The Standard Model of particle physics involves twelve fundamental fermions, treated as point particles, in four charge states. However, the Standard Model does not explain why only three fermions are in each charge s...The Standard Model of particle physics involves twelve fundamental fermions, treated as point particles, in four charge states. However, the Standard Model does not explain why only three fermions are in each charge state or account for neutrino mass. This holographic analysis treats charged Standard Model fermions as spheres with mass 0.187 g/cm<sup>2</sup> times their surface area, using the proportionality constant in the holographic relation between mass of the observable universe and event horizon radius. The analysis requires three Standard Model fermions per charge state and relates up quark and down quark masses to electron mass. Holographic analysis specifies electron mass, to six significant figures, in terms of fundamental constants α,ℏ,G,Λ and Ω Λ . Treating neutrinos as spheres and equating electron neutrino energy density with cosmic vacuum energy density predicts neutrino masses consistent with experiment.展开更多
We constrain two dynamical dark energy models that are parametrized by the logarithm form of and the oscillating form of . Comparing with the Chevallier-Polarski-Linder (CPL) model, the two parametrizations for dark e...We constrain two dynamical dark energy models that are parametrized by the logarithm form of and the oscillating form of . Comparing with the Chevallier-Polarski-Linder (CPL) model, the two parametrizations for dark energy can explore the whole evolution history of the universe properly. Using the current mainstream observational data including the cosmic microwave background data and the baryon acoustic oscillation data as well as the type Ia supernovae data, we perform the X<sup>2</sup> statistic analysis to global fit these models, finding that the logarithm parametrization and the oscillating parameterization are almost as well as the CPL scenario in fitting these data. We make a comparison for the impacts of the dynamical dark energy on the cosmological constraints on the total mass of active neutrinos. We find that the logarithm parametrization and the oscillating parameterization can increase the fitting values of Σm<sub>v</sub>. Looser constraints on Σm<sub>v</sub> are obtained in the logarithm and oscillating models than those derived in the CPL model. Consideration of the possible mass ordering of neutrinos reveals that the most stringent constraint on Σm<sub>v</sub> appears in the degenerate hierarchy case.展开更多
In this paper, the submicroscopic deterministic concept developed by the author is applied to the problem of the neutrino mass. A particle appears from space considered as a mathematical lattice of primary topological...In this paper, the submicroscopic deterministic concept developed by the author is applied to the problem of the neutrino mass. A particle appears from space considered as a mathematical lattice of primary topological balls, and induces a deformation coat in its surrounding. The principles of the interaction of particles with space and through space between themselves are considered in detail. The approach states that real quarks possess only an integer charge (±e) and when moving they periodically change to the monopole state (⇄g) and hence, canonical particles are dynamic dyons. A neutrino emerges as a squeezed quark when it is in a monopole state, or in other words, the quark monopole state (a bubble in the tessellattice) is transferred to the appropriate lepton monopole state (a speck in the tessellattice). The self-mass (a “rest” mass) for each neutrino flavour is calculated. The calculated value of the self-mass for the electron anti-neutrino is 1.22873978 × 10<sup>-36</sup> kg = 0.68927247 eV/c<sup>2</sup>. The concept of neutrino oscillations is revised, and another postulation is proposed, namely, that the transition from lighter to heavier flavors is due to the inelastic scattering of neutrinos on oncoming scatterers. As a result, the neutrino captures the mass defect, becomes heavier, and therefore the transitions V<sub>e</sub>⟶V<sub>μ</sub> and V<sub>μ</sub>⟶V<sub>τ</sub> occur;thus, the number of light neutrinos decreases in the neutrino flux studied.展开更多
Recently,the emergence of cosmological tension has raised doubts about the consistency of the ACDM model.To constrain the neutrino mass within a consistent cosmological framework,we investigate three massive neutrinos...Recently,the emergence of cosmological tension has raised doubts about the consistency of the ACDM model.To constrain the neutrino mass within a consistent cosmological framework,we investigate three massive neutrinos with normal hierarchy(NH)and inverted hierarchy(IH)in both the axion-like early dark energy(AxiEDE)and AdS-EDE models.We use joint datasets including the cosmic microwave background power spectrum from Plaanck 2018,Pantheon of type la supernova,baryon acoustic oscillation,and H0data from SH0ES.For the vAxi-EDE model,we obtain∑m_(v),NH<0.152 eV and∑m_(v),IH<0.178 eV,whereas for the vAdS-EDE model,we find∑m_(v),NH<0.135 eV and∑m_(v),IH<0.167 eV.Our results exhibit a preference for NH in both the vAxi-EDE and vAdS-EDE models.展开更多
We constructed a gauge B-L model with D_(4)×Z_(4)×Z_(2)symmetry to explain the quark and lepton mass hierarchies and their mixings with realistic CP phases via the type-I seesaw mechanism.Six quark mases,thr...We constructed a gauge B-L model with D_(4)×Z_(4)×Z_(2)symmetry to explain the quark and lepton mass hierarchies and their mixings with realistic CP phases via the type-I seesaw mechanism.Six quark mases,three quark mixing angles,and the CP phase in the quark sector take the central values whereas Yukawa couplings in the quark sector are diluted in a range of difference of three orders of magnitude by the perturbation theory at the first order.Concerning the neutrino sector,a small neutrino mass is achieved by the type-I seesaw mechanism.Both inverted and normal neutrino mass hierarchies are consistent with the experimental data.The predicted sum of neutrino masses for normal and inverted hierarchies,the effective neutrino masses,and the Dirac CP phase are also consistent with recently reported limits.展开更多
In this study,we calculated the inclusive charged-current neutrino-nucleus scattering from ^(40)Ar in the quasielastic region.To explore the effect of uncertainties stemming from the nuclear structure,we used the KIDS...In this study,we calculated the inclusive charged-current neutrino-nucleus scattering from ^(40)Ar in the quasielastic region.To explore the effect of uncertainties stemming from the nuclear structure,we used the KIDS(Korea-IBS-Daegu-SKKU)nuclear energy density functional and Skyrme force models,namely SLy4,SkI3,and MSk7.These models were selected to have distinct behavior in terms of the density dependence of the symmetry energy and the effective mass of the nucleon.In the charged-current neutrino scattering,the single-and double-differential cross sections were calculated for various kinematics.Total cross sections are reported as a function of the incident neutrino energy.The theoretical cross sections were compared with experimental data,and the roles of the effective mass and symmetry energy were investigated in terms of charged-current neutrino-nucleus scattering.展开更多
We investigate the constraints on total neutrino mass in the scenario of vacuum energy interacting with cold dark matter. We focus on two typical interaction forms, i.e., Q=βHρc and Q=βHρΛ. To avoid the occurrenc...We investigate the constraints on total neutrino mass in the scenario of vacuum energy interacting with cold dark matter. We focus on two typical interaction forms, i.e., Q=βHρc and Q=βHρΛ. To avoid the occurrence of large-scale instability in interacting dark energy cosmology, we adopt the parameterized post-Friedmann approach to calculate the perturbation evolution of dark energy. We employ observational data, including the Planck cosmic microwave background temperature and polarization data, baryon acoustic oscillation data, a JLA sample of type Ia supernovae observation, direct measurement of the Hubble constant, and redshift space distortion data. We find that, compared with those in the ΛCDM model, much looser constraints onstraints are obtained in the Q=βHρΛ mode mν are obtained in the Q = βHρc model, whereas slightly tighter conl. Consideration of the possible mass hierarchies of neutrinos reveals that the smallest upper limit ofarchy mν appears in the degenerate hierarchy case. By comparing the values of χ~2 min, we find that the normal hiercase is favored over the inverted one. In particular,we find that the difference ？χ22 min ≡χIH;min-χ~2 NH;min〉 2 in the Q = βHρc model. In addition, we find that β = 0 is consistent with the current observations in the Q=βHρc model, and β 〈0 is favored at more than the 1σ level in the Q=βHρΛ model.展开更多
In the standard model of particle physics there are three species of neutrinos whose masses were originally assumed to be zero. But the discovery of solar and atmospheric neutrino oscillations indicates that neutrinos...In the standard model of particle physics there are three species of neutrinos whose masses were originally assumed to be zero. But the discovery of solar and atmospheric neutrino oscillations indicates that neutrinos are massive and lepton flavors are mixed. In this brief review we first give an overview of our current knowledge about the neutrino mass spectrum and lepton flavor mixing angles, and then comment on the seesaw mechanisms which allow us to understand the origin of tiny neutrino masses. We pay particular attention to the nearly tri-bi-maximal neutrino mixing pattern and the Friedberg-Lee symmetry to derive it. A relatively promising possibility of detecting hot and warm neutrino dark matter in the Universe will also be discussed.展开更多
Magic textures are successful candidates of the correct texture for Majorana neutrinos.In this study,we demonstrate that several types of magic textures of Majorana neutrinos are approximately immanent in the flavor m...Magic textures are successful candidates of the correct texture for Majorana neutrinos.In this study,we demonstrate that several types of magic textures of Majorana neutrinos are approximately immanent in the flavor mass matrix of Dirac neutrinos.In addition,the normal mass ordering of Dirac neutrino masses is slightly preferable to inverted mass ordering in the context of magic textures.展开更多
We investigate a cogenesis mechanism within the twin Higgs setup that can naturally explain the nature of dark matter,the cosmic coincidence puzzle,little hierarchy problem,leptogenesis,and the tiny neutrino masses.Th...We investigate a cogenesis mechanism within the twin Higgs setup that can naturally explain the nature of dark matter,the cosmic coincidence puzzle,little hierarchy problem,leptogenesis,and the tiny neutrino masses.Three heavy Majorana neutrinos are introduced to the standard model sector and the twin sector respectively,which explain the tiny neutrino masses and generate the lepton asymmetry and the twin lepton asymmetry at the same time.The twin cogenesis mechanism applies to any viable twin Higgs model without an explicit Z_(2)breaking in the leptonic sector and evading theΔN_(eff) constraint.We illustrate the twin cogenesis mechanism using the neutrino-philic twin two Higgs doublet model,a newly proposed model to lift the twin neutrino masses with spontaneous Z_(2)breaking.The dark photon with a Stueckelberg mass O(10)MeV ensures the energy in the twin sector as well as the symmetric component of twin sector particles can be depleted.The lightest twin baryons are the dark matter candidates with masses of approximately 5.5 GeV,which explains naturally the amount of dark matter and visible matter in the Universe are of the same order.We also demonstrate twin cogenesis in the fraternal twin Higgs setup,in which the dark matter candidate is the twin bottom bound stateΩ’_(b’b’b’).展开更多
We investigate how the dark energy properties impact the constraints on the total neutrino mass in interacting dark energy（IDE）models. In this study, we focus on two typical interacting dynamical dark energy models,...We investigate how the dark energy properties impact the constraints on the total neutrino mass in interacting dark energy（IDE）models. In this study, we focus on two typical interacting dynamical dark energy models, i.e., the interacting w cold dark matter（IwCDM） model and the interacting holographic dark energy（IHDE） model. To avoid the large-scale instability problem in IDE models, we apply the parameterized post-Friedmann approach to calculate the perturbation of dark energy. We employ the Planck 2015 cosmic microwave background temperature and polarization data, combined with low-redshift measurements on baryon acoustic oscillation distance scales, type Ia supernovae, and the Hubble constant, to constrain the cosmological parameters. We find that the dark energy properties could influence the constraint limits on the total neutrino mass. Once dynamical dark energy is considered in the IDE models, the upper bounds of ∑mν will be changed. By considering the values of χmin2 , we find that in these IDE models the normal hierarchy case is slightly preferred over the inverted hierarchy case; for example, ?χ2= 2.720 is given in the IHDE+∑mν model. In addition, we also find that in the Iw CDM+∑mν model β = 0 is consistent with current observational data inside the 1σ range, and in the IHDE+∑mν model β > 0 is favored at more than 2σ level.展开更多
We study an effective theory beyond the standard model(SM) where either of the two additional gauge singlets, a Majorana fermion and a real scalar, constitutes all or some fraction of dark matter. In particular, we fo...We study an effective theory beyond the standard model(SM) where either of the two additional gauge singlets, a Majorana fermion and a real scalar, constitutes all or some fraction of dark matter. In particular, we focus on the masses of the two singlets in the range of O(10) MeV-O(10) GeV with a neutrino portal interaction, which plays an important role not only in particle physics but also in cosmology and astronomy. We point out that the thermal dark matter abundance can be explained by(co-)annihilation, where the dark matter with a mass greater than 2 GeV can be tested in future lepton colliders, CEPC, ILC, FCC-ee and CLIC, in the light of the Higgs boson invisible decay. When the gauge singlets are lighter than O(100) MeV, the interaction can affect the neutrino propagation in the universe due to its annihilation with cosmic background neutrino into the gauge singlets. Although in this case it can not be the dominant dark matter, the singlets are produced by the invisible decay of the Higgs boson at such a rate which is fully within reach of future lepton colliders. In particular, a high energy cutoff of cosmic-ray neutrino,which may account for the non-detection of Greisen-Zatsepin-Kuzmin(GZK) neutrino or the non-observation of the Glashow resonance, can be set. Interestingly, given the cutoff and the mass(range) of WIMPs, a neutrino mass can be"measured" kinematically.展开更多
Study of neutrino properties is nowadays one of the most active domains of research in physics. On the one hand, fundamental properties of the neutrinos like their absolute mass, their character (are they Dirac or Maj...Study of neutrino properties is nowadays one of the most active domains of research in physics. On the one hand, fundamental properties of the neutrinos like their absolute mass, their character (are they Dirac or Majorana particles?) and the number of neutrino flavors, are still unknown. On the other hand, the knowledge of these properties are of great importance since the neutrinos are very abundant in nature and play a key role in nuclear and particle physics, astrophysics and cosmology. In addition, the results of the neutrino oscillation experiments have convincingly showed that neutrinos have mass and mix, in contradiction to the initial assumptions of the Standard Model. In this context there is an increased interest in the study of the Lepton Number Violating (LNV) processes, since they are capable to decide on the above mentioned neutrino properties. Since recently, the neutrinoless double beta (0nββ) decay was considered the only process able to distinguish between Dirac or Majorana neutrinos and to give a hint on the absolute mass of the electron neutrino. At present, the increased luminosity of the LHC experiments at CERN makes it feasable the search for LNV processes at LHC as well. Besides the neutrino character, these studies can also shed light on the existence of other types of neutrinos (the sterile neutrinos), than the three known ones. In this paper, I make a brief review on our present knowledge about the neutrino properties and on the way they can be probed by LNV processes at low- and high-energies. Particularly, I refer to the 0nββ decay process and to the first attempts of searching of LNV processes in hadron collider experiments, particularly in LHC experiments at CERN-Geneva.展开更多
文摘The Standard Model of particle physics involves twelve fundamental fermions, treated as point particles, in four charge states. However, the Standard Model does not explain why only three fermions are in each charge state or account for neutrino mass. This holographic analysis treats charged Standard Model fermions as spheres with mass 0.187 g/cm<sup>2</sup> times their surface area, using the proportionality constant in the holographic relation between mass of the observable universe and event horizon radius. The analysis requires three Standard Model fermions per charge state and relates up quark and down quark masses to electron mass. Holographic analysis specifies electron mass, to six significant figures, in terms of fundamental constants α,ℏ,G,Λ and Ω Λ . Treating neutrinos as spheres and equating electron neutrino energy density with cosmic vacuum energy density predicts neutrino masses consistent with experiment.
文摘We constrain two dynamical dark energy models that are parametrized by the logarithm form of and the oscillating form of . Comparing with the Chevallier-Polarski-Linder (CPL) model, the two parametrizations for dark energy can explore the whole evolution history of the universe properly. Using the current mainstream observational data including the cosmic microwave background data and the baryon acoustic oscillation data as well as the type Ia supernovae data, we perform the X<sup>2</sup> statistic analysis to global fit these models, finding that the logarithm parametrization and the oscillating parameterization are almost as well as the CPL scenario in fitting these data. We make a comparison for the impacts of the dynamical dark energy on the cosmological constraints on the total mass of active neutrinos. We find that the logarithm parametrization and the oscillating parameterization can increase the fitting values of Σm<sub>v</sub>. Looser constraints on Σm<sub>v</sub> are obtained in the logarithm and oscillating models than those derived in the CPL model. Consideration of the possible mass ordering of neutrinos reveals that the most stringent constraint on Σm<sub>v</sub> appears in the degenerate hierarchy case.
文摘In this paper, the submicroscopic deterministic concept developed by the author is applied to the problem of the neutrino mass. A particle appears from space considered as a mathematical lattice of primary topological balls, and induces a deformation coat in its surrounding. The principles of the interaction of particles with space and through space between themselves are considered in detail. The approach states that real quarks possess only an integer charge (±e) and when moving they periodically change to the monopole state (⇄g) and hence, canonical particles are dynamic dyons. A neutrino emerges as a squeezed quark when it is in a monopole state, or in other words, the quark monopole state (a bubble in the tessellattice) is transferred to the appropriate lepton monopole state (a speck in the tessellattice). The self-mass (a “rest” mass) for each neutrino flavour is calculated. The calculated value of the self-mass for the electron anti-neutrino is 1.22873978 × 10<sup>-36</sup> kg = 0.68927247 eV/c<sup>2</sup>. The concept of neutrino oscillations is revised, and another postulation is proposed, namely, that the transition from lighter to heavier flavors is due to the inelastic scattering of neutrinos on oncoming scatterers. As a result, the neutrino captures the mass defect, becomes heavier, and therefore the transitions V<sub>e</sub>⟶V<sub>μ</sub> and V<sub>μ</sub>⟶V<sub>τ</sub> occur;thus, the number of light neutrinos decreases in the neutrino flux studied.
基金XZ is supported by the National Natural Science Foundation of China(12005183)QGH is supported by the National Natural Science Foundation of China(12250010,11975019,11991052,12047503)the Key Research Program of Frontier Sciences,CAS,(ZDBS-LY7009)。
文摘Recently,the emergence of cosmological tension has raised doubts about the consistency of the ACDM model.To constrain the neutrino mass within a consistent cosmological framework,we investigate three massive neutrinos with normal hierarchy(NH)and inverted hierarchy(IH)in both the axion-like early dark energy(AxiEDE)and AdS-EDE models.We use joint datasets including the cosmic microwave background power spectrum from Plaanck 2018,Pantheon of type la supernova,baryon acoustic oscillation,and H0data from SH0ES.For the vAxi-EDE model,we obtain∑m_(v),NH<0.152 eV and∑m_(v),IH<0.178 eV,whereas for the vAdS-EDE model,we find∑m_(v),NH<0.135 eV and∑m_(v),IH<0.167 eV.Our results exhibit a preference for NH in both the vAxi-EDE and vAdS-EDE models.
基金funded by Tay Nguyen University under grant number T2023-45CBTD。
文摘We constructed a gauge B-L model with D_(4)×Z_(4)×Z_(2)symmetry to explain the quark and lepton mass hierarchies and their mixings with realistic CP phases via the type-I seesaw mechanism.Six quark mases,three quark mixing angles,and the CP phase in the quark sector take the central values whereas Yukawa couplings in the quark sector are diluted in a range of difference of three orders of magnitude by the perturbation theory at the first order.Concerning the neutrino sector,a small neutrino mass is achieved by the type-I seesaw mechanism.Both inverted and normal neutrino mass hierarchies are consistent with the experimental data.The predicted sum of neutrino masses for normal and inverted hierarchies,the effective neutrino masses,and the Dirac CP phase are also consistent with recently reported limits.
基金Supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(2018R1A5A1025563,2023R1A2C1003177,IBS-R031-D1)。
文摘In this study,we calculated the inclusive charged-current neutrino-nucleus scattering from ^(40)Ar in the quasielastic region.To explore the effect of uncertainties stemming from the nuclear structure,we used the KIDS(Korea-IBS-Daegu-SKKU)nuclear energy density functional and Skyrme force models,namely SLy4,SkI3,and MSk7.These models were selected to have distinct behavior in terms of the density dependence of the symmetry energy and the effective mass of the nucleon.In the charged-current neutrino scattering,the single-and double-differential cross sections were calculated for various kinematics.Total cross sections are reported as a function of the incident neutrino energy.The theoretical cross sections were compared with experimental data,and the roles of the effective mass and symmetry energy were investigated in terms of charged-current neutrino-nucleus scattering.
基金Supported by National Natural Science Foundation of China(11522540,11690021)the Top-Notch Young Talents Program of Chinathe Provincial Department of Education of Liaoning(L2012087)
文摘We investigate the constraints on total neutrino mass in the scenario of vacuum energy interacting with cold dark matter. We focus on two typical interaction forms, i.e., Q=βHρc and Q=βHρΛ. To avoid the occurrence of large-scale instability in interacting dark energy cosmology, we adopt the parameterized post-Friedmann approach to calculate the perturbation evolution of dark energy. We employ observational data, including the Planck cosmic microwave background temperature and polarization data, baryon acoustic oscillation data, a JLA sample of type Ia supernovae observation, direct measurement of the Hubble constant, and redshift space distortion data. We find that, compared with those in the ΛCDM model, much looser constraints onstraints are obtained in the Q=βHρΛ mode mν are obtained in the Q = βHρc model, whereas slightly tighter conl. Consideration of the possible mass hierarchies of neutrinos reveals that the smallest upper limit ofarchy mν appears in the degenerate hierarchy case. By comparing the values of χ~2 min, we find that the normal hiercase is favored over the inverted one. In particular,we find that the difference ？χ22 min ≡χIH;min-χ~2 NH;min〉 2 in the Q = βHρc model. In addition, we find that β = 0 is consistent with the current observations in the Q=βHρc model, and β 〈0 is favored at more than the 1σ level in the Q=βHρΛ model.
文摘In the standard model of particle physics there are three species of neutrinos whose masses were originally assumed to be zero. But the discovery of solar and atmospheric neutrino oscillations indicates that neutrinos are massive and lepton flavors are mixed. In this brief review we first give an overview of our current knowledge about the neutrino mass spectrum and lepton flavor mixing angles, and then comment on the seesaw mechanisms which allow us to understand the origin of tiny neutrino masses. We pay particular attention to the nearly tri-bi-maximal neutrino mixing pattern and the Friedberg-Lee symmetry to derive it. A relatively promising possibility of detecting hot and warm neutrino dark matter in the Universe will also be discussed.
文摘Magic textures are successful candidates of the correct texture for Majorana neutrinos.In this study,we demonstrate that several types of magic textures of Majorana neutrinos are approximately immanent in the flavor mass matrix of Dirac neutrinos.In addition,the normal mass ordering of Dirac neutrino masses is slightly preferable to inverted mass ordering in the context of magic textures.
基金supported in part by the National Natural Science Foundation of China under Grant No.11905158 and No.11935009Natural Science Foundation of Tianjin City under Grant No.20JCQNJC02030supported in part by the National Science Foundation of China under Grants No.11875003。
文摘We investigate a cogenesis mechanism within the twin Higgs setup that can naturally explain the nature of dark matter,the cosmic coincidence puzzle,little hierarchy problem,leptogenesis,and the tiny neutrino masses.Three heavy Majorana neutrinos are introduced to the standard model sector and the twin sector respectively,which explain the tiny neutrino masses and generate the lepton asymmetry and the twin lepton asymmetry at the same time.The twin cogenesis mechanism applies to any viable twin Higgs model without an explicit Z_(2)breaking in the leptonic sector and evading theΔN_(eff) constraint.We illustrate the twin cogenesis mechanism using the neutrino-philic twin two Higgs doublet model,a newly proposed model to lift the twin neutrino masses with spontaneous Z_(2)breaking.The dark photon with a Stueckelberg mass O(10)MeV ensures the energy in the twin sector as well as the symmetric component of twin sector particles can be depleted.The lightest twin baryons are the dark matter candidates with masses of approximately 5.5 GeV,which explains naturally the amount of dark matter and visible matter in the Universe are of the same order.We also demonstrate twin cogenesis in the fraternal twin Higgs setup,in which the dark matter candidate is the twin bottom bound stateΩ’_(b’b’b’).
基金supported by the National Natural Science Foundation of China(Grant Nos.11875102,11835009,11522540,11690021,and61603265)the National Program for Support of Top-Notch Young ProfessionalsDoctoral Research Project of Shenyang Normal University(Grant Nos.BS201844,and BS201702)
文摘We investigate how the dark energy properties impact the constraints on the total neutrino mass in interacting dark energy（IDE）models. In this study, we focus on two typical interacting dynamical dark energy models, i.e., the interacting w cold dark matter（IwCDM） model and the interacting holographic dark energy（IHDE） model. To avoid the large-scale instability problem in IDE models, we apply the parameterized post-Friedmann approach to calculate the perturbation of dark energy. We employ the Planck 2015 cosmic microwave background temperature and polarization data, combined with low-redshift measurements on baryon acoustic oscillation distance scales, type Ia supernovae, and the Hubble constant, to constrain the cosmological parameters. We find that the dark energy properties could influence the constraint limits on the total neutrino mass. Once dynamical dark energy is considered in the IDE models, the upper bounds of ∑mν will be changed. By considering the values of χmin2 , we find that in these IDE models the normal hierarchy case is slightly preferred over the inverted hierarchy case; for example, ?χ2= 2.720 is given in the IHDE+∑mν model. In addition, we also find that in the Iw CDM+∑mν model β = 0 is consistent with current observational data inside the 1σ range, and in the IHDE+∑mν model β > 0 is favored at more than 2σ level.
文摘We study an effective theory beyond the standard model(SM) where either of the two additional gauge singlets, a Majorana fermion and a real scalar, constitutes all or some fraction of dark matter. In particular, we focus on the masses of the two singlets in the range of O(10) MeV-O(10) GeV with a neutrino portal interaction, which plays an important role not only in particle physics but also in cosmology and astronomy. We point out that the thermal dark matter abundance can be explained by(co-)annihilation, where the dark matter with a mass greater than 2 GeV can be tested in future lepton colliders, CEPC, ILC, FCC-ee and CLIC, in the light of the Higgs boson invisible decay. When the gauge singlets are lighter than O(100) MeV, the interaction can affect the neutrino propagation in the universe due to its annihilation with cosmic background neutrino into the gauge singlets. Although in this case it can not be the dominant dark matter, the singlets are produced by the invisible decay of the Higgs boson at such a rate which is fully within reach of future lepton colliders. In particular, a high energy cutoff of cosmic-ray neutrino,which may account for the non-detection of Greisen-Zatsepin-Kuzmin(GZK) neutrino or the non-observation of the Glashow resonance, can be set. Interestingly, given the cutoff and the mass(range) of WIMPs, a neutrino mass can be"measured" kinematically.
文摘Study of neutrino properties is nowadays one of the most active domains of research in physics. On the one hand, fundamental properties of the neutrinos like their absolute mass, their character (are they Dirac or Majorana particles?) and the number of neutrino flavors, are still unknown. On the other hand, the knowledge of these properties are of great importance since the neutrinos are very abundant in nature and play a key role in nuclear and particle physics, astrophysics and cosmology. In addition, the results of the neutrino oscillation experiments have convincingly showed that neutrinos have mass and mix, in contradiction to the initial assumptions of the Standard Model. In this context there is an increased interest in the study of the Lepton Number Violating (LNV) processes, since they are capable to decide on the above mentioned neutrino properties. Since recently, the neutrinoless double beta (0nββ) decay was considered the only process able to distinguish between Dirac or Majorana neutrinos and to give a hint on the absolute mass of the electron neutrino. At present, the increased luminosity of the LHC experiments at CERN makes it feasable the search for LNV processes at LHC as well. Besides the neutrino character, these studies can also shed light on the existence of other types of neutrinos (the sterile neutrinos), than the three known ones. In this paper, I make a brief review on our present knowledge about the neutrino properties and on the way they can be probed by LNV processes at low- and high-energies. Particularly, I refer to the 0nββ decay process and to the first attempts of searching of LNV processes in hadron collider experiments, particularly in LHC experiments at CERN-Geneva.
