共查询到20条相似文献,搜索用时 36 毫秒
1.
General expressions of the neutrino oscillation phase in the generally static space-time with spherical symmetry are given.
The effect of the gravitational field on the oscillation length is embodied in the gravitational red shift factor. We find
that a blue shift of the oscillation length takes place when the neutrino travels out of the gravitational field. Then, we
discuss the variation of the oscillation length influenced by the cosmological constant. In the de Sitter space-time, the
positive cosmological constant prolongs the oscillation length. And, in the anti-de Sitter space-time, the negative cosmological
constant shortens it as expected. 相似文献
2.
Neutrino masses and the dark energy equation of state: relaxing the cosmological neutrino mass bound
Hannestad S 《Physical review letters》2005,95(22):221301
At present, cosmology provides the nominally strongest constraint on the masses of standard model neutrinos. However, this constraint is extremely dependent on the nature of the dark energy component of the Universe. When the dark energy equation of state parameter is taken as a free (but constant) parameter, the neutrino mass bound is sigma m(v) < or = 1.48 eV (95% C.L.), compared with sigma m(v) < or = 0.65 eV (95% C.L.) in the standard model where the dark energy is in the form of a cosmological constant. This has important consequences for future experiments aimed at the direct measurement of neutrino masses. We also discuss prospects for future cosmological measurements of neutrino masses. 相似文献
3.
In this Letter we discuss light neutrino dipole moments, computed in the neutrino-mass extended Standard Model, as a possible source for neutrino condensates which may cause cosmological constant observed today. 相似文献
4.
Superfluid condensation of neutrinos of cosmological origin at a low enough temperature can provide simple and elegant solution to the problems of neutrino oscillations and the accelerated expansion of the universe. It would give rise to a late time cosmological constant of small magnitude and also generate tiny masses for the neutrinos as observed from their flavor oscillations. We show that carefully prepared beta decay experiments in the laboratory would carry signatures of such a condensation, and thus, it would be possible to either establish or rule out neutrino condensation of cosmological scale in laboratory experiments. 相似文献
5.
We study the mass neutrino interference phase in Schwarzschild-de Sitter space time along the null trajectory and the geodesic line and obtain the effects of cosmological constant A on the neutrino oscillation. Firstly, in the high energy limit, we find that the phase along the geodesic keeps the double of that along the null. Secondly, we calculate the phase on the condition that the cosmological constant, A, is a small quantity. The correction of the phase due to A is given. Finally, we calculate the proper oscillation length in Schwarzschild-de Sitter space-time, which increases because of the existence of A, compared with the result in Schwarzschild space-time. All of our results can be reduced to those in Schwarzschild space-time as A approaches to zero. 相似文献
6.
Alan Chodos 《Foundations of Physics》2000,30(4):567-576
There are (at least) four numbers of physical and cosmological significance, whose inferred values, when expressed in mass units, cluster in a window below 1 eV. There are: the neutrino mass, the neutrino chemical potential, the cosmological constant, and the size of two extra dimensions (if the fundamental scale of gravity is 1–10 TeV). In this note, we imagine ways in which these four numbers could all be connected. 相似文献
7.
Lu Feng Jing-Fei Zhang Xin Zhang 《The European Physical Journal C - Particles and Fields》2017,77(6):418
We report the result of a search for sterile neutrinos with the latest cosmological observations. Both cases of massless and massive sterile neutrinos are considered in the \(\Lambda \)CDM cosmology. The cosmological observations used in this work include the Planck 2015 temperature and polarization data, the baryon acoustic oscillation data, the Hubble constant direct measurement data, the Planck Sunyaev–Zeldovich cluster counts data, the Planck lensing data, and the cosmic shear data. We find that the current observational data give a hint of the existence of massless sterile neutrino (as dark radiation) at the 1.44\(\sigma \) level, and the consideration of an extra massless sterile neutrino can indeed relieve the tension between observations and improve the cosmological fit. For the case of massive sterile neutrino, the observations give a rather tight upper limit on the mass, which implies that actually a massless sterile neutrino is more favored. Our result is consistent with the recent result of neutrino oscillation experiment done by the Daya Bay and MINOS collaborations, as well as the recent result of cosmic ray experiment done by the IceCube collaboration. 相似文献
8.
Zdeněk Stuchlík Jan Hladík Martin Urbanec Gabriel Török 《General Relativity and Gravitation》2012,44(6):1393-1417
Extremely compact stars (ECS) (having radius R < 3GM/c 2) contain captured null geodesics. Certain part of neutrinos produced in their interior will be trapped, influencing thus their neutrino luminosity and thermal evolution. The trapping effect has been previously investigated for the internal Schwarzschild spacetimes with the uniform distribution of energy density. Here, we extend our earlier study considering the influence of the cosmological constant Λ on the trapping phenomena. Our model for the interior of ECS is based on the internal Schwarzschild-(anti-)de Sitter (S(a)dS) spacetimes with uniform distribution of energy density matched to the external vacuum S(a)dS spacetime with the same cosmological constant. Assuming uniform and isotropic distribution of local neutrino emissivity we determine behavior of the trapping coefficients, i.e., “global” one representing influence on the neutrino luminosity and “local” one representing influence on the cooling process. We demonstrate that the repulsive (attractive) cosmological constant has tendency to enhance (damp) the trapping phenomena. 相似文献
9.
John D. Barrow 《Physics letters. [Part B]》1981,107(5):358-360
We recalculate the cosmological limits on hypothetical and undetected elementary particle masses under the assumption that the cosmological constant, Λ, is non-zero. The existing range of allowed masses is considerably extended by removing the unverified assumption that Λ=0. In particular, light neutrino masses up to ≈280 eV are compatible with cosmological observations. The implications of a cold early universe for these estimates are also outlined. 相似文献
10.
The present experimental results on neutrino flavour oscillations provide evidence for non-zero neutrino masses, but give no hint on their absolute mass scale, which is the target of beta decay and neutrinoless double-beta decay experiments. Crucial complementary information on neutrino masses can be obtained from the analysis of data on cosmological observables, such as the anisotropies of the cosmic microwave background or the distribution of large-scale structure. In this review we describe in detail how free-streaming massive neutrinos affect the evolution of cosmological perturbations. We summarize the current bounds on the sum of neutrino masses that can be derived from various combinations of cosmological data, including the most recent analysis by the WMAP team. We also discuss how future cosmological experiments are expected to be sensitive to neutrino masses well into the sub-eV range. 相似文献
11.
Steen Hannestad 《Progress in Particle and Nuclear Physics》2010,65(2):185-208
Cosmology provides an excellent laboratory for testing various aspects of neutrino physics. Here, I review the current status of cosmological searches for neutrino mass, as well as other properties of neutrinos. Future cosmological probes of neutrino properties are also discussed in detail. 相似文献
12.
Sergio Pastor 《Physics of Particles and Nuclei》2011,42(4):628-640
Neutrinos can play an important role in the evolution of the Universe, modifying some of the cosmological observables. We
describe how the precision of present cosmological data can be used to learn about neutrino properties, in particular their
mass. We show how the analysis of current cosmological observations provides an upper bound on the sum of neutrino masses,
with improved sensitivity from future cosmological measurements. 相似文献
13.
We consider some cosmological consequences of a relic neutrino asymmetry. A relic neutrino degeneracy enhances the contribution of massive neutrinos to the present energy density of the Universe, and modifies the power spectrum of radiation and matter. We also show that even the smallest neutrino mass consistent with the Super—Kamiokande data is relevant for cosmological models, provided that a relic neutrino asymmetry exists. 相似文献
14.
A. D. Dolgov 《Physics of Atomic Nuclei》2008,71(12):2152-2164
A brief review for particle physicists on the cosmological impact of neutrinos and on restrictions on neutrino properties
from cosmology is given. The paper includes a discussion of upper bounds on neutrino mass and possible ways to relax them,
methods to observe the cosmic-neutrino background, bounds on the cosmological lepton asymmetry which are strongly improved
by neutrino oscillations, cosmological effects of breaking of the spin-statistics theorem for neutrinos, bounds on mixing
parameters of active and possible sterile neutrinos with account of active-neutrino oscillations, bounds on right-handed currents
and neutrino magnetic moments, and some more.
The text was submitted by the authors in English. 相似文献
15.
Elgarøy Ø Lahav O Percival WJ Peacock JA Madgwick DS Bridle SL Baugh CM Baldry IK Bland-Hawthorn J Bridges T Cannon R Cole S Colless M Collins C Couch W Dalton G De Propris R Driver SP Efstathiou GP Ellis RS Frenk CS Glazebrook K Jackson C Lewis I Lumsden S Maddox S Norberg P Peterson BA Sutherland W Taylor K 《Physical review letters》2002,89(6):061301
We constrain f(nu) identical with Omega(nu)/Omega(m), the fractional contribution of neutrinos to the total mass density in the Universe, by comparing the power spectrum of fluctuations derived from the 2 Degree Field Galaxy Redshift Survey with power spectra for models with four components: baryons, cold dark matter, massive neutrinos, and a cosmological constant. Adding constraints from independent cosmological probes we find f(nu)<0.13 (at 95% confidence) for a prior of 0.1相似文献
16.
Daniela P. Kirilova 《Central European Journal of Physics》2004,2(3):467-491
The observational and theoretical status of neutrino oscillations in connection with solar and atmospheric neutrino anomalies
is presented briefly. The effect of neutrino oscillations on the evolution of the early Universe is discussed in detail. A
short review is given of the standard Big Bang Nucleosynthesis (BBN) and the influence of resonant and non-resonant neutrino
oscillations on active neutrinos and on primordial synthesis of He-4. BBN cosmological constraints on neutrino oscillation
parameters are discussed. 相似文献
17.
Within the minimal supersymmetric extension of the Standard Model, the one-photon decay of the neutrino is studied on the basis of astrophysical, cosmological, and experimental data. Limits on the neutrino masses are obtained. 相似文献
18.
Y.-L. Wu 《The European Physical Journal C - Particles and Fields》1999,10(3):491-497
A realistic scheme for masses and mixing of leptons is investigated in the model with gauged SO(3) lepton flavor symmetry.
Within this scheme, a nearly bimaximal neutrino mixing pattern with a maximal CP-violating phase is found to be the only possible
solution for reconciling both solar and atmospheric neutrino flux anomalies. Three Majorana neutrino masses are nearly degenerate
and large enough to play a significant cosmological role. Lepton flavor-violating effects via SO(3) gauge interactions can
be as large as the present experimental limits. Masses of the SO(3) gauge bosons are bounded to be above 24 TeV when the SO(3)
gauge boson mixing angle and coupling constant are taken to be the same as those ( and g) in the electroweak theory.
Received: 10 February 1999 / Published online: 8 September 1999 相似文献
19.
In Reissner--Nordstr?m--de Sitter space--time, we calculate the interference phase of mass neutrino along geodesic in the radial direction, and then investigate the effects of the cosmological constant La on the phase. Morever, the expression of the interference phase can be reduced to that in Reissner--Nordstr?m space--time when Λ approaches to zero. 相似文献
20.
Raj Gandhi Subhendra Mohanty Tarun Souradeep S Agarwalla K Bhattacharya B Brahmachari R Crittenden S Goswami P Ghoshal M Lindner H S Mani S Mitra S Pascoli S Panda R Rangarajan S Ray T Roy Choudhury R Saha S Sarkar A Srivastava R Sheth S Uma Sankar U Yajnik 《Pramana》2006,67(4):735-742
The working group on astroparticle and neutrino physics at WHEPP-9 covered a wide range of topics. The main topics were neutrino
physics at INO, neutrino astronomy and recent constraints on dark energy coming from cosmological observations of large scale
structure and CMB anisotropy. 相似文献