544 research outputs found
Recoilless resonant neutrino capture and basics of neutrino oscillations
It is shown that the experiment on recoilless resonant emission and
absorption of , proposed recently by Raghavan, could have an
important impact on our understanding of the physics of neutrino oscillations.Comment: Additional information in the last chapte
A Compact Beam Stop for a Rare Kaon Decay Experiment
We describe the development and testing of a novel beam stop for use in a
rare kaon decay experiment at the Brookhaven AGS. The beam stop is located
inside a dipole spectrometer magnet in close proximity to straw drift chambers
and intercepts a high-intensity neutral hadron beam. The design process,
involving both Monte Carlo simulations and beam tests of alternative beam-stop
shielding arrangements, had the goal of minimizing the leakage of particles
from the beam stop and the resulting hit rates in detectors, while preserving
maximum acceptance for events of interest. The beam tests consisted of
measurements of rates in drift chambers, scintilation counter hodoscopes, a gas
threshold Cherenkov counter, and a lead glass array. Measurements were also
made with a set of specialized detectors which were sensitive to low-energy
neutrons, photons, and charged particles. Comparisons are made between these
measurements and a detailed Monte Carlo simulation.Comment: 39 pages, 14 figures, submitted to Nuclear Instruments and Method
Search for the Weak Decay of an H Dibaryon
We have searched for a neutral dibaryon decaying via and
. Our search has yielded two candidate events from which we set
an upper limit on the production cross section. Normalizing to the
inclusive production cross section, we find at 90% C.L., for an of mass
2.15 GeV/.Comment: 11 pages, 6 postscript figures, epsfig, aps, preprint, revte
Neutrino mass matrix with U(2) flavor symmetry and neutrino oscillations
The three neutrino mass matrices in the model are studied
focusing on the neutrino oscillation experiments. The atmospheric neutrino
anomaly could be explained by the large oscillation.
The long baseline experiments are expected to detect signatures of the neutrino
oscillation even if the atmospheric neutrino anomaly is not due to the neutrino
oscillation. However, the model cannot solve the solar neutrino deficit while
it could be reconciled with the LSND data.Comment: 12 pages, LaTex file, to be published in PR
Neutrino oscillation parameters from MINOS, ICARUS and OPERA combined
We perform a detailed analysis of the capabilities of the MINOS, ICARUS and
OPERA experiments to measure neutrino oscillation parameters at the atmospheric
scale with their data taken separately and in combination. MINOS will determine
and to within 10% at the 99% C.L. with
10 kton-years of data. While no one experiment will determine with much precision, if its value lies in the combined
sensitivity region of the three experiments, it will be possible to place a
lower bound of O(0.01) at the 95% C.L. on this parameter by combining the data
from the three experiments. The same bound can be placed with a combination of
MINOS and ICARUS data alone.Comment: Version to appear in PR
Web-Based Genome-Wide Association Study Identifies Two Novel Loci and a Substantial Genetic Component for Parkinson's Disease
Although the causes of Parkinson's disease (PD) are thought to be primarily environmental, recent studies suggest that a number of genes influence susceptibility. Using targeted case recruitment and online survey instruments, we conducted the largest case-control genome-wide association study (GWAS) of PD based on a single collection of individuals to date (3,426 cases and 29,624 controls). We discovered two novel, genome-wide significant associations with PD–rs6812193 near SCARB2 (, ) and rs11868035 near SREBF1/RAI1 (, )—both replicated in an independent cohort. We also replicated 20 previously discovered genetic associations (including LRRK2, GBA, SNCA, MAPT, GAK, and the HLA region), providing support for our novel study design. Relying on a recently proposed method based on genome-wide sharing estimates between distantly related individuals, we estimated the heritability of PD to be at least 0.27. Finally, using sparse regression techniques, we constructed predictive models that account for 6%–7% of the total variance in liability and that suggest the presence of true associations just beyond genome-wide significance, as confirmed through both internal and external cross-validation. These results indicate a substantial, but by no means total, contribution of genetics underlying susceptibility to both early-onset and late-onset PD, suggesting that, despite the novel associations discovered here and elsewhere, the majority of the genetic component for Parkinson's disease remains to be discovered
First Observation of the Rare Decay Mode K-long -> e+ e-
In an experiment designed to search for and study very rare two-body decay
modes of the K-long, we have observed four examples of the decay K-long -> e+
e-, where the expected background is 0.17+-0.10 events. This observation
translates into a branching fraction of 8.7^{+5.7}_{-4.1} X 10^{-12},
consistent with recent theoretical predictions. This result represents by far
the smallest branching fraction yet measured in particle physics.Comment: 9 pages, 3 figure
Possible Effects of Quantum Mechanics Violation Induced by Certain Quantum Gravity on Neutrino Oscillations
In this work we tried extensively to apply the EHNS postulation about the
quantum mechanics violation effects induced by the quantum gravity of black
holes to neutrino oscillations. The possibilities for observing such effects in
the neutrino experiments (in progress and/or accessible in the near future)
were discussed. Of them, an interesting one was outlined specially.Comment: 18 pages, 0 figure, (1 REVTeX file
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