123 research outputs found
Low Energy Neutrino Physics after SNO and KamLAND
In the recent years important discoveries in the field of low energy neutrino
physics (E in the MeV range) have been achieved. Results of the
solar neutrino experiment SNO show clearly flavor transitions from to
. In addition, the long standing solar neutrino problem is
basically solved. With KamLAND, an experiment measuring neutrinos emitted from
nuclear reactors at large distances, evidence for neutrino oscillations has
been found. The values for the oscillation parameters, amplitude and phase,
have been restricted. In this paper the potential of future projects in low
energy neutrino physics is discussed. This encompasses future solar and reactor
experiments as well as the direct search for neutrino masses. Finally the
potential of a large liquid scintillator detector in an underground laboratory
for supernova neutrino detection, solar neutrino detection, and the search for
proton decay is discussed.Comment: Invited brief review, World Scientific Publishing Compan
Photon-Neutrino Interactions
We discuss the interaction of photons with neutrinos including two lepton
loops. The parity violation in the gamma-nu to gamma-nu channel due to two
lepton loops is substantially enhanced relative to the one lepton loop
contribution. However there is no corresponding enhancement in the parity
conserving amplitude in either the direct or the cross channel.Comment: 12 pages, 5 figure
Neutrino Experiments: Status, Recent Progress, and Prospects
Neutrino physics has seen an explosion of activity and new results in the
last decade. In this report the current state of the field is summarized, with
a particular focus on progress in the last two years. Prospects for the near
term (roughly 5 years) are also described.Comment: 14 pages, 10 figures, proceedings of plenary talk at EPS HEP 2007
Conference, Manchester, UK. Updated with citation added to Figure 1
Finding Evidence for Massive Neutrinos using 3D Weak Lensing
In this paper we investigate the potential of 3D cosmic shear to constrain
massive neutrino parameters. We find that if the total mass is substantial
(near the upper limits from LSS, but setting aside the Ly alpha limit for now),
then 3D cosmic shear + Planck is very sensitive to neutrino mass and one may
expect that a next generation photometric redshift survey could constrain the
number of neutrinos N_nu and the sum of their masses m_nu to an accuracy of
dN_nu ~ 0.08 and dm_nu ~ 0.03 eV respectively. If in fact the masses are close
to zero, then the errors weaken to dN_nu ~ 0.10 and dm_nu~0.07 eV. In either
case there is a factor 4 improvement over Planck alone. We use a Bayesian
evidence method to predict joint expected evidence for N_nu and m_nu. We find
that 3D cosmic shear combined with a Planck prior could provide `substantial'
evidence for massive neutrinos and be able to distinguish `decisively' between
many competing massive neutrino models. This technique should `decisively'
distinguish between models in which there are no massive neutrinos and models
in which there are massive neutrinos with |N_nu-3| > 0.35 and m_nu > 0.25 eV.
We introduce the notion of marginalised and conditional evidence when
considering evidence for individual parameter values within a multi-parameter
model.Comment: 9 pages, 2 Figures, 2 Tables, submitted to Physical Review
Neutrinos in a spherical box
In the present paper we study some neutrino properties as they may appear in
the low energy neutrinos emitted in triton decay with maximum neutrino energy
of 18.6 keV. The technical challenges to this end can be achieved by building a
very large TPC capable of detecting low energy recoils, down to a a few tenths
of a keV, within the required low background constraints. More specifically We
propose the development of a spherical gaseous TPC of about 10-m in radius and
a 200 Mcurie triton source in the center of curvature. One can list a number of
exciting studies, concerning fundamental physics issues, that could be made
using a large volume TPC and low energy antineutrinos: 1) The oscillation
length involving the small angle of the neutrino mixing matrix, directly
measured in this disappearance experiment, is fully contained inside the
detector. Measuring the counting rate of neutrino-electron elastic scattering
as a function of the distance of the source will give a precise and unambiguous
measurement of the oscillation parameters free of systematic errors. In fact
first estimates show that even with a year's data taking a sensitivity of a few
percent for the measurement of the above angle will be achieved. 2) The low
energy detection threshold offers a unique sensitivity for the neutrino
magnetic moment which is about two orders of magnitude beyond the current
experimental limit. 3) Scattering at such low neutrino energies has never been
studied and any departure from the expected behavior may be an indication of
new physics beyond the standard model. In this work we mainly focus on the
various theoretical issues involved including a precise determination of the
Weinberg angle at very low momentum transfer.Comment: 16 Pages, LaTex, 7 figures, talk given at NANP 2003, Dubna, Russia,
June 23, 200
Neutrino mass limits from SDSS, 2dFGRS and WMAP
We investigate whether cosmological data suggest the need for massive
neutrinos. We employ galaxy power spectrum measurements from the Sloan Digital
Sky Survey (SDSS) and the Two Degree Field Galaxy Redshift Survey (2dFGRS),
along with cosmic microwave background (CMB) data from the Wilkinson Microwave
Anisotropy Probe (WMAP) and 27 other CMB experiments. We also use the
measurement of the Hubble parameter from the Hubble Space Telescope (HST) Key
Project. We find the sum of the neutrino masses to be smaller than 0.75 eV at
2\sigma (1.1 eV at 3\sigma).Comment: 4 pages, 2 figures. Only unconstrained bias fit included. References
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Tests of CPT Invariance at Neutrino Factories
We investigate possible tests of CPT invariance on the level of event rates
at neutrino factories. We do not assume any specific model but phenomenological
differences in the neutrino-antineutrino masses and mixing angles in a Lorentz
invariance preserving context, such as it could be induced by physics beyond
the Standard Model. We especially focus on the muon neutrino and antineutrino
disappearance channels in order to obtain constraints on the
neutrino-antineutrino mass and mixing angle differences; we found, for example,
that the sensitivity
could be achieved.Comment: 6 pages, 1 figure, RevTeX4. Final version to be published in Phys.
Rev.
Technique for Direct eV-Scale Measurements of the Mu and Tau Neutrino Masses Using Supernova Neutrinos
Early black hole formation in a core-collapse supernova will abruptly
truncate the neutrino fluxes. The sharp cutoff can be used to make
model-independent time-of-flight neutrino mass tests. Assuming a neutrino
luminosity of erg/s per flavor at cutoff and a distance of 10 kpc,
SuperKamiokande can detect an electron neutrino mass as small as 1.8 eV, and
the proposed OMNIS detector can detect mu and tau neutrino masses as small as 6
eV. This {\it Letter} presents the first technique with direct sensitivity to
eV-scale mu and tau neutrino masses.Comment: 4 pages including 3 inline figures. Submitted to Physical Review
Letter
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