Sterile neutrinos can influence the evolution of the Universe,and thus cosmological observations can be used to detect them.Future gravitational-wave(GW)observations can precisely measure absolute cosmological distanc...Sterile neutrinos can influence the evolution of the Universe,and thus cosmological observations can be used to detect them.Future gravitational-wave(GW)observations can precisely measure absolute cosmological distances,helping to break parameter degeneracies generated by traditional cosmological observations.This advancement can lead to much tighter constraints on sterile neutrino parameters.This work provides a preliminary forecast for detecting sterile neutrinos using third-generation GW detectors in combination with future shortγ-ray burst observations from a THESEUS-like telescope,an approach not previously explored in the literature.Both massless and massive sterile neutrinos are considered within theΛCDM cosmology.We find that using GW data can greatly enhance the detection capability for massless sterile neutrinos,reaching 3σlevel.For massive sterile neutrinos,GW data can also greatly assist in improving the parameter constraints,but it seems that effective detection is still not feasible.展开更多
It is the current belief of the Physics Community that neutrinos are bereft of Charge because of Conservation of Charge in decay processes such as Beta Decay and are point particles with no physical size or shape. It ...It is the current belief of the Physics Community that neutrinos are bereft of Charge because of Conservation of Charge in decay processes such as Beta Decay and are point particles with no physical size or shape. It is the purpose of this paper to calculate the charges and the size of the electron neutrino, the muon neutrino, and the tau neutrino based on data available of their rest masses using the charges and rest masses of the electron, muon, and tau leptons from the Standard Model of Particle Physics Table. We base our calculations on the premise that Energy can create both Mass and Charge. Charge by itself is not conserved in any process that produces neutrinos. Only Total Energy is conserved.展开更多
Reliable observations find only three neutrino mass eigenstates, oscillating between each other as neutrinos travel through space, and limit the sum of the three neutrino masses. At a minimum, any reliable description...Reliable observations find only three neutrino mass eigenstates, oscillating between each other as neutrinos travel through space, and limit the sum of the three neutrino masses. At a minimum, any reliable description of neutrinos must allow only three neutrino mass eigenstates and predict a neutrino mass sum consistent with observations. This paper describes neutrinos as spheres, with radius one quarter of their Compton wavelength and thickness of the Planck length, surrounding a central core along their rotation axis, with diameter of the Planck length. This description of neutrinos as excitations of the vacuum energy allows only three neutrino mass eigenstates and predicts a neutrino mass sum consistent with observations.展开更多
In this manuscript we discuss mass-varying neutrinos and propose their energy density to exceed that of baryonic and dark matter. We introduce cosmic Large Grains whose mass is about Planck mass, and their temperature...In this manuscript we discuss mass-varying neutrinos and propose their energy density to exceed that of baryonic and dark matter. We introduce cosmic Large Grains whose mass is about Planck mass, and their temperature is around 29 K. Large Grains are in fact Bose-Einstein condensates of proposed dineutrinos, and are responsible for the cosmic Far-Infrared Background (FIRB) radiation. The distribution of the energy density of all components of the World (protons, electrons, photons, neutrinos, and dark matter particles) is considered. We present an overview of the World- Universe Model (WUM) and pay particular attention to the self-consistent set of time-varying values of basic parameters of the World: the age and critical energy density;Newtonian parameter of gravitation and Hubble’s parameter;temperatures of the cosmic Microwave Background radiation and the peak of the cosmic FIRB radiation;Fermi coupling parameter and coupling parameters of the proposed Super-Weak and Extremely-Weak interactions. Additionally, WUM forecasts the masses of dark matter particles, axions, and neutrinos;proposes two fundamental parameters of the World: fine-structure constant α and the quantity Q which is the dimensionless value of the fifth coordinate, and three fundamental physical units: basic unit of momentum, energy density, and energy flux density. WUM suggests that all time-dependent parameters of the World are inter- connected and in fact dependent on Q. We recommend adding the quantity Q to the list of the CODATA-recommended values.展开更多
The neutrino burst detected during supernova SN 1987A is explained in a strangeon star model, in which it is proposed that a pulsar-like compact object is composed of strangeons （strangeon： an abbreviation for ＂str...The neutrino burst detected during supernova SN 1987A is explained in a strangeon star model, in which it is proposed that a pulsar-like compact object is composed of strangeons （strangeon： an abbreviation for ＂strange nucleon＂）. A nascent strangeon star＇s initial internal energy is calculated, with the inclusion of pion excitation （energy around 1053 erg, comparable to the gravitational binding energy of a collapsed core）. A liquid-solid phase transition at temperature - 1 - 2 MeV may occur only a few tens of seconds after core collapse, and the thermal evolution of a strangeon star is then modeled. It is found that the neutrino burst observed from SN 1987A can be reproduced in such a cooling model.展开更多
Heavy neutrinos can be discovered at LHC. Many extensions for Standard Model predict the existence of a new neutrino which has a mass at high energies. B-L model is one of them which predict the existence of three hea...Heavy neutrinos can be discovered at LHC. Many extensions for Standard Model predict the existence of a new neutrino which has a mass at high energies. B-L model is one of them which predict the existence of three heavy (right-handed) neutrinos one per generation, new gauge massive boson and a new scalar Higgs boson which is different from the SM Higgs. In the present work we search for heavy neutrino in 4 leptons + missing energy final state events which are produced in proton-proton collisions at LHC using data produced from Monte Carlo simulation using B-L model at different center of mass energies. We predict that the heavy neutrinos pairs can be produced from new gauge neutral massive boson decay and then the heavy neutrino pairs can decay to 4 leptons + missing energy final state which give us an indication for new signature of new physics beyond Standard Model at higher energies at LHC.展开更多
Supernova （SN） neutrinos detected on the Earth are subject to the shock wave effects, the Mikheyev- Smirnov-Wolfenstein （MSW） effects, the neutrino collective effects and the Earth matter effects. Considering the ...Supernova （SN） neutrinos detected on the Earth are subject to the shock wave effects, the Mikheyev- Smirnov-Wolfenstein （MSW） effects, the neutrino collective effects and the Earth matter effects. Considering the recent experimental result about the large mixing angle 013 （-8.8°） provided by the Daya Bay Collaboration and applying the available knowledge for the neutrino conversion probability in the high resonance region of SN, PH , which is in the form of hypergeometric function in the case of large 813, we deduce the expression of PH taking into account the shock wave effects. It is found that PH is not zero in a certain range of time due to the shock wave effects. After considering all the four physical effects and scanning relevant parameters, we calculate the event numbers of SN neutrinos for the ＂Garehing＂ distribution of neutrino energy spectrum. From the numerical results, it is found that the behaviors of neutrino event numbers detected on the Earth depend on the neutrino mass hierarchy and neutrino spectrum parameters including the dimensionless pinching parameter βa （where a refers to neutrino flavor）, the average energy 〈Ea〉, and the SN neutrino luminosities La. Finally, we give the ranges of SN neutrino event numbers that will be detected at the Daya Bay experiment.展开更多
The neutrinos of the early universe evolved from a relativistic phase at very early times to a massive particle behavior at later times.First,the kinetic energy of neutrinos is relativistic,and as a result,neutrinos c...The neutrinos of the early universe evolved from a relativistic phase at very early times to a massive particle behavior at later times.First,the kinetic energy of neutrinos is relativistic,and as a result,neutrinos can be described as massless particles.As the Universe expands,the temperature drops and the kinetic energy decreases,and the neutrinos turn into a non-relativistic phase with a non-negligible mass.In this paper,we first put constraints on the total mass of neutrinos.Then we investigate the effect of neutrinos on the CMB power spectrum,P(k),in the case of massless and massive neutrinos using the publicly available Boltzmann code CAMB and we prove that when neutrino coupled to scalar field the CMB power spectrum has a little shift,which means that the power spectrum of CMB is greatly affected by the background energy density and the accelerated expansion of the Universe.Furthermore,we investigate the effect of perturbed quintessence on this spectrum and find that the highest peaks of this spectrum are shifted to smaller scales.Also,we estimate the Deceleration-Acceleration(DA)redshift transition(z_(da))using the coupling canonical scalar field with neutrinos.For Pantheon data we obtain z_(da)=0.7±0.05 and for CC data z_(da)=0.68±0.03.In the presence of neutrinos the DA redshift transition is z_(da)=0.42±0.03 for Pantheon data and z_(da)=0.49±0.05 for CC data.These results indicate that neutrinos can affect this phase transition.The results obtained in this article show that when the mass of neutrinos increases,the value of the background energy density increases,resulting in a higher power spectrum peak.Also,by examining the effect of coupling neutrinos to dark energy,we find that the transition occurs at lower redshift.展开更多
As a unique probe,the precision measurement of pp solar neutrinos is important for studying the sun’s energy mechanism as it enables monitoring the thermodynamic equilibrium and studying neutrino oscillations in the ...As a unique probe,the precision measurement of pp solar neutrinos is important for studying the sun’s energy mechanism as it enables monitoring the thermodynamic equilibrium and studying neutrino oscillations in the vacuum-dominated region.For a large-scale liquid scintillator detector,a bottleneck for pp solar neutrino detection is the pile-up events of intrinsic14C decay.This paper presents a few approaches to discriminating between pp solar neutrinos and ^(14)C pile-up events by considering the differences in their time and spatial distributions.In this study,a Geant4-based Monte Carlo simulation is conducted.Multivariate analysis and deep learning technology are adopted to investigate the capability of ^(14)C pile-up reduction.The BDTG (boosted decision trees with gradient boosting) model and VGG network demonstrate good performance in discriminating pp solar neutrinos and ^(14)C double pile-up events.Under the ^(14)C concentration assumption of 5×10-18g/g,the signal significance can achieve 10.3 and 15.6 using the statistics of only one day.In this case,the signal efficiency for discrimination using the BDTG model while rejecting 99.18% ^(14)C double pile-up events is 51.1%,and that for the case where the VGG network is used while rejecting 99.81%of the ^(14)C double pile-up events is 42.7%.展开更多
In this paper we investigate the evolution of the cosmology model with dark energy interacting with massive neutrinos and dark matter. Using the numerical method to investigate the dynamical system, we find that the s...In this paper we investigate the evolution of the cosmology model with dark energy interacting with massive neutrinos and dark matter. Using the numerical method to investigate the dynamical system, we find that the stronger the interaction between dark energy and dark matter, the lower the ratio of dark matter in the universe is; also, the stronger the interaction between dark energy and massive neutrinos, the lower the ratio of massive neutrinos in the universe is. On the other hand, the interaction between dark energy and dark matter or massive neutrinos has an effect on disturbing the universe＇s acceleration; we also find that our universe is still accelerating.展开更多
We constrain the neutrino mass in f(R) gravity using the latest observations from the Planck, BAO and BICEP2 data. We find that the measurement on the B-modes can break the degeneracy between the massive neutrinos and...We constrain the neutrino mass in f(R) gravity using the latest observations from the Planck, BAO and BICEP2 data. We find that the measurement on the B-modes can break the degeneracy between the massive neutrinos and the f(R) gravity. We find a non-zero value of the Compton wavelengths B0 at a 68% confidence level for the f(R) model in the presence of massive neutrinos when the BICEP2 data is used. Furthermore, the tension on the tensor-to-scalar ratios between the measured values from Plank and BICEP2 is significantly reconciled in our model.展开更多
A new physics scenario to explain PeV neutrinos observed in the IceCube experiment is introduced,with dark matter and dark energy considered.A slowly decaying very heavy fermion with a Pe V mass as the dark matter par...A new physics scenario to explain PeV neutrinos observed in the IceCube experiment is introduced,with dark matter and dark energy considered.A slowly decaying very heavy fermion with a Pe V mass as the dark matter particle is the origin of the PeV neutrinos.They couple to an extremely light field and this light field constitutes the dark energy.展开更多
The potential cosmological and astrobiological implications of neutrinos are considered. Dark energy drives the current phase of accelerating cosmic expansion. Like inflation, it may decay in time to matter and radiat...The potential cosmological and astrobiological implications of neutrinos are considered. Dark energy drives the current phase of accelerating cosmic expansion. Like inflation, it may decay in time to matter and radiation. However, since its energy density is minuscule in comparison, decay would be unlikely to inject such a rich variety of particles into the universe, and may instead be limited to the lowest energy fermions. Nonrelativistic neutrinos have the capacity to form stable, galaxy-engulfing haloes supported by degeneracy pressure, much like white dwarves and neutron stars. Conversely, bodies of mass can indefinitely rely on Coulomb forces for weight support. Opportunities for the mutual annihilation of electron neutrinos are largely confined to planets containing iron in the hcp phase. If dark energy decays primarily to neutrinos in 40 ~ 100 Gyr, then oceanic planets orbiting within the resulting haloes could provide long-term habitats for aquatic life with only lax constraints on the neutrino mass, . Various considerations now favour the possibility that neutrinos are Majorana particles with an inverted mass hierarchy and an electron neutrino mass in the vicinity of 50 meV. Sterile neutrinos of eV-mass may already be a significant component of dark matter, and could enhance planetary heating when active neutrino haloes become heavily depleted. An intriguing mechanism capable of regulating oceanic heat flux over a wide range of planetary masses is also described.展开更多
Solar, atmospheric and reactor neutrino experiments established that neutrinos are massive. It is quite natural then to consider neutrinos as candidate particles for explaining the dark matter in halos around galaxies...Solar, atmospheric and reactor neutrino experiments established that neutrinos are massive. It is quite natural then to consider neutrinos as candidate particles for explaining the dark matter in halos around galaxies. We study the gravitational clustering of these neutrinos within a model of a massive core and a surrounding spherical neutrino halo. The neutrinos form a degenerate Fermi gas and a loaded polytropic equation is established. We solve the equation and we obtain the neutrino density in a galaxy, the size of the galaxy and the galactic rotational curves. The available data favor a neutrino with a mass around 10 eV. The consequent cosmological implications are examined.展开更多
In this article an idea is presented, which allows for the explanation of superluminal muon neutrinos. It is based on the introduction of a new superluminal, massless gauge boson coupling to the neutrino only, but not...In this article an idea is presented, which allows for the explanation of superluminal muon neutrinos. It is based on the introduction of a new superluminal, massless gauge boson coupling to the neutrino only, but not to other standard model particles. The model is discussed with regard to the Supernova 1987 (SN 1987) velocity bound on electron antineutrinos and the Cohen-Glashow constraint on superluminal neutrino propagation. The latter can be circumvented if— within the framework of the model—a sterile neutrino mixing with the active neutrino mass eigenstates is introduced. The suggestion of a sterile neutrino accounting for superluminal neutrinos has already been proposed in several papers. It is possible to choose mixing angles with the sterile neutrino sector such that the model respects both the SN 1987 bound and the muon neutrino travels superluminally.展开更多
The constraints on the number of neutrinos generations, g'1 coupling and Z?- Z′ mixing angle through the invisible width method, and in the framework of a U(1)B-L model are obtained. Based on the experimental val...The constraints on the number of neutrinos generations, g'1 coupling and Z?- Z′ mixing angle through the invisible width method, and in the framework of a U(1)B-L model are obtained. Based on the experimental value reported by the LEP for the rate , we obtained a bound on the g'1 coupling, . In addition, we derive 90% C.L. bounds on the Z?- Z′ mixing angle , improving the existing bounds by one order of magnitude.展开更多
It is generally believed that young, rapidly rotating pulsars are important sites of particle acceleration, in which protons can be accelerated to relativistic energy above the polar cap region if the magnetic moment ...It is generally believed that young, rapidly rotating pulsars are important sites of particle acceleration, in which protons can be accelerated to relativistic energy above the polar cap region if the magnetic moment is antiparallel to the spin axis （μ·Ω 〈 0）. To obtain diffuse neutrinos and gamma-rays at TeV that originate in our Galaxy, we use the Monte Carlo method to generate a sample of young pulsars with ages less than 106 yr in our galaxy; the neutrinos and high-energy gamma-rays can be produced through a photomeson process with the interaction of energetic protons and soft X-ray photons （p ＋γ→△＋→n＋π＋/p＋π0） for a single pulsar, and these X-ray photons come from the surface of the neutron star. The results suggest that the flux of diffuse neutrinos at TeV energies is lower than the background flux, indicating they are difficult to detect using current neutrino telescopes.展开更多
A new era in particle physics is being spurred on by new data from the Large Hadron Collider. Non-vanishing neutrino masses represent firm observational evidence of new physics beyond the Standard Model. An extension ...A new era in particle physics is being spurred on by new data from the Large Hadron Collider. Non-vanishing neutrino masses represent firm observational evidence of new physics beyond the Standard Model. An extension of the latter, based on a SU(3)C × SU(2)L × U(1)Y × U(1)B-L symmetry, incorporating an established Baryon minus Lepton number invariance, is proposed as a viable and testable solution to the neutrino mass problem. We argue that LHC data will probe all the new content of this model: heavy neutrinos, an extra gauge boson emerging from spontaneous breaking of the additional gauge group at the TeV scale, onset by a new heavier Higgs boson, also visible at the CERN proton-proton collider. An even more exciting version of this model is the one exploiting Supersymmetry: firstly, it incurporates all its well-known benefits;secondly, it alleviates the flaws of its more minimal realisations. Finally, this model provides a credible cold Dark Matter candidate, the lightest sneutrino, detectable in both underground and collider experiments.展开更多
Based on parity violation in the weak interaction and evidences from neutrino oscillation, a natural choice is that neutrinos may be superluminal particles with tiny mass. To keep causality for Superluminal particles,...Based on parity violation in the weak interaction and evidences from neutrino oscillation, a natural choice is that neutrinos may be superluminal particles with tiny mass. To keep causality for Superluminal particles, a kinematic time under a non-standard form of the Lorentz transformation is introduced. A Dirac-type equation for Superluminal neutrinos is further investigated, and its solution is brief discussed. This equation can be written in two spinor equations coupled together via tiny mass while respecting maximum parity violation. As a consequence, parity violation implies that the principle of relativity is violated in the weak interaction.展开更多
In the middle of May,2017,Professor Ar thur B.McDonald,director of the Sudbury Neutrino Observatory(SNO)in Canada and Nobel Prize Laureate in Physics in 2015,visited the Institute of High Energy Physics(IHEP),Chinese ...In the middle of May,2017,Professor Ar thur B.McDonald,director of the Sudbury Neutrino Observatory(SNO)in Canada and Nobel Prize Laureate in Physics in 2015,visited the Institute of High Energy Physics(IHEP),Chinese Academy of Sciences(CAS).After a brief visit to the laboratories for particle physics at IHEP,he shared his opinions on the future of neutrino physics,neutr ino exper iments,and other large scienti f ic faci l ities in China and worldwide.展开更多
基金supported by the National Natural Science Foundation of China under Grant Nos.12305069,11947022,12473001,11975072,11875102,and 11835009the National SKA Program of China under Grants Nos.2022SKA0110200 and 2022SKA0110203+1 种基金the Program of the Education Department of Liaoning Province under Grant No.JYTMS20231695the National 111 Project under Grant No.B16009。
文摘Sterile neutrinos can influence the evolution of the Universe,and thus cosmological observations can be used to detect them.Future gravitational-wave(GW)observations can precisely measure absolute cosmological distances,helping to break parameter degeneracies generated by traditional cosmological observations.This advancement can lead to much tighter constraints on sterile neutrino parameters.This work provides a preliminary forecast for detecting sterile neutrinos using third-generation GW detectors in combination with future shortγ-ray burst observations from a THESEUS-like telescope,an approach not previously explored in the literature.Both massless and massive sterile neutrinos are considered within theΛCDM cosmology.We find that using GW data can greatly enhance the detection capability for massless sterile neutrinos,reaching 3σlevel.For massive sterile neutrinos,GW data can also greatly assist in improving the parameter constraints,but it seems that effective detection is still not feasible.
文摘It is the current belief of the Physics Community that neutrinos are bereft of Charge because of Conservation of Charge in decay processes such as Beta Decay and are point particles with no physical size or shape. It is the purpose of this paper to calculate the charges and the size of the electron neutrino, the muon neutrino, and the tau neutrino based on data available of their rest masses using the charges and rest masses of the electron, muon, and tau leptons from the Standard Model of Particle Physics Table. We base our calculations on the premise that Energy can create both Mass and Charge. Charge by itself is not conserved in any process that produces neutrinos. Only Total Energy is conserved.
文摘Reliable observations find only three neutrino mass eigenstates, oscillating between each other as neutrinos travel through space, and limit the sum of the three neutrino masses. At a minimum, any reliable description of neutrinos must allow only three neutrino mass eigenstates and predict a neutrino mass sum consistent with observations. This paper describes neutrinos as spheres, with radius one quarter of their Compton wavelength and thickness of the Planck length, surrounding a central core along their rotation axis, with diameter of the Planck length. This description of neutrinos as excitations of the vacuum energy allows only three neutrino mass eigenstates and predicts a neutrino mass sum consistent with observations.
文摘In this manuscript we discuss mass-varying neutrinos and propose their energy density to exceed that of baryonic and dark matter. We introduce cosmic Large Grains whose mass is about Planck mass, and their temperature is around 29 K. Large Grains are in fact Bose-Einstein condensates of proposed dineutrinos, and are responsible for the cosmic Far-Infrared Background (FIRB) radiation. The distribution of the energy density of all components of the World (protons, electrons, photons, neutrinos, and dark matter particles) is considered. We present an overview of the World- Universe Model (WUM) and pay particular attention to the self-consistent set of time-varying values of basic parameters of the World: the age and critical energy density;Newtonian parameter of gravitation and Hubble’s parameter;temperatures of the cosmic Microwave Background radiation and the peak of the cosmic FIRB radiation;Fermi coupling parameter and coupling parameters of the proposed Super-Weak and Extremely-Weak interactions. Additionally, WUM forecasts the masses of dark matter particles, axions, and neutrinos;proposes two fundamental parameters of the World: fine-structure constant α and the quantity Q which is the dimensionless value of the fifth coordinate, and three fundamental physical units: basic unit of momentum, energy density, and energy flux density. WUM suggests that all time-dependent parameters of the World are inter- connected and in fact dependent on Q. We recommend adding the quantity Q to the list of the CODATA-recommended values.
基金supported by the National Natural Science Foundation of China(11673002,U1531243 and 11373011)the Strategic Priority Research Program of CAS(No.XDB23010200)
文摘The neutrino burst detected during supernova SN 1987A is explained in a strangeon star model, in which it is proposed that a pulsar-like compact object is composed of strangeons （strangeon： an abbreviation for ＂strange nucleon＂）. A nascent strangeon star＇s initial internal energy is calculated, with the inclusion of pion excitation （energy around 1053 erg, comparable to the gravitational binding energy of a collapsed core）. A liquid-solid phase transition at temperature - 1 - 2 MeV may occur only a few tens of seconds after core collapse, and the thermal evolution of a strangeon star is then modeled. It is found that the neutrino burst observed from SN 1987A can be reproduced in such a cooling model.
文摘Heavy neutrinos can be discovered at LHC. Many extensions for Standard Model predict the existence of a new neutrino which has a mass at high energies. B-L model is one of them which predict the existence of three heavy (right-handed) neutrinos one per generation, new gauge massive boson and a new scalar Higgs boson which is different from the SM Higgs. In the present work we search for heavy neutrino in 4 leptons + missing energy final state events which are produced in proton-proton collisions at LHC using data produced from Monte Carlo simulation using B-L model at different center of mass energies. We predict that the heavy neutrinos pairs can be produced from new gauge neutral massive boson decay and then the heavy neutrino pairs can decay to 4 leptons + missing energy final state which give us an indication for new signature of new physics beyond Standard Model at higher energies at LHC.
基金Supported by the National Natural Science Foundation of China under Grant Nos.10975018,11175020,11275025,and 11205185the Fundamental Research Funds for the Central Universities in China
文摘Supernova （SN） neutrinos detected on the Earth are subject to the shock wave effects, the Mikheyev- Smirnov-Wolfenstein （MSW） effects, the neutrino collective effects and the Earth matter effects. Considering the recent experimental result about the large mixing angle 013 （-8.8°） provided by the Daya Bay Collaboration and applying the available knowledge for the neutrino conversion probability in the high resonance region of SN, PH , which is in the form of hypergeometric function in the case of large 813, we deduce the expression of PH taking into account the shock wave effects. It is found that PH is not zero in a certain range of time due to the shock wave effects. After considering all the four physical effects and scanning relevant parameters, we calculate the event numbers of SN neutrinos for the ＂Garehing＂ distribution of neutrino energy spectrum. From the numerical results, it is found that the behaviors of neutrino event numbers detected on the Earth depend on the neutrino mass hierarchy and neutrino spectrum parameters including the dimensionless pinching parameter βa （where a refers to neutrino flavor）, the average energy 〈Ea〉, and the SN neutrino luminosities La. Finally, we give the ranges of SN neutrino event numbers that will be detected at the Daya Bay experiment.
文摘The neutrinos of the early universe evolved from a relativistic phase at very early times to a massive particle behavior at later times.First,the kinetic energy of neutrinos is relativistic,and as a result,neutrinos can be described as massless particles.As the Universe expands,the temperature drops and the kinetic energy decreases,and the neutrinos turn into a non-relativistic phase with a non-negligible mass.In this paper,we first put constraints on the total mass of neutrinos.Then we investigate the effect of neutrinos on the CMB power spectrum,P(k),in the case of massless and massive neutrinos using the publicly available Boltzmann code CAMB and we prove that when neutrino coupled to scalar field the CMB power spectrum has a little shift,which means that the power spectrum of CMB is greatly affected by the background energy density and the accelerated expansion of the Universe.Furthermore,we investigate the effect of perturbed quintessence on this spectrum and find that the highest peaks of this spectrum are shifted to smaller scales.Also,we estimate the Deceleration-Acceleration(DA)redshift transition(z_(da))using the coupling canonical scalar field with neutrinos.For Pantheon data we obtain z_(da)=0.7±0.05 and for CC data z_(da)=0.68±0.03.In the presence of neutrinos the DA redshift transition is z_(da)=0.42±0.03 for Pantheon data and z_(da)=0.49±0.05 for CC data.These results indicate that neutrinos can affect this phase transition.The results obtained in this article show that when the mass of neutrinos increases,the value of the background energy density increases,resulting in a higher power spectrum peak.Also,by examining the effect of coupling neutrinos to dark energy,we find that the transition occurs at lower redshift.
基金supported by National Natural Science Foundation of China(No.12005044)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA10011200)Guangxi Science and Technology Program(No.GuiKeAD21220037).
文摘As a unique probe,the precision measurement of pp solar neutrinos is important for studying the sun’s energy mechanism as it enables monitoring the thermodynamic equilibrium and studying neutrino oscillations in the vacuum-dominated region.For a large-scale liquid scintillator detector,a bottleneck for pp solar neutrino detection is the pile-up events of intrinsic14C decay.This paper presents a few approaches to discriminating between pp solar neutrinos and ^(14)C pile-up events by considering the differences in their time and spatial distributions.In this study,a Geant4-based Monte Carlo simulation is conducted.Multivariate analysis and deep learning technology are adopted to investigate the capability of ^(14)C pile-up reduction.The BDTG (boosted decision trees with gradient boosting) model and VGG network demonstrate good performance in discriminating pp solar neutrinos and ^(14)C double pile-up events.Under the ^(14)C concentration assumption of 5×10-18g/g,the signal significance can achieve 10.3 and 15.6 using the statistics of only one day.In this case,the signal efficiency for discrimination using the BDTG model while rejecting 99.18% ^(14)C double pile-up events is 51.1%,and that for the case where the VGG network is used while rejecting 99.81%of the ^(14)C double pile-up events is 42.7%.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10873004)the Scientific Research Fund of Hunan Provincial Education Department (Grant No. 08B051)+1 种基金the Program for Excellent Talents in Hunan Normal Universitythe State Key Development Program for Basic Research Program of China (Grant No. 2010CB832800)
文摘In this paper we investigate the evolution of the cosmology model with dark energy interacting with massive neutrinos and dark matter. Using the numerical method to investigate the dynamical system, we find that the stronger the interaction between dark energy and dark matter, the lower the ratio of dark matter in the universe is; also, the stronger the interaction between dark energy and massive neutrinos, the lower the ratio of massive neutrinos in the universe is. On the other hand, the interaction between dark energy and dark matter or massive neutrinos has an effect on disturbing the universe＇s acceleration; we also find that our universe is still accelerating.
基金Supported by the Italian Space Agency(ASI),Through Contract Agreement I/023/12/0
文摘We constrain the neutrino mass in f(R) gravity using the latest observations from the Planck, BAO and BICEP2 data. We find that the measurement on the B-modes can break the degeneracy between the massive neutrinos and the f(R) gravity. We find a non-zero value of the Compton wavelengths B0 at a 68% confidence level for the f(R) model in the presence of massive neutrinos when the BICEP2 data is used. Furthermore, the tension on the tensor-to-scalar ratios between the measured values from Plank and BICEP2 is significantly reconciled in our model.
基金support from the National Natural Science Foundation of China(Nos.11875306 and 12275335)。
文摘A new physics scenario to explain PeV neutrinos observed in the IceCube experiment is introduced,with dark matter and dark energy considered.A slowly decaying very heavy fermion with a Pe V mass as the dark matter particle is the origin of the PeV neutrinos.They couple to an extremely light field and this light field constitutes the dark energy.
文摘The potential cosmological and astrobiological implications of neutrinos are considered. Dark energy drives the current phase of accelerating cosmic expansion. Like inflation, it may decay in time to matter and radiation. However, since its energy density is minuscule in comparison, decay would be unlikely to inject such a rich variety of particles into the universe, and may instead be limited to the lowest energy fermions. Nonrelativistic neutrinos have the capacity to form stable, galaxy-engulfing haloes supported by degeneracy pressure, much like white dwarves and neutron stars. Conversely, bodies of mass can indefinitely rely on Coulomb forces for weight support. Opportunities for the mutual annihilation of electron neutrinos are largely confined to planets containing iron in the hcp phase. If dark energy decays primarily to neutrinos in 40 ~ 100 Gyr, then oceanic planets orbiting within the resulting haloes could provide long-term habitats for aquatic life with only lax constraints on the neutrino mass, . Various considerations now favour the possibility that neutrinos are Majorana particles with an inverted mass hierarchy and an electron neutrino mass in the vicinity of 50 meV. Sterile neutrinos of eV-mass may already be a significant component of dark matter, and could enhance planetary heating when active neutrino haloes become heavily depleted. An intriguing mechanism capable of regulating oceanic heat flux over a wide range of planetary masses is also described.
文摘Solar, atmospheric and reactor neutrino experiments established that neutrinos are massive. It is quite natural then to consider neutrinos as candidate particles for explaining the dark matter in halos around galaxies. We study the gravitational clustering of these neutrinos within a model of a massive core and a surrounding spherical neutrino halo. The neutrinos form a degenerate Fermi gas and a loaded polytropic equation is established. We solve the equation and we obtain the neutrino density in a galaxy, the size of the galaxy and the galactic rotational curves. The available data favor a neutrino with a mass around 10 eV. The consequent cosmological implications are examined.
文摘In this article an idea is presented, which allows for the explanation of superluminal muon neutrinos. It is based on the introduction of a new superluminal, massless gauge boson coupling to the neutrino only, but not to other standard model particles. The model is discussed with regard to the Supernova 1987 (SN 1987) velocity bound on electron antineutrinos and the Cohen-Glashow constraint on superluminal neutrino propagation. The latter can be circumvented if— within the framework of the model—a sterile neutrino mixing with the active neutrino mass eigenstates is introduced. The suggestion of a sterile neutrino accounting for superluminal neutrinos has already been proposed in several papers. It is possible to choose mixing angles with the sterile neutrino sector such that the model respects both the SN 1987 bound and the muon neutrino travels superluminally.
文摘The constraints on the number of neutrinos generations, g'1 coupling and Z?- Z′ mixing angle through the invisible width method, and in the framework of a U(1)B-L model are obtained. Based on the experimental value reported by the LEP for the rate , we obtained a bound on the g'1 coupling, . In addition, we derive 90% C.L. bounds on the Z?- Z′ mixing angle , improving the existing bounds by one order of magnitude.
基金partially supported by the Science Research Foundation Department of Education+1 种基金 Yunnan Province (Grant No. 2012Y316)Yunnan Province under Grant No. 2010CD112
文摘It is generally believed that young, rapidly rotating pulsars are important sites of particle acceleration, in which protons can be accelerated to relativistic energy above the polar cap region if the magnetic moment is antiparallel to the spin axis （μ·Ω 〈 0）. To obtain diffuse neutrinos and gamma-rays at TeV that originate in our Galaxy, we use the Monte Carlo method to generate a sample of young pulsars with ages less than 106 yr in our galaxy; the neutrinos and high-energy gamma-rays can be produced through a photomeson process with the interaction of energetic protons and soft X-ray photons （p ＋γ→△＋→n＋π＋/p＋π0） for a single pulsar, and these X-ray photons come from the surface of the neutron star. The results suggest that the flux of diffuse neutrinos at TeV energies is lower than the background flux, indicating they are difficult to detect using current neutrino telescopes.
文摘A new era in particle physics is being spurred on by new data from the Large Hadron Collider. Non-vanishing neutrino masses represent firm observational evidence of new physics beyond the Standard Model. An extension of the latter, based on a SU(3)C × SU(2)L × U(1)Y × U(1)B-L symmetry, incorporating an established Baryon minus Lepton number invariance, is proposed as a viable and testable solution to the neutrino mass problem. We argue that LHC data will probe all the new content of this model: heavy neutrinos, an extra gauge boson emerging from spontaneous breaking of the additional gauge group at the TeV scale, onset by a new heavier Higgs boson, also visible at the CERN proton-proton collider. An even more exciting version of this model is the one exploiting Supersymmetry: firstly, it incurporates all its well-known benefits;secondly, it alleviates the flaws of its more minimal realisations. Finally, this model provides a credible cold Dark Matter candidate, the lightest sneutrino, detectable in both underground and collider experiments.
文摘Based on parity violation in the weak interaction and evidences from neutrino oscillation, a natural choice is that neutrinos may be superluminal particles with tiny mass. To keep causality for Superluminal particles, a kinematic time under a non-standard form of the Lorentz transformation is introduced. A Dirac-type equation for Superluminal neutrinos is further investigated, and its solution is brief discussed. This equation can be written in two spinor equations coupled together via tiny mass while respecting maximum parity violation. As a consequence, parity violation implies that the principle of relativity is violated in the weak interaction.
文摘In the middle of May,2017,Professor Ar thur B.McDonald,director of the Sudbury Neutrino Observatory(SNO)in Canada and Nobel Prize Laureate in Physics in 2015,visited the Institute of High Energy Physics(IHEP),Chinese Academy of Sciences(CAS).After a brief visit to the laboratories for particle physics at IHEP,he shared his opinions on the future of neutrino physics,neutr ino exper iments,and other large scienti f ic faci l ities in China and worldwide.
