150 research outputs found
General bounds on non-standard neutrino interactions
We derive model-independent bounds on production and detection non-standard
neutrino interactions (NSI). We find that the constraints for NSI parameters
are around O(10^{-2}) to O(10^{-1}). Furthermore, we review and update the
constraints on matter NSI. We conclude that the bounds on production and
detection NSI are generally one order of magnitude stronger than their matter
counterparts.Comment: 18 pages, revtex4, 1 axodraw figure. Minor changes, matches published
versio
Optimized Two-Baseline Beta-Beam Experiment
We propose a realistic Beta-Beam experiment with four source ions and two
baselines for the best possible sensitivity to theta_{13}, CP violation and
mass hierarchy. Neutrinos from 18Ne and 6He with Lorentz boost gamma=350 are
detected in a 500 kton water Cerenkov detector at a distance L=650 km (first
oscillation peak) from the source. Neutrinos from 8B and 8Li are detected in a
50 kton magnetized iron detector at a distance L=7000 km (magic baseline) from
the source. Since the decay ring requires a tilt angle of 34.5 degrees to send
the beam to the magic baseline, the far end of the ring has a maximum depth of
d=2132 m for magnetic field strength of 8.3 T, if one demands that the fraction
of ions that decay along the straight sections of the racetrack geometry decay
ring (called livetime) is 0.3. We alleviate this problem by proposing to trade
reduction of the livetime of the decay ring with the increase in the boost
factor of the ions, such that the number of events at the detector remains
almost the same. This allows to substantially reduce the maximum depth of the
decay ring at the far end, without significantly compromising the sensitivity
of the experiment to the oscillation parameters. We take 8B and 8Li with
gamma=390 and 656 respectively, as these are the largest possible boost factors
possible with the envisaged upgrades of the SPS at CERN. This allows us to
reduce d of the decay ring by a factor of 1.7 for 8.3 T magnetic field.
Increase of magnetic field to 15 T would further reduce d to 738 m only. We
study the sensitivity reach of this two baseline two storage ring Beta-Beam
experiment, and compare it with the corresponding reach of the other proposed
facilities.Comment: 17 pages, 3 eps figures. Minor changes, matches version accepted in
JHE
, and the neutrino mass hierarchy at a double baseline Li/B -Beam
We consider a -Beam facility where Li and B ions are
accelerated at , accumulated in a 10 Km storage ring and let
decay, so as to produce intense and beams. These beams
illuminate two iron detectors located at Km and
Km, respectively. The physics potential of this setup is analysed in full
detail as a function of the flux. We find that, for the highest flux ( ion decays per year per baseline), the sensitivity to
reaches ; the sign of
the atmospheric mass difference can be identified, regardless of the true
hierarchy, for ; and, CP-violation
can be discovered in 70% of the -parameter space for , having some sensitivity to CP-violation down to
for .Comment: 35 pages, 20 figures. Minor changes, matches the published versio
Neutrino Probes of the Nature of Light Dark Matter
Dark matter particles gravitationally trapped inside the Sun may annihilate
into Standard Model particles, producing a flux of neutrinos. The prospects of
detecting these neutrinos in future multi-\kton{} neutrino detectors designed
for other physics searches are explored here. We study the capabilities of a
34/100 \kton{} liquid argon detector and a 100 \kton{} magnetized iron
calorimeter detector. These detectors are expected to determine the energy and
the direction of the incoming neutrino with unprecedented precision allowing
for tests of the dark matter nature at very low dark matter masses, in the
range of 5-50 GeV. By suppressing the atmospheric background with angular cuts,
these techniques would be sensitive to dark matter - nucleon spin dependent
cross sections at the fb level, reaching down to a few ab for the most
favorable annihilation channels and detector technology.Comment: Minor changes and clarifications, matches JCAP versio
Underground Neutrino Detectors for Particle and Astroparticle Science: the Giant Liquid Argon Charge Imaging ExpeRiment (GLACIER)
The current focus of the CERN program is the Large Hadron Collider (LHC),
however, CERN is engaged in long baseline neutrino physics with the CNGS
project and supports T2K as recognized CERN RE13, and for good reasons: a
number of observed phenomena in high-energy physics and cosmology lack their
resolution within the Standard Model of particle physics; these puzzles include
the origin of neutrino masses, CP-violation in the leptonic sector, and baryon
asymmetry of the Universe. They will only partially be addressed at LHC. A
positive measurement of would certainly give a
tremendous boost to neutrino physics by opening the possibility to study CP
violation in the lepton sector and the determination of the neutrino mass
hierarchy with upgraded conventional super-beams. These experiments (so called
``Phase II'') require, in addition to an upgraded beam power, next generation
very massive neutrino detectors with excellent energy resolution and high
detection efficiency in a wide neutrino energy range, to cover 1st and 2nd
oscillation maxima, and excellent particle identification and
background suppression. Two generations of large water Cherenkov
detectors at Kamioka (Kamiokande and Super-Kamiokande) have been extremely
successful. And there are good reasons to consider a third generation water
Cherenkov detector with an order of magnitude larger mass than Super-Kamiokande
for both non-accelerator (proton decay, supernovae, ...) and accelerator-based
physics. On the other hand, a very massive underground liquid Argon detector of
about 100 kton could represent a credible alternative for the precision
measurements of ``Phase II'' and aim at significantly new results in neutrino
astroparticle and non-accelerator-based particle physics (e.g. proton decay).Comment: 31 pages, 14 figure
Neutrino-2008: Where are we? Where are we going?
Our present knowledge of neutrinos can be summarized in terms of the
"standard neutrino scenario". Phenomenology of this scenario as well as
attempts to uncover physics behind neutrino mass and mixing are described.
Goals of future studies include complete reconstruction of the neutrino mass
and flavor spectrum, further test of the standard scenario and search for new
physics beyond it. Developments of new experimental techniques may lead to
construction of new neutrino detectors from table-top to multi-Megaton scales
which will open new horizons in the field. With detection of neutrino bursts
from the Galactic supernova and high energy cosmic neutrinos neutrino
astrophysics will enter qualitatively new phase. Neutrinos and LHC (and future
colliders), neutrino astronomy, neutrino structure of the Universe, and
probably, neutrino technologies will be among leading topics of research.Comment: 15 pages, 7 figures, Invited talk at the XXIII International
Conference on Neutrino Physics and Astrophysics, Christchurch, New Zealand,
May 25 - 31, 200
Neodymium isotope constraints on provenance, dispersal, and climate-driven supply of Zambezi sediments along the Mozambique Margin during the past ∼45,000 years
Marine sediments deposited off the Zambezi River that drains a considerable part of the southeast African continent provide continuous records of the continental climatic and environmental conditions.
Here we present time series of neodymium (Nd) isotope signatures of the detrital sediment fraction during the past ~45,000 years, to reconstruct climate-driven changes in the provenance of clays deposited along the Mozambique Margin. Coherent with the surface current regime, the Nd isotope distribution in surface sediments reveals mixing of the alongshore flowing Zambezi suspension load with sediments supplied by smaller rivers located further north. To reconstruct past changes in sediment provenances, Nd isotope signatures
of clays that are not significantly fractionated during weathering processes have been obtained from core 64PE304-80, which was recovered just north of the Zambezi mouth at 1329 m water depth. Distinctly unradiogenic clay signatures (ENd values <214.2) are found during the Last Glacial Maximum, Heinrich Stadial 1, and Younger Dryas. In contrast, the Nd isotope record shows higher, more radiogenic isotope signatures during Marine Isotope Stage 3 and between ~15 and ~5 ka BP, the latter coinciding with the timing of the northern hemisphere African Humid Period. The clay-sized sediment fraction with the least radiogenic Nd isotope signatures was deposited during the Holocene, when the adjacent Mozambique Shelf became completely flooded. In general, the contribution of the distinctly unradiogenic Zambezi suspension load has followed the intensity of precession-forced monsoonal precipitation and enhanced during periods of increased southern hemisphere insolation and high-latitude northern hemispheric climate
variability
The reconstruction software for the MICE scintillating fibre trackers
The Muon Ionization Cooling Experiment (MICE) will demonstrate the principle of muon beam phase-space reduction via ionization cooling. Muon beam cooling will be required for the proposed Neutrino Factory or Muon Collider. The phase-space before and after the cooling cell must be measured precisely. This is achieved using two scintillating-fibre trackers, each placed in a solenoidal magnetic field. This paper describes the software reconstruction for the fibre trackers: the GEANT4 based simulation; the implementation of the geometry; digitisation; space-point reconstruction; pattern recognition; and the final track fit based on a Kalman filter. The performance of the software is evaluated by means of Monte Carlo studies and the precision of the final track reconstruction is evaluated
A combined beta-beam and electron capture neutrino experiment
The next generation of long baseline neutrino experiments will aim at
determining the value of the unknown mixing angle, theta_{13}, the type of
neutrino mass hierarchy and the presence of CP-violation in the lepton sector.
Beta-beams and electron capture experiments have been studied as viable
candidates for long baseline experiments. They use a very clean electron
neutrino beam from the beta-decays or electron capture decays of boosted ions.
In the present article we consider an hybrid setup which combines a beta-beam
with an electron capture beam by using boosted Ytterbium ions. We study the
sensitivity to the CP-violating phase delta and the theta_{13} angle, the
CP-discovery potential and the reach to determine the type of neutrino mass
hierarchy for this type of long baseline experiment. The analysis is performed
for different neutrino beam energies and baselines. Finally, we also discuss
how the results would change if a better knowledge of some of the assumed
parameters was achieved by the time this experiment could take place.Comment: 35 pp, 11 fig
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