Search results for "Speed"

Absolute neutrino mass scale from flavor symmetries

2013

Abstract The 2012 has been an important year for neutrino physics, current data are reviewed and compared with 2011 global fit. Models based on discrete flavor symmetries predict neutrino mass mass sum-rule (MSR), which is useful to reduce the number of independent model parameters. We found that only four classes of MSR are possible. Such neutrino MSRs constrain the absolute neutrino mass scale. We study the implications of these mass relations for the lightest neutrino mass and for the lower bound of the effective mass m e e of the neutrinoless double beta decay.

Pulsar Velocities without Neutrino Mass

1998

We show that pulsar velocities may arise from anisotropic neutrino emission induced by resonant conversions of massless neutrinos in the presence of a strong magnetic field. The main ingredient is a small violation of weak universality and neither neutrino masses nor magnetic moments are required.

A large magnetic detector for the neutrino factory

2000

Abstract The physics opportunities of the neutrino factory have been the subject of a number of recent studies. It was shown that sensitive measurements of the angle θ 13 , of MSW effects, and of the sign of the atmospheric mass difference Δ m 23 2 are possible, and even CP violation in the neutrino mixing matrix may be within reach. The focus of interest is the oscillation ν e →ν μ , which leads in the well-defined neutrino beam of the neutrino factory to ‘wrong-sign’ muon events. In this paper, we show that a large magnetic detector will be capable of detecting with high efficiency and small backgrounds such wrong-sign muon events. We present a conceptual design of the apparatus and its p…

Neutrino mixing and future accelerator neutrino experiments

1992

Relic Neutrino Decoupling Including Flavour Oscillations

2005

In the early universe, neutrinos are slightly coupled when electron-positron pairs annihilate transferring their entropy to photons. This process originates non-thermal distortions on the neutrino spectra which depend on neutrino flavour, larger for nu_e than for nu_mu or nu_tau. We study the effect of three-neutrino flavour oscillations on the process of neutrino decoupling by solving the momentum-dependent kinetic equations for the neutrino spectra. We find that oscillations do not essentially modify the total change in the neutrino energy density, giving N_eff=3.046 in terms of the effective number of neutrinos, while the small effect over the production of primordial 4He is increased by…

Solar neutrinos as probes of neutrino–matter interactions

2004

Data from solar neutrino and KamLAND experiments have led to a discovery of nonzero neutrino masses. Here we investigate what these data can tell us about neutrino interactions with matter, including the poorly constrained flavor-changing nu_e-nu_tau interactions. We give examples of the interaction parameters that are excluded by the solar/KamLAND data and are beyond the reach of other experiments. We also demonstrate that flavor-changing interactions, at the allowed level, may profoundly modify the conversion probability for neutrinos of energy <~ 6 MeV and the values of the mass parameter inferred from the data. The implications for future experiments are discussed.

Working group on neutrino physics and astrophysics — concluding remarks I

1998

Abstract This part of the concluding remarks on the contributions and discussions in the working group on Neutrino Physics and Astrophysics summarises the following items: 1. 1) Neutrino mass measurement from Tritium beta decay, 2. 2) Neutrinoless double beta decay, 3. 3) Application of cryodetectors to the determination of neutrino properties, 4. 4) Search for a magnetic moment of the neutrino and, 5. 5) Limits on the mass of the Tau neutrino

Fitting Simpson's neutrino into the standard model

1985

Abstract I show how to accomodate the 17 keV state recently reported by Simpson as one of the neutrinos of the standard model. Experimental constraints can only be satisfied if the μ and τ neutrino combine to a very good approximation to form a Dirac neutrino of 17 keV leaving a light ν e . Neutrino oscillations will provide the most stringent test of the model. The cosmological bounds are also satisfied in a natural way in models with Goldstone bosons. Explicit examples are given in the framework of majoron-type models. Constraints on the lepton symmetry breaking scale which follow from astrophysics, cosmology and laboratory experiments are discussed.

The KATRIN sensitivity to the neutrino mass and to right-handed currents in beta decay

2007

The aim of the KArlsruhe TRItium Neutrino experiment KATRIN is the determination of the absolute neutrino mass scale down to 0.2 eV, with essentially smaller model dependence than from cosmology and neutrinoless double beta decay. For this purpose, the integral electron energy spectrum is measured close to the endpoint of molecular tritium beta decay. The endpoint, together with the neutrino mass, should be fitted from the KATRIN data as a free parameter. The right-handed couplings change the electron energy spectrum close to the endpoint, therefore they have some effect also to the precise neutrino mass determination. The statistical calculations show that, using the endpoint as a free par…

Subleading effects in the 1-2 sector: Non-standard neutrino interactions

2005

We have reconsidered the status of the large mixing angle (LMA) oscillation (OSC) interpretation of the solar neutrino data in a more general framework where non-standard neutrino interactions (NSI) are present. Using the latest data from all solar neutrino experiments and KamLAND we have found the existence of three LMA solutions, instead of the unique solution which holds in the absence of NSI, LMA-I. In addition to LMA-I, there is another solution with smaller Δ m 2 (LMA-0), and a new “dark-side” solution (LMA-D) with sin 2 θ = 0.70 . We comment on the potential of KamLAND and future solar neutrino experiments using 7Be and 8B neutrinos to lift the degeneracy between the LMA-I, LMA-0 and…