9 research outputs found
Status of three-neutrino oscillations after the SNO-salt data
We perform a global analysis of neutrino oscillation data in the framework of
three neutrinos, including the recent improved measurement of the neutral
current events at SNO. In addition to all current solar neutrino data we take
into account the reactor neutrino data from KamLAND and CHOOZ, the atmospheric
neutrino data from Super-Kamiokande and MACRO, as well as the first spectral
data from the K2K long baseline accelerator experiment. The up-to-date best fit
values and allowed ranges of the three-flavour oscillation parameters are
determined from these data. Furthermore, we discuss in detail the status of the
small parameters alpha = Delta_m^2_Sol / Delta_m^2_Atm and sin^2(theta_13),
which fix the possible strength of CP violating effects in neutrino
oscillations.Comment: 16 pages, LaTeX file using RevTEX4, 10 figures and 1 table included.
The conclusions reached in version 1 regarding the restriction on
sin^2(theta_13) are now corrected, the solar bound is weaker than that from
reactors even after the inclusion of the SNO salt data. In addition the full
data set has now been reanalized using the pull method instead of the
standard chi-square approach. A few references have also been adde
Probing Low Energy Neutrino Backgrounds with Neutrino Capture on Beta Decaying Nuclei
We study the interaction of low energy neutrinos on nuclei that spontaneously
undergo beta decay showing that the product of the cross section times neutrino
velocity takes values as high as 10^{-42} cm^2 c for some specific nuclei that
decay via allowed transitions. The absence of energy threshold and the value of
the cross section single out these processes as a promising though very
demanding approach for future experiments aimed at a direct detection of low
energy neutrino backgrounds such as the cosmological relic neutrinos.Comment: Includes a discussion of local relic neutrino density effect on
neutrino capture rate. Accepted for publication in JCA
Supersymmetric Origin of Neutrino Mass
Supersymmetry with breaking of R-parity provides an attractive way to
generate neutrino masses and lepton mixing angles in accordance to present
neutrino data. We review the main theoretical features of the bilinear R-parity
breaking (BRpV) model, and stress that it is the simplest extension of the
minimal supersymmetric standard model (MSSM) which includes lepton number
violation. We describe how it leads to a successful phenomenological model with
hierarchical neutrino masses. In contrast to seesaw models, the BRpV model can
be probed at future collider experiments, like the Large Hadron Collider or the
Next Linear Collider, since the decay pattern of the lightest supersymmetric
particle provides a direct connection with the lepton mixing angles determined
by neutrino experiments.Comment: 21 pages, 8 figures, review for NJP focus issue on neutrino
Structure formation with strongly interacting neutrinos - implications for the cosmological neutrino mass bound
We investigate a model where neutrinos are strongly coupled to a new, light
scalar field. In this model neutrinos annihilate as soon as they become
non-relativistic in the early universe, and a non-zero neutrino mass has a
marginal effect on the matter power spectrum. However, the angular power
spectrum of the cosmic microwave background (CMB) is changed significantly
because the strongly interacting fluid of neutrinos and scalars does not
experience any anisotropic stress. Such models are strongly disfavoured by
current observations. Interestingly, this leads to the conclusion that the
relativistic energy density around the epoch of recombination must be in the
form of very weakly interacting particles. This conclusion is independent of
the specific interaction model.Comment: 15 pages, 9 figures, minor changes, matches JCAP versio
Models of Neutrino Masses and Mixings
We review theoretical ideas, problems and implications of neutrino masses and
mixing angles. We give a general discussion of schemes with three light
neutrinos. Several specific examples are analyzed in some detail, particularly
those that can be embedded into grand unified theories.Comment: 44 pages, 2 figures, version accepted for publication on the Focus
Issue on 'Neutrino Physics' edited by F.Halzen, M.Lindner and A. Suzuki, to
be published in New Journal of Physics
Physics at a future Neutrino Factory and super-beam facility
The conclusions of the Physics Working Group of the international scoping study of a future Neutrino Factory and super-beam facility (the ISS) are presented. The ISS was carried by the international community between NuFact05, (the 7th International Workshop on Neutrino Factories and Superbeams, Laboratori Nazionali di Frascati, Rome, June 21-26, 2005) and NuFact06 (Ivine, California, 24{30 August 2006). The physics case for an extensive experimental programme to understand the properties of the neutrino is presented and the role of high-precision measurements of neutrino oscillations within this programme is discussed in detail. The performance of second generation super-beam experiments, beta-beam facilities, and the Neutrino Factory are evaluated and a quantitative comparison of the discovery potential of the three classes of facility is presented. High-precision studies of the properties of the muon are complementary to the study of neutrino oscillations. The Neutrino Factory has the potential to provide extremely intense muon beams and the physics potential of such beams is discussed in the final section of the report.The conclusions of the Physics Working Group of the international scoping study of a future Neutrino Factory and super-beam facility (the ISS) are presented. The ISS was carried by the international community between NuFact05, (the 7th International Workshop on Neutrino Factories and Superbeams, Laboratori Nazionali di Frascati, Rome, June 21-26, 2005) and NuFact06 (Ivine, California, 24{30 August 2006). The physics case for an extensive experimental programme to understand the properties of the neutrino is presented and the role of high-precision measurements of neutrino oscillations within this programme is discussed in detail. The performance of second generation super-beam experiments, beta-beam facilities, and the Neutrino Factory are evaluated and a quantitative comparison of the discovery potential of the three classes of facility is presented. High-precision studies of the properties of the muon are complementary to the study of neutrino oscillations. The Neutrino Factory has the potential to provide extremely intense muon beams and the physics potential of such beams is discussed in the final section of the report