Bd→μ^＋μ^- and B^-→π^-μ＋μ^- decays by CDF and Belle collaborations, we revisit these decays, as well as B^-→ρ^-μ^＋μ^- decay, within the Standard Model, and evaluate the effects of a family non-universal Z＇ boson. Under the constraint from β（B- → π^-μ＋μ^-）, we find the ranges of the Z＇ couplings SLRμμ 〈 -5.2 × 10^-2 or Dμμ^LR 〈 -8.1 × 10^-2 are excluded. Within the allowed Z＇ parameters spaces, comparing with the SM predictions, we find that B（Bd→μ^＋μ^-）, B（B^-→π^-μ＋μ^-）, and B（B^-→ρ^-μ＋μ^-） could be enhanced by a factor about 226%, 245%, and 254%, respectively, by Z＇ contributions. However, they are hardly to be reduced. Furthermore, the zero crossing in the normalized forward-backward asymmetry spectrum of B^-→ρ^-μ＋μ^- decay at low dimuon mass always exists.
文摘Motivated by the recent result reported from LHC on the di-photon search from the Standard Model (SM) Higgs boson, we obtain limits on the anomalous couplings Hγγ and HZγ. We also perform a calculation at tree level of the decay widths as well as of the branching ratios for the reactions H → γγ and H → Zγ in the context of effective lagrangian for Higgs boson masses 115 ≤MH ≤ 130 GeV. We find that the decay widths and branching ratios from these reactions enhanced significantly due to the anomalous Hγγ and HZγ vertex, which would lead to measurable effects in Higgs signals at the LHC. Moreover, our results complement other studies on the channels H → γγ and H → Zγ.
基金Supported by National Natural Science Foundation of China (11021092, 10975003, 11035003)Key Grant Project of Chinese Ministry of Education (305001)
文摘We report that a general principle of physical independence of mathematical background manifolds brings a replacement of common derivative operators by co-derivative ones. Then we obtain a new Lagrangian for the ordinary minimal standard model with supplementary terms containing the Lorentz invariance violation information measured by a new matrix, denoted as the Lorentz invariance violation matrix. We thus provide a new fundamental theory to study Lorentz invariance violation effects consistently and systematically.
文摘We propose a low-scale Standard Model extension with T_(7)×Z_(4)×Z_(3)×Z_(2) symmetry that can successfully explain observed neutrino oscillation results within the 3σrange.Small neutrino masses are obtained via the linear seesaw mechanism.Normal and inverted neutrino mass orderings are considered with three lepton mixing angles in their experimentally allowed 3σranges.The model provides a suitable correlation between the solar and reactor neutrino mixing angles,which is consistent with the TM2 pattern.The prediction for the Dirac phase isδCP∈(295.80,330.0)°for both normal and inverted orderings,including its experimentally maximum value,while those for the two Majorana phases areη1∈(349.60,356.60)°,η2=0 for normal ordering andη1∈(3.44,10.37)°,η2=0 for inverted ordering.In addition,the predictions for the effective neutrino masses are consistent with the pre sent experimental bounds.
基金Supported in part by the National Natural Science Foundation of China(11775109)。
文摘We propose a two-component dark matter explanation to the EDGES 21 cm anomalous signal.The heavier dark matter component is long-lived,and its decay is primarily responsible for the relic abundance of the lighter dark matter,which is millicharged.To evade the constraints from CMB,underground dark matter direct detection,and XQC experiments,the lifetime of the heavier dark matter has to be larger than 0.1τU,whereτU is the age of the universe.Our model provides a viable realization of the millicharged dark matter model to explain the EDGES 21 cm signal,since the minimal model in which the relic density is generated via thermal freeze-out has been ruled out by various constraints.
基金Supported by the National Natural Science Foundation of China(11975013,12105248,11821505,12075300,12075213)Peng-Huan-Wu Theoretical Physics Innovation Center(12047503)+1 种基金the Chinese Academy of Sciences Center for Excellence in Particle Physics(CCEPP)the Key Research Program of the Chinese Academy of Sciences(XDPB15)。
文摘Because both W-mass and muon g-2 can be affected by mass splittings among extra Higgs bosons(H,A,H^(±))in a two-Higgs-doublet model,we take a model with μ-τ lepton flavor violation interactions to examine the two anomalies reported by CDFⅡ and FNAL.We obtain the following observations:(ⅰ)Combined with theoretical constraints,the CDF W-mass measurement disfavors H or A degenerating in mass with H^(±)but allows H and A to degenerate.The mass splitting between H^(±)and H/A must be larger than 10 GeV.m_(H) and m_(A) are favored to be smaller than 650 GeV for m_(H)<120 GeV and allowed to have larger values with increasing m_(H).(ⅱ)After imposing other relevant experimental constraints,there are parameter spaces that simultaneously satisfy(at the 2σ level)the CDF W-mass,FNAL muon g-2,and data on lepton universality in τ decays;however,the mass splittings among extra Higgs bosons are strictly constrained.
基金Supported by the Higher Education Commission of Pakistan through(NRPU/20-15142)。
文摘We present the angular distribution of the four-fold B→ρ(→ππ)µ^(+)µ^(−) and B→a_(1)(→ρ_(Ⅱ).⊥π)µ^(+)µ^(−) decays in the Standard Model and family non-universal Z'model.At the quark level,these decays are govered by the b→dµ^(+)µ^(−) transition.Along with different angular observables,we provide predictions of differential branching ra.tios,forward-backward asymmetry,and longitudinal polarization fractions of ρ and a_(1) mesons.Our analysis showsthat the signatures of the fimily non-universal Z’model are more distinct in the observables associated with the B→ρ(→ππ)µ^(+)µ^(−) decay than in those associated with the B→a_(1)(→ρ_(Ⅱ).⊥π)µ^(+)µ^(−) decay.Future measurements ofthe predicted angular observables,both at current and fiuture high energy colliders,will provide useful complement.ary data required to clarify the structure of the family non-universal Z' model in |△b|=△d|=1 processes.
基金Supported by Conselho Nacional de Pesquisae Desenvolvimento Cintifico-CNPq(C.A.S.P)and Coordenacao de Aperfeicoamento de Pesscal de Nivel Superi-or-CAPES(A.C.O.S and J.G.R).
文摘In this study,we implemented the type Ⅱ seesaw mechanism into the framework of the U(l)B-L gauge model.To achieve this,we added a scalar triplet,A,to the canonical particle content of the U(l)B-Lgauge model.By imposing that the U(l)B-L gauge symmetry be spontaneously broken at TeV scale,we show that the type Ⅱ seesaw mechanism is realized at an intermediate energy scale,more precisely,at approximately 109 GeV.To prevent heavy right-handed neutrinos from disturbing the mechanism,we evoke a Z2 discrete symmetry.Interestingly,as a result,we have standard neutrinos with mass around eV scale and right-handed neutrinos with mass in TeV scale,with the lightest one fulfilling the condition of dark matter.We developed all of these in this study.In addition,we show that the neutral component of Δ may perform unproblematic non-minimal inflation with loss of unitarity.
基金supported by a Professorship Grant from the Swiss National Science Foundation(PP00P21_76884)partially supported by the National Natural Science Foundation of China(11835013)。
文摘With the discovery of a Higgs boson with a mass of 125 gigaelectronvolts(GeV)at the Large Hadron Collider(LHC)at CERN in 2012,the Standard Model(SM)is complete,and despite intensive searches,no new fundamental particle has been observed since then.In fact,a discovery can be challenging without a predictive new physics model because different channels and observables cannot be combined directly and unambiguously.Furthermore,without supporting indirect hints,the signal space to be searched is huge,resulting in diluted significances owing to the look-elsewhere effect.Several LHC processes with multiple leptons in the final state point towards the existence of a new Higgs boson with a mass between 140 GeV to 160 GeV decaying mostly to W bosons.While the former strongly reduces the look-elsewhere effect,the latter indicates that it could be a Higgs triplet with zero hypercharge.Within this simple and predictive extension of the SM,we simulate and combine different channels of diphoton production in association with leptons,missing energy,jets,etc...Using the full run-2 results by ATLAS,including those presented recently at the Moriond conference,an increased significance of 4 standard deviations is obtained for a≈152 GeV Higgs.Due to the previously predicted mass range,the look-elsewhere effect is negligible,and this constitutes the highest statistical evidence for a new narrow resonance obtained at the LHC.Furthermore,the model predicts a heavier-than-expected W boson,as indicated by the global electroweak fit.If further substantiated,the discovery of a new Higgs would overthrow the SM,provide a compelling case for the construction of future particle colliders,and pave the way to a novel understanding of the known shortcomings of the SM.In particular,the triplet Higgs field can lead to a strong first-order phase transition and could thus be related to the matter antimatter asymmetry in our Universe.
基金The work of John Ellis was supported in part by the United Kingdom STFC(Grant No.ST/T000759/1)The work of Hong-Jian He and Rui-Qing Xiao were supported in part by the National Natural Science Foundation of China(Grant Nos.12175136,and 12435005)+4 种基金the Shenzhen Science and Technology Program(Grant No.JCYJ20240813150911015)the State Key Laboratory of Dark Matter Physics,the Key Laboratory for Particle Astrophysics and Cosmology(MOE)the Shanghai Key Laboratory for Particle Physics and Cosmology.Rui-Qing Xiao is also supported in part by the National Science Foundation of China(Grant Nos.12175006,12188102,and 12061141002)the Ministry of Science and Technology of China(Grant No.2023YFA1605800)the State Key Laboratory of Nuclear Physics and Technology.
文摘We study the CP-violating(CPV)neutral triple gauge couplings(nTGCs)that can be realized via dimension-8 operators in the Standard Model Effective Field Theory(SMEFT).We present a new formulation of the CPV nTGC form factors that is compat-ible with the spontaneous breaking of the electroweak gauge symmetry,and show how these CPV form factors can be matched consistently with the corresponding dimension-8 CPV nTGC operators in the broken phase.We then study probes of the CPV nTGCs at future high-energy e^(+)e^(−)colliders with centre-of-mass energies√s=0.25,0.5,1,3,5 TeV,respectively,demonstrating that the e■beam polarizations can help to improve the sensitivities of probes of the nTGCs.We estimate that the sensitivity reaches for probing the new physics scales of nTGCs can range from O(TeV)at a 250 GeV e^(+)e^(−)collider to O(10 TeV)at an e^(+)e^(−)collider of energy 3-5 TeV,and that the sensitivities to the nTGC form factors vary from O(10^(−4))to O(10^(−6)-10^(−8))for the e^(+)e^(−)collision energy from 250 GeV to 3-5 TeV.
基金supported in part by United Kingdom STFC(Grant No.ST/P000258/1)in part by the Estonian Research Council via a Mobilitas Pluss grant+5 种基金in part by the TDLI distinguished visiting fellow programmesupported in part by the National Natural Science Foundation of China(Grant Nos.11675086,and 11835005)supported in part by the CAS Center for Excellence in Particle Physics(CCEPP)the National Key R&D Program of China(Grant No.2017YFA0402204)the Key Laboratory for Particle Physics,Astrophysics and Cosmology(Ministry of Education)the Office of Science and Technology,Shanghai Municipal Government(Grant No.16DZ2260200)。
文摘Neutral triple gauge couplings(nTGCs)are absent in the standard model effective theory up to dimension-6 operators,but could arise from dimension-8 effective operators.In this work,we study the pure gauge operators of dimension-8 that contribute to nTGCs and are independent of the dimension-8 operator involving the Higgs doublet.We show that the pure gauge operators generate both ZγZ^*and Zγγ^*vertices with rapid energy dependence∝E^5,which can be probed sensitively via the reaction e^+e^-→Zγ.We demonstrate that measuring the nTGCs via the reaction e^+e^-→Zγfollowed by Z→qq decays can probe the new physics scales of dimension-8 pure gauge operators up to the range(1-5)TeV at the CEPC,FCC-ee and ILC colliders with s~(1/2)=(0.25-1)TeV,and up to the range(10-16)TeV at CLIC with s~(1/2)=(3-5)TeV,assuming in each case an integrated luminosity of 5 ab~(-1).We compare these sensitivities with the corresponding probes of the dimension-8 nTGC operators involving Higgs doublets and the dimension-8 fermionic contact operators that contribute to the e^+e^-Zγvertex.
文摘We investigate the resonant production of color octet muons in order to explore the discovery potential of Future Circular Collider（FCC）-based μp colliders.It is shown that the search potentials of μp colliders essentially surpass the potential of the LHC and would exceed that of the FCC pp collider.
基金Department of Energy(DOE)under grants DE-FG02-84ER40146(PAS)DE-FG02-07ER41522(KDP).
文摘By comparing the cross Sections for left-and right-handed electrons scattered from various unpolarized nuclear targets,the small parity-violating asymmetry can be measured.These asymmetry data probe a wide variety of important topies,including searches for new fundamental interactions and important features of nuclear structure that cannot be studied with other probes.A special feature of these experiments is that the results are interpreted with remarkably few theoretical uncertainties,which justifies pushing the experiments to the highest possible precision.To measure the small asymmetries accurately,a number of novel experimental techniques have been developed.
基金Supported by the National Natural Science Foundation of China(11805288)。
文摘We study stochastic gravitational waves from cosmic strings generated in an ultraviolet-complete model for pseudo-Nambu-Goldstone dark matter with a hidden U(1)gauge symmetry.The dark matter candidate in this model can naturally evade direct detection bounds and easily satisfy other phenomenological constraints.The bound on the dark matter lifetime implies an ultraviolet scale higher than 10^(9)GeV.The spontaneous U(1)symmetry breaking at such a high scale would induce cosmic strings with high tension,resulting in a stochastic gravitational wave background with a high energy density.We investigate the constraints from current gravitational wave experiments as well as the future sensitivity.We find that most viable parameter points can be well studied in future gravitational waveexperiments.
基金supported in part by the National Key Research and Development Program of China(2021YFC2203004)in part by the National Natural Science Foundation of China(12075041,12047564)+1 种基金the Fundamental Research Funds for the Central Universities of China(2021CDJQY-011,2020CDJQY-Z003)Chongqing Natural Science Foundation(cstc2020jcyj-msxmX0814)。
文摘We study the possibility of probing high scale phase transitions that are inaccessible by LIGO.Our study shows that the stochastic gravitational-wave radiation from cosmic strings that are formed after the first-order phase transition can be detected by space-based interferometers when the phase transition temperature is T_(n)~O(10^(8−11))GeV.
基金supported by the Junior Research Group (JRG) Program at the Asia-Pacific Center for Theoretical Physics (APCTP) through the Science and Technology Promotion Fund and Lottery Fund of the Korean Governmentsupported by the Korean Local Governments-Gyeongsangbuk-do Province and Pohang Citysupported from European Regional Development Fund-Project Engineering Applications of Microworld Physics (No.CZ.02.1.01/0.0/0.0/16_019/0000766)
文摘We study a double covering of modular A_(4)flavor symmetry.To this end,we construct lepton models for canonical and radiative seesaw scenarios.Using irreducible doublet representations,heavier Majorana fermion masses are characterized by one free parameter that would differentiate from A_(4)symmetry.symmetry.Throughχsquare numerical analysis,we demonstrate that both scenarios produce some predictions in case of normal hierarchy reproducing neutrino oscillation data.However,no solution satisfies the neutrino oscillation data in case of radiative seesaw of inverted hierarchy.
