Distinguishable RGE Running Effects Between Dirac Neutrinos and Majorana Neutrinos with Vanishing Majorana CP-Violating Phases

In a novel parametrization of neutrino mixing and in the approximation of т-lepton dominance, we show that the one-loop renormalization-group equations (RGEs) of Dirac neutrinos are different from those of Majorana neutrinos even if two Majorana CP-violating phases vanish. As the latter can keep vanishing from the electroweak scale to the typical seesaw scale, it makes sense to distinguish between the RGE running effects of neutrino mixing parameters in Dirac and Majorana cases. The differences are found to be quite large in the minimal supersymmetric standard model with sizable tanβ, provided the masses of three neutrinos are nearly degenerate or have an inverted hierarchy.     

Distinguishable RGE Running Effects Between Dirac Neutrinos and Majorana Neutrinos with Vanishing Majorana CP-Violating Phases

In a novel parametrization of neutrino mixing and in the approximation of τ-lepton dominance, we show that the one-loop renormalization-group equations （RGEs） of Dirac neutrinos are different from those of Majorana neutrinos even if two Majorana CP-violating phases vanish. As the latter can keep vanishing from the electroweak scale to the typical seesaw scale, it makes sense to distinguish between the RGE running effects of neutrino mixing parameters in Dirac and Majorana cases. The differences are found to be quite large in the minimal supersymmetric standard model with sizable tan β, provided the masses of three neutrinos are nearly degenerate or have an inverted hierarchy.     

Singletons and Neutrinos

The first half is a rapid review of 30 years of work on physics in anti-de Sitter space, with heavy emphasis on singletons. Principal topics are the kinematical basis for regarding singletons as the constituents of massless particles, and the effect of (negative) curvature in the infrared domain. Ideas that lead to an alternative to Big Bang cosmology are merely sketched. The second half presents new ideas inspired by experimental results on neutrino oscillations. Since leptons are massless before symmetry breaking it is natural to view them as composite states consisting of one Bose singleton (the Rac) and one Fermi singleton (the Di). This gives rise to a particular formulation of the phenomenology of electroweak physics, and strong suggestions for an expansion of the Standard Model. An expansion of the Higgs sector seems inevitable, and flavor changing symmetry, complete with a new set of heavy vector mesons, is a very attractive possibility.     

Muon与Tau中微子的运动学有效质量及其不可探测性

利用最新的WMAP观测数据推导出电子、Muon和Tau中微子的运动学有效质量的一般上限:e2+μ2+τ2=m12+m22+m32<0.5eV2,或α<0.71eV(其中α=e,μ,τ)。考虑现有中微子振荡的实验数据,进一步得到e<0.24eV以及μ≈τ<0.24eV. 因此有效质量_μ和_τ太小而无法被探测.     

Oscillations Do Not Distinguish Between Massive and Tachyonic Neutrinos

It is shown that the hypothesis of tachyonic neutrinos leads to the same oscillations effect as if they were usual massive particles. Therefore, the experimental evidence of neutrino oscillations does not distinguish between massive and tachyonic neutrinos. Thus, in view of the fact that the results of the direct neutrino mass measurements are not decisive, the question about the nature of neutrinos remains still open.     

Nuclear Responses for Neutrinos and Mo Observatory of Neutrinos

Nuclear responses for neutrinos and neutrino studies in Mo nuclei are briefly reported. Nuclear spin-isospin responses for neutrinos are crucial for neutrino studies in nuclei. Spin-isospin responses for solar neutrinos, supernova neutrinos and neutrinos involved in double-beta decays are discussed. It is of great interest to study neutrino masses and low energy solar neutrinos. It is shown that it is possible to carry out with ¹⁰⁰Mo both spectroscopic studies of double-beta decays with the sensitivity of the order of m 0.03eV and real-time exclusive studies of the low energy solar neutrinos.     

Search for Cold Dark Matter and Solar Neutrinos with GENIUS and GENIUS-TF

The new project GENIUS will cover a wide range of the parameter space of predictions of SUSY for neutralinos as cold dark matter. Further it has the potential to be a real-time detector for low-energy (pp and ⁷Be) solar neutrinos. A GENIUS Test Facility has been funded and will come into operation by early 2003.     

Neutrinos in a Vacuum Dominated Cosmology

We explore the dynamics of neutrinos in a vacuum dominated cosmology. First we show that such a geometry will induce a phase change in the eigenstates of a massive neutrino and we calculate the phase change. We also calculate the delay in the neutrino flight times in this geometry. Applying our results to the presently observed background vacuum energy density, we find that for neutrino sources further than 1.5 Gpc away both effects become non-trivial, being of the order of the standard relativistic corrections. Such sources are within the observable Hubble Deep Field. The results which are theoretically interesting are also potentially useful, in the future, as detection techniques improve. For example such effects on neutrinos from distant sources like supernovae could be used, in an independent method alternative to standard candles, to constrain the dark energy density and the deceleration parameter. The discussion is extended to investigate Caianiello's inertial or maximal acceleration (MA) effects of such a vacuum dominated spacetime on neutrino oscillations. Assuming that the MA phenomenon exists, we find that its form as generated by the presently observed vacuum energy density would still have little or no measurable effect on neutrino phase evolution, for neutrinos in the energy range of a few eV.     

Muon Anomalous Magnetic Moment in the Supersymmetric Models with and Without Right—Handed Neutrinos

We discuss the anomalous magnetic moment of muon in the minimal supersymmetric model with and without right-handed neutrinos.In the same framework,the decay width of τ→μγ is also evaluated.Considering the measured g-2 value of muon in the E821 experiment and other experimental constraints on the lepton-flavor-violation processes,we carry out numerical analysis on the concerned observables in the minimal supergravity scenario.     

Equation of State of Protoneutron Star with Trapped Neutrinos

The influence of trapped neutrinos on the proto-neutron star is studied in the framework of relativistic mean-field theory. The results show that trapped neutrinos increase proton fraction and make the equation of ๏๏ state of neutron star matter softer when neglecting hyperonic freedom, while suppress the appearance of hyperons and make the equation of state stiffer when including hyperons in the protoneutron star. The maximum mass, compared with cold neutron star which is in beta equilibrium, decreases by 0.06_{M_{\odot}} for non-strange protoneutron star while increases by 0.21_{M_{\odot}} for protoneutron star with hyperons when the relative number of trapped neutrino is 0.4.     

强和弱Y-Y相互作用下的奇异强子物质

把修正的夸克-介子耦合模型推广到包含奇异性的情形， 并用来研究奇异强子物质的状态方程. 从最新的6ΛΛHe双超核的实验导出的弱Λ Λ相互作用和过去采用的强Λ Λ相互作用同时被用于计算. 比较发现， 具有强Λ-Λ相互作用的系统束缚得比正常核物质要紧， 而具有弱Λ Λ相互作用的系统则比正常核物质束缚得要松得多. 无论强还是弱相互作用情况， 为了合适地描述修正的夸克 介子耦合模型中超子-超子（Y Y）相互作用， 必须引进σ*和介子. A modified quark meson coupling (MQMC) model is extended to include Λ hyperons and Ξ hyperons. The extended model is then used to study the equation of state (EOS) for strange hadronic matter. A weak Λ Λ interaction deduced from recent observation of 6ΛΛHe double hypernucleus is adopted in the calculation. The resultant EOS is compared with that deduced from a strong Λ Λ interaction. It is found that while the system with the strong ΛΛ interaction is more deeply bound than ordinary nuclear matter due to the opening of new degrees of freedom， the system with the weak Λ Λ interaction is rather loosely bound compared to the later. It is necessary to introduce the strange mesons σ*and in the MQMC model to describe properly the interaction between the hyperons in either strong or weak ΛΛ interaction case.     

Singletons,Physics in AdS Universe and Oscillations of Composite Neutrinos

The study starts with the kinematical aspects of singletons and massless particles. It extends to the beginning of a field theory of composite elementary particles and its relations with conformal field theory, including very recent developments and speculations about a possible interpretation of neutrino oscillations and CP violation in this context. This framework was developed during the past twenty years. Based on our deformation philosophy of physical theories, it deals with elementary particles composed of singletons in anti-De Sitter spacetime.     

Gamma-Rays and Neutrinos from Proton-Proton Interactions in Gamma-Ray Bursts

Journal of Experimental and Theoretical Physics - Expansion of relativistic outflows of gamma-ray bursts (GRB) into medium created by the winds or their progenitor stars is accompanied by...     

Neutrinoless Double-Beta Decay to Excited 0+ States Mediated by Light Majorana Neutrinos

The neutrinoless double-beta decay (0 decay) to the first excited 0⁺ collective final state is examined for A = 76, 82, 100 and 136 nuclei by assuming light Majorana neutrino exchange mechanism. Realistic calculations of nuclear matrix elements are performed within the renormalized Quasiparticle Random Phase Approximation. Transitions to the first excited two-quadrupole phonon 0⁺ state are described within a boson expansion formalism. It is found that the ¹⁰⁰Mo is a good candidate for experimental study of the 0 decay to excited 0⁺ state due to small suppression of this transition relative to the transition to the ground state.     

Neutrino oscillation beyond the Standard Model

A short review of the theory of neutrino oscillation for non-standard neutrino interaction (NSI) which may exist at low energy is presented. Depending on the NSI, initial neutrino states can be mixed and final oscillation rates not necessarily factorize.     

Gaussian modification of neutrino energy loss on strongly screening nuclides 55Co and 56Ni by electron capture in stellar interior

Gaussian modifications of the neutrino energy loss (NEL) by electron capture on the strongly screening nuclides 55Co and 56Ni are investigated. The results show that in strong electron screening (SES),the NEL rates decrease without modifying the Gamow-Teller (G-T) resonance transition. For instance, the NEL rates of 55Co and 56Ni decrease more than two and three orders of magnitude for ρ7 = 5.86, T9≤ 5,Ye = 0.47, △ = 6.3, respectively. In contrast, due to Gaussian modification, the NEL rates increase about two orders of magnitude in SES. Due to SES, the maximum values of the C-factor (in %) on NEL of 55Co, 56Ni are of the order of 99.80%, 99.56% at ρ7 = 5.86 Ye = 0.47 and 99.60%, 99.65% at ρ7 = 106 Ye = 0.43, respectively.     

Quantum Decoherence of Neutrino Oscillation and Weak Measurement about Its Group Velocity

We theoretically explore the possibility of observing the quantum decoherence of neutrino oscillation due to the vacuum dispersion, that the wave-packet of neutrino spatially splits according to the different velocities of two mass eigenstates. We find that if this decoherence could be observed and the range of values of the mixing angle is known, then the superluminal neutrino phenomena could occur for some mixing angles as the consequence of a weak measurement about flavor mixing in the neutrino propagation. Our calculation gives the explicit dependence of group velocity shift to the decoherence factor and the weak value of neutrino's pre and post-selected states. We also study the related problems for the neutrino oscillation with three generations.     

Neutrino energy loss by electron capture on strongly screened iron group nuclei

The influences on the neutrino energy loss rates in iron group nuclei at the same density are investigated in the presence of strong electron screening and in the absence of electron screening. The results show that at a temperature of $15\ti10^9$\,K, the neutrino energy loss rates which come from the electron capture process for most iron group nuclei decrease no more than 2 orders of magnitude but for the others (such as $^{53,55,56,57,58,59,60}$Co, $^{56,59}$Ni) they can decrease about 3 orders of magnitude due to strong electron screening (SES), whereas, at a temperature of $10^9K$ the neutrino energy loss rates of the most iron group nuclei can be diminished greatly due to the SES. For example, $^{61}$Fe, $^{60}$Fe, and $^{62}$Ni the neutrino energy loss rates decrease about 4, 15 and 16 orders of magnitude and for $^{57}$Cr, $^{58}$Cr, and $^{60}$Cr decrease about 18, 12, and 10 orders of magnitude respectively. According to our calculations the neutrino energy loss rates of nuclei $^{58}$Mn, $^{59}$Mn, $^{60}$Mn, and $^{62}$Mn may decrease about 13 orders of magnitude at a temperature of $10^9$\,K due to the SES.     

Gaussian modification of neutrino energy loss on strongly screening nuclides ~（55）Co and ~（56）Ni by electron capture in stellar interior

Gaussian modifications of the neutrino energy loss (NEL) by electron capture on the strongly screening nuclides ⁵⁵Co and ⁵⁶Ni are investigated. The results show that in strong electron screening (SES), the NEL rates decrease without modifying the Gamow-Teller (G-T) resonance transition. For instance, the NEL rates of ⁵⁵Co and ⁵⁶Ni decrease more than two and three orders of magnitude for ρ₇=5.86, T₉≤5, Y_e=0.47, Δ=6.3, respectively. In contrast, due to Gaussian modification, the NEL rates increase about two orders of magnitude in SES. Due to SES, the maximum values of the C-factor (in %) on NEL of ⁵⁵Co, ⁵⁶Ni are of the order of 99.80%, 99.56% at ρ₇=5.86 Y_e=0.47 and 99.60%, 99.65% at ρ₇=106 Y_e=0.43, respectively.     

后中微子振荡发现的实验进展与展望

2015年诺贝尔物理学奖授予了发现中微子振荡也就是中微子有质量的实验。这个发现是至今为止,粒子物理标准模型——这一得到广泛实验验证的理论中唯一指明存在新物理的明显证据。文章将介绍中微子振荡发现以后主要的中微子实验物理目标、采用的探测技术、实验状况及其未来展望。