ON THE NEUTRINO HALO OF GALAXIES OR GALAXIES CLUSTER AND ITS RESTRICTION ON NEUTRINO MASS

We present a simple and crude model of galaxies consisting of baryons and neutrinos with spherical symmetry. The baryon matter is rotatinq. in the central region of the galaxy as a nucleus. If the rotational curve of the heavy matter is known from the observational data, then the gravitational potential, and therefore the density distribution in this region, can also be obtained. This enables us to estimate the mass and the radius of the neutrino halo. Furthermore, the condition on the interface of the nucleus-halo will set an upper bound on neutrino mass. If the corresponding parameters duoted in Ref.[10] are adopted, then a value of ≤20eV. for the neutrino mass is obtained. By choosing m_v=15eV and a parameter in the rotational curve n=4, one can deduce that neutrino halo radius is about four times the heavy matter radius, and the total mass of neutrinos is about 14 times that of baryons. It seems, that these results are not in contradiction with the observations on the missing mass of the galaxies^[6].     

A MODEL OF NEUTRINO STELLAR SYSTEM AND THE UPPER BOUND OF NEUTRINO MASS OBTAINED FROM THE RCTATION CURVES OF SOME GALAXIES

We discuss in this paper a stellar model of degenerate massive neutrinos with a core made of heavy matter. Dimension of the core is much smaller than the scale of neutrino star. The Oppenheimer-Volkoff equation is solved for such a system. Our calculation shows that under certain conditions, this neutrino halo will resemble a pure neutrino star. We have further obtained insides the neutrino star (or halo) the rdtation curve and the gravitational red shifts. It is interesting to note that the relative rotation velocity v(r)EV(r)/V(R) (R is the radius of the neutrino star) depends only on the relative coordinate ξ=r/R in the nonrelativistic cases. Therefore, all nonrelativistically degenerate neutrino systems will have a universa1 relative rotation curve(v versus ξ). Within the accuracy of numeri calcalculation, we have also obtained a useful relation connecting the maximum velocity V_m and the corresponding coordinate R_m as V_mR_m2=0.231. By comparing this relation with the observed rotation data at large distances for some galaxies, we have obtained an upper bound for neutrino mass of about 6-9eV.     

Can symmetric texture reproduce neutrino bi-large mixing?

We study the symmetric texture of geometric form with 2-zeros to see if it is consistent with the presently-known neutrino masses and mixings. In the neutrino mass matrix elements we obtain numerically the allowed region of the parameters including CP-violating phases, which can reproduce the present neutrino experiment data. The result of this analysis dictates the narrow region for the GUT model including Pati–Salam symmetry with texture zeros to be consistent with the experimental data. The |U_e3| and J_CP are also predicted in such models.     

ON THE NEUTRINO MASS,THE ABUNDANCE OF RIGHT-HANDED NEUTRINO AND THE CLOSENESS OF THE UNIVERSE

We point out that although the neutrino mass is finite,the left-handed neutrino density still dominates over the righthanded one in the universe unless there exists one or more elementary fernions (quark or lepton) whose mass is larger than 10⁶ GeV. or M_WR/M_WL≤10². (M_WLand M_WR are the left and right handed intermediate boson respectively.If there exists neutrino the mass of which is about 34 ev. as indicated in some experiments, then one can conclude that the total neutrino mass of the universe s,bvld contribute abput 99%. to the whole masses and lead to the closeness of the universe.This conclusion can be brought to the agreement of all observation datd which have been-obtained so far. A mass limit of all species of neutrinos obtained by reexamining all data is ≤ 200 eV.     

三维QED中的几个重要问题（英文）

三维量子电动力学是一种看上去比较简单的Abel 类型的非微扰系统,其本身却有很多需要澄清的基本问题。从该系统是否具有密度依赖性,有限温下是否具有动力学自发对称破却以及规范玻色子可否具有质量这三方面出发,阐述了对三维量子电动力学一些基本问题的看法。Quantum electrodynamics in (2+1) dimensions (QED₃) is an important nonperturbative system. This seems relatively simple Abel system, there are several issues that need to be clarified: whether or not the partition function of the system depends on chemical potential; whether or not there exists dynamical chiral symmetric breaking; whether or not the boson can acquires nonzero mass. In this paper, we give an in sight of the traits of QED₃ from the dependence of density, temperature and massive boson to discuss those problems.     

地基光度测量方式对比

介绍了地基测量空间目标光度的两种方式。首先介绍了系统组成及对比测量原理,然后基于工程角度分析提出了宽谱段测量和滤光片测量两种方式,并给出了两种测量方式的误差分析。若G型恒星及空间目标在同一视场可选择宽谱段测量方式,若途经天区G型定标星较少,可以选择滤光片测量方式。外场实验验证表明,宽谱段测量方式信噪比较高,可探测的极限星等为16等星,在天气条件较好的情况下测量精度在0.15星等左右,而滤光片测量方式由于探测到的能量较少,在相同信噪比下可探测极限星等为14等星,天气变化较小条件下测量精度在0.02星等左右,两种测量方式误差相当,但宽谱段测量方式定标恒星数量增加2.4倍,便于数据处理与计算。     

Neutrino astronomy and massive long-lived particles from the big bang

We consider the neutrino flux from the decay of long-lived big-bang particles. The red-shift z_tr at which the neutrino transparency of the universe sets in is calculated as a function of neutrino energy: z_tr 1 × 10⁵ for TeV neutrinos and z_tr 3 × 10⁶ for 10 MeV neutrinos. One might expect the production of detectable neutrino flux at z z_tr, but, as demonstrated in this paper, the various upper limits, most notably due to nucleosynthesis and diffuse X- and gamma-rays, preclude this possibility. Unless the particle decay is strongly dominated by the pure neutrino channel, observable neutrino flux can be produced only at the current epoch, corresponding to red-shift z ≈ 0. For the thermal relics which annihilate through the gauge bosons of SU(3)×SU(2)×U(1) group, the neutrino flux can be marginally detectable at 0.1 < E_v < 10 TeV. As an example of non-thermal relics we consider gravitinos. If gravitinos are the lightest supersymmetric particles (LSP) they can produce the detectable neutrino flux in the form of a neutrino line with energy , where M_G is the gravitino mass. The flux strongly depends on the mechanisms of R-parity violation. It is shown that heavy gravitinos (M_G 100 GeV) can make up the dark matter in the universe.     

The Two-Nucleon Mechanism for the Neutrinoless Double Beta Decay and the BCS Nuclear Wave Function

A method of using the Bardeen-Cooper-Schrieffer (BCS) nuclear wave function to treat the two-nucleon mechanism for neutiinoless double beta decay process 0⁺ → 0⁺ is proposed.The neutrinoless decay mode and the neutrinoless decay accompanied by a Majoron emission mode of ⁸²Se are studikd. Our cdculated results show that to reproduce the experimental value of γ^(ov) > 1.8 × 10²² yr for neutrinoless double beta decai of ⁸²Se the Majorana neutrino mass m_v < 6.2 eV and the mixing parameter of right-handed current η < 7.0 × 10^-6 In the emission with a Majoron mode the effective Majoron coupling to neutrino is deduced from the experimental value of γ^(ov,H) > 4.4 × 10²⁰ yr for ⁸²Se with the result H0> < 6.2 × 10^-4.     

Limits of neutrino stability from the γ-ray flux measured in coincidence with neutrinos from SN 1987a

Limits for the neutrino decay ν_H→ν_L+γ, where ν_H and ν_L are assumed to be massive neutrinos withm_VH>m_VL, are presented using data from the Solar Maximum Mission satellite taken in coincidence with the detected neutrino burst from SN 1987A. These limits are essentially independent of supernova models and are and τ/m_νμ,τ>3.3×10¹⁴ s/eV for a thermal spectrum at a temperature .     

中微子质量和中微子振荡实验

本介绍中微子质量测量的历史和现状。介绍太阳中微子丢失实验的结果和大气μ中微子丢失实验结果。这些结果表明存在中微子振荡,即中微子具有质量。它是超出标准模型的信号。本还介绍了21世纪初研究中微子振荡的若干重要实验,例如长基线中微子振荡实验以及建造μ子 贮存环来产生高能电子中微子束进行中微子振荡的实验以及测量中微子振荡时的CP破坏的设想。     

中微子的质量

本文讨论了μ中微子的静质量在各种过程中的效应,特别分析了两个此效应表现得明显的过程,μ介子与电子的湮没和π辐射衰变。指出给μ中微子以一个不太小的静质量,例如5m_e能和目前已有的一切实验不矛盾,并指出进一步确定μ中微子的质量的可能的实验。     

THE n-p MASS RATIO IN QCD SUM RULES

The QCD sum rules for the proton. mass,the n-p mass ratio and the optimal observation point are analysed, which can greatly improve the precision of the theoretical results. If we take =

and m_u/(m_u+m_d)-=0.35 which agree with the values from SVZ and current algebra^[1,2],we obtain M_p=935.86MeV and M_p/M_n=0.99871 which coincide quite well with experimental values.The isospin behavior of light quarks is investigated. It shows that the isospin symmetry of the light quark condensates is very good up to the low-energy region (about 500MeV),and that the n-p mass difference can be originated from the u-and d-quark mass differences.     

Possible manifestations of the existence of a fourth-generation neutrino

A fourth generation of fermions predicted by the phenomenological heterotic string models can possess a new, strictly conserved charge. Among other things, this leads to the hypothesis of the existence of a fourth massive stable neutrino. A comparison of this hypothesis with the data obtained in the DAMA underground experiment to search for massive weakly-interacting cosmic particles with hidden mass and with the EGRET measurements of the >1 GeV galactic gamma-ray background gives a value m≈50 GeV for the possible mass of the fourth neutrino. It is shown that the hypothesis can be checked in accelerator experiments. The positron signal from annihilation of massive relic neutrinos in the galaxy is calculated. A search for this signal is is within the reach of planned cosmic-ray investigations. Pis’ma Zh. éksp. Teor. Fiz. 69, No. 6, 402–406 (25 March 1999)     

Weighing Neutrinos in f(R) Gravity in Light of BICEP2

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.     

NEUTRINO MAGNETIC MOMENT IN SUPERSTRING INSPIRED MODELS

In superstring E₆ models right-handed leptonic currents can arise from the mixing between the ordinary leptons and tha exotic leptons. Contributions to the neutrino magnetic moment due to this new interaction are examined. Although the result appears to be directly proportional to the heavy exotic charged lepton mass, it is shown, however, that the mixing is proportional to the ratio of the neutrino mass and the exotic lepton mass. The combination of these two factors yields a result which is of the order of that given by the SU(2)_LxU(1)_Y model.     

Minimal SUSY SO(10), b–τ unification and large neutrino mixings

We show that the assumption of type II seesaw mechanism for small neutrino masses coupled with b–τ mass unification in a minimal SUSY SO(10) model leads not only to a natural understanding of large atmospheric mixing angle (θ₂₃) among neutrinos, as recently noted, but also to large solar angle (θ₁₂) and a small θ₁₃≡U_e3 as required to fit observations. No additional symmetries are required to obtain large neutrino mixings. The proposed long baseline neutrino experiments will provide a crucial test of this model since it predicts U_e30.16.     

Decay and decoupling of heavy right-handed Majorana neutrinos in the L–R model

Heavy right-handed neutrinos are of current interest. The interactions and decay of such neutrinos determine their decoupling epoch during the evolution of the universe. This in turn affects various observable features like the energy density, nucleosynthesis, CMBR spectrum, galaxy formation and baryogenesis. Here, we consider reduction of right-handed electron-type Majorana neutrinos, in the left–right symmetric model, by the channel and the channel originating from an anomaly, involving the gauge group, as well as decay of such neutrinos. We study the reduction of these neutrinos for different ranges of left–right model parameters, and find that, if the neutrino mass exceeds the right-handed gauge boson mass, then the neutrinos never decouple for realistic values of the parameters, but, rather, decay in equilibrium. Because there is no out-of-equilibrium decay, no mass bounds can be set for the neutrinos. Received: 1 November 2000 / Published online: 23 February 2001     

Impact of massive neutrinos on the nonlinear matter power spectrum

We present the first attempt to analytically study the nonlinear matter power spectrum for a mixed dark matter model containing neutrinos of total mass ~0.1 eV, based on cosmological perturbation theory. The suppression in the power spectrum amplitudes due to massive neutrinos is enhanced in the weakly nonlinear regime. We demonstrate that, thanks to this enhanced effect, the use of such a nonlinear model may enable a precision of sigma(m(nu,tot)) ~ 0.07 eV in constraining the total neutrino mass for the planned galaxy redshift survey, a factor of 2 improvement compared to the linear regime.     

ON THE HYDROGEN MOLECULAR CORRECTION TO THE TRITON β-SPECTRUM AND THE MEASUREMENT OF THE NEUTRINO MASS

By using a highly accurate variational wave function with 50 parameters for hydrogen molecule^[4] and the wave function of HeH⁺ used by Wolniewicz with 64 parameters^[5], the behavior of the β-spectrum of H-T→ HeH⁺+β^-+νe is discussed. The spectral shape thus obtained deviates remarkably from the β-spectrum of an atomic triton, and hence is different from the for mula used by Lyubimov et al. in determining the neutrino mass. This means that the "atomic approximation" is invalid in describing the molecular β-spectrum of valine, and the conclusion about the value of neutrino mass based upon the analysis of β -spectrum of valine also cannot be regarded as a reliable one. Therefore, in order to obtain ari accurate value of neutrino mass from the β-spectral shape, it is important to investigate the structure of the radioactive source, from which the corection has arisen.