26 research outputs found
Science Potential of a Deep Ocean Antineutrino Observatory
This paper presents science potential of a deep ocean antineutrino
observatory under development at Hawaii. The observatory design allows for
relocation from one site to another. Positioning the observatory some 60 km
distant from a nuclear reactor complex enables precision measurement of
neutrino mixing parameters, leading to a determination of neutrino mass
hierarchy. At a mid-Pacific location the observatory measures the flux and
ratio of uranium and thorium decay neutrinos from earth's mantle and performs a
sensitive search for a hypothetical natural fission reactor in earth's core. A
subsequent deployment at another mid-ocean location would test lateral
heterogeneity of uranium and thorium in earth's mantle.Comment: 3 pages- paper presented at NOW 2006, Lecce, Ital
Geo-neutrinos and Silicate Earth Enrichment of U and Th
The terrestrial distribution of U, Th, and K abundances governs the thermal
evolution, traces the differentiation, and reflects the bulk composition of the
earth. Comparing the bulk earth composition to chondritic meteorites estimates
the net amounts of these radiogenic heat-producing elements available for
partitioning to the crust, mantle, and core. Core formation enriches the
abundances of refractory lithophile elements, including U and Th, in the
silicate earth by ~1.5. Global removal of volatile elements potentially
increases this enrichment to ~2.8. The K content of the silicate earth follows
from the ratio of K to U. Variable enrichment produces a range of possible
heat-producing element abundances in the silicate earth. A model assesses the
essentially fixed amounts of U, Th, and K in the approximately closed crust
reservoir. Subtracting these sequestered crustal amounts from the variable
amounts in the silicate earth results in a range of possible mantle
allocations, leaving global dynamics and thermal evolution poorly constrained.
Terrestrial antineutrinos from {\beta}-emitting daughter nuclei in the U and Th
decay series traverse the earth with negligible attenuation. The rate at which
large subsurface instruments observe these geo-neutrinos depends on the
distribution of U and Th relative to the detector. Geo-neutrino observations
with sensitivity to U and Th in the mantle are able to estimate silicate earth
enrichment, leading to a more complete understanding of the origin, accretion,
differentiation, and thermal history of the planet.Comment: published version: 21 pages, 3 figures, 5 table
Solar Neutrinos and the Principle of Equivalence
We study the proposed solution of the solar neutrino problem which requires a
flavor nondiagonal coupling of neutrinos to gravity. We adopt a
phenomenological point of view and investigate the consequences of the
hypothesis that the neutrino weak interaction eigenstates are linear
combinations of the gravitational eigenstates which have slightly different
couplings to gravity, and , , corresponding to a
difference in red-shift between electron and muon neutrinos, . We perform a analysis of the latest available solar
neutrino data and obtain the allowed regions in the space of the relevant
parameters. The existing data rule out most of the parameter space which can be
probed in solar neutrino experiments, allowing only for small values of the mixing angle () and for large mixing (). Measurements of the -neutrino energy spectrum in the SNO and
Super-Kamiokande experiments will provide stronger constraints independent of
all considerations related to solar models. We show that these measurements
will be able to exclude part of the allowed region as well as to distinguish
between conventional oscillations and oscillations due to the violation of the
equivalence principle.Comment: 20 pages + 4 figures, IASSNS-AST 94/5
Observational Constraints on Chaplygin Quartessence: Background Results
We derive the constraints set by several experiments on the quartessence
Chaplygin model (QCM). In this scenario, a single fluid component drives the
Universe from a nonrelativistic matter-dominated phase to an accelerated
expansion phase behaving, first, like dark matter and in a more recent epoch
like dark energy. We consider current data from SNIa experiments, statistics of
gravitational lensing, FR IIb radio galaxies, and x-ray gas mass fraction in
galaxy clusters. We investigate the constraints from this data set on flat
Chaplygin quartessence cosmologies. The observables considered here are
dependent essentially on the background geometry, and not on the specific form
of the QCM fluctuations. We obtain the confidence region on the two parameters
of the model from a combined analysis of all the above tests. We find that the
best-fit occurs close to the CDM limit (). The standard
Chaplygin quartessence () is also allowed by the data, but only at
the level.Comment: Replaced to match the published version, references update
The Pharmacogenetics Research Network: From SNP Discovery to Clinical Drug Response
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109975/1/cpt6100087.pd
Testing the Vacuum Oscillation and the MSW Solutions of the Solar Neutrino Problem
Solar model independent tests of the vacuum oscillation and MSW solutions of
the solar neutrino problem are considered. Detailed predictions for time
(seasonal) variations of the signals in the future solar neutrino detectors
(SNO, Super Kamiokande, BOREXINO, HELLAZ), if solar neutrinos take part in
vacuum oscillations, are given. Results on the distortions of the spectra of
boron neutrinos, and of electrons from the neutrino-electron scattering induced
by boron neutrinos, in the cases of vacuum oscillations or MSW transitions are
presented for a large number of values of the relevant parameters. The
possibilities to distinguish between the vacuum oscillation, the MSW adiabatic,
and the MSW nonadiabatic transitions (solutions) in the future solar neutrino
experiments are discussed.Comment: 26 p + 7 figures (available upon request from
[email protected]), SISSA 41/94/EP and IFP-295-UN
Neutrino mass spectrum from the results of neutrino oscillation experiments
All the possible schemes of neutrino mixing with four massive neutrinos
inspired by the existing experimental indications in favor of neutrino mixing
are considered in a model independent way. Assuming that in short-baseline
experiments only one mass-squared difference is relevant, it is shown that the
scheme with a neutrino mass hierarchy is not compatible with the experimental
results. Only two schemes with two pairs of neutrinos with close masses
separated by a mass difference of the order of 1 eV are in agreement with the
results of all experiments. One of these schemes leads to possibly observable
effects in Tritium and neutrinoless double-beta decay experiments.Comment: Latex2e file, 13 pages including 2 figures. Postscript also available
at http://www.to.infn.it/teorici/giunti/papers.htm
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The forward physics facility at the high-luminosity LHC
High energy collisions at the High-Luminosity Large Hadron Collider (LHC) produce a large number of particles along the beam collision axis, outside of the acceptance of existing LHC experiments. The proposed Forward Physics Facility (FPF), to be located several hundred meters from the ATLAS interaction point and shielded by concrete and rock, will host a suite of experiments to probe standard model (SM) processes and search for physics beyond the standard model (BSM). In this report, we review the status of the civil engineering plans and the experiments to explore the diverse physics signals that can be uniquely probed in the forward region. FPF experiments will be sensitive to a broad range of BSM physics through searches for new particle scattering or decay signatures and deviations from SM expectations in high statistics analyses with TeV neutrinos in this low-background environment. High statistics neutrino detection will also provide valuable data for fundamental topics in perturbative and non-perturbative QCD and in weak interactions. Experiments at the FPF will enable synergies between forward particle production at the LHC and astroparticle physics to be exploited. We report here on these physics topics, on infrastructure, detector, and simulation studies, and on future directions to realize the FPF's physics potential
Search for long-lived neutral particles in pp collisions at s√=13 TeV that decay into displaced hadronic jets in the ATLAS calorimeter
This paper describes a search for pairs of neutral, long-lived particles decaying in the ATLAS calorimeter. Long-lived particles occur in many extensions to the Standard Model and may elude searches for new promptly decaying particles. The analysis considers neutral, long-lived scalars with masses between 5 and 400 GeV, produced from decays of heavy bosons with masses between 125 and 1000 GeV, where the long-lived scalars decay into Standard Model fermions. The analysis uses either 10.8 fb−1
or 33.0 fb−1 of data (depending on the trigger) recorded in 2016 at the LHC with the ATLAS detector in proton–proton collisions at a centre-of-mass energy of 13 TeV. No significant excess is observed, and limits are reported on the production cross section times branching ratio as a function of the proper decay length of the long-lived particles