1,101 research outputs found
Comparison of Fixed Burst Versus Decremental Burst Pacing for Termination of Ventricular Tachycardia
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72440/1/j.1540-8159.1993.tb01531.x.pd
Limits on Production of Magnetic Monopoles Utilizing Samples from the DO and CDF Detectors at the Tevatron
We present 90% confidence level limits on magnetic monopole production at the
Fermilab Tevatron from three sets of samples obtained from the D0 and CDF
detectors each exposed to a proton-antiproton luminosity of
(experiment E-882). Limits are obtained for the production cross-sections and
masses for low-mass accelerator-produced pointlike Dirac monopoles trapped and
bound in material surrounding the D0 and CDF collision regions. In the absence
of a complete quantum field theory of magnetic charge, we estimate these limits
on the basis of a Drell-Yan model. These results (for magnetic charge values of
1, 2, 3, and 6 times the minimum Dirac charge) extend and improve previously
published bounds.Comment: 18 pages, 17 figures, REVTeX
Superluminal neutrinos in long baseline experiments and SN1987a
Precise tests of Lorentz invariance in neutrinos can be performed using long
baseline experiments such as MINOS and OPERA or neutrinos from astrophysical
sources. The MINOS collaboration reported a measurement of the muonic neutrino
velocities that hints to super-luminal propagation, very recently confirmed at
6 sigma by OPERA. We consider a general parametrisation which goes beyond the
usual linear or quadratic violation considered in quantum-gravitational models.
We also propose a toy model showing why Lorentz violation can be specific to
the neutrino sector and give rise to a generic energy behaviour E^alpha, where
alpha is not necessarily an integer number. Supernova bounds and the preferred
MINOS and OPERA regions show a tension, due to the absence of shape distortion
in the neutrino bunch in the far detector of MINOS. The energy independence of
the effect has also been pointed out by the OPERA results.Comment: 22 pages, 7 figures; comment on Cherenkov emission added, version
matching JHEP published pape
Economic Analysis of Carryover Policies for the United States Wheat Industry
The Oklahoma Agricultural Experiment Station periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
Revealing three-dimensional structure of individual colloidal crystal grain by coherent x-ray diffractive imaging
We present results of a coherent x-ray diffractive imaging experiment
performed on a single colloidal crystal grain. The full three-dimensional (3D)
reciprocal space map measured by an azimuthal rotational scan contained several
orders of Bragg reflections together with the coherent interference signal
between them. Applying the iterative phase retrieval approach, the 3D structure
of the crystal grain was reconstructed and positions of individual colloidal
particles were resolved. As a result, an exact stacking sequence of hexagonal
close-packed layers including planar and linear defects were identified.Comment: 8 pages, 5 figure
Inconsistency of the MLE for the joint distribution of interval censored survival times and continuous marks
This paper considers the nonparametric maximum likelihood estimator (MLE) for
the joint distribution function of an interval censored survival time and a
continuous mark variable. We provide a new explicit formula for the MLE in this
problem. We use this formula and the mark specific cumulative hazard function
of Huang and Louis (1998) to obtain the almost sure limit of the MLE. This
result leads to necessary and sufficient conditions for consistency of the MLE
which imply that the MLE is inconsistent in general. We show that the
inconsistency can be repaired by discretizing the marks. Our theoretical
results are supported by simulations.Comment: 27 pages, 4 figure
Background Dependent Lorentz Violation: Natural Solutions to the Theoretical Challenges of the OPERA Experiment
To explain both the OPERA experiment and all the known phenomenological
constraints/observations on Lorentz violation, the Background Dependent Lorentz
Violation (BDLV) has been proposed. We study the BDLV in a model independent
way, and conjecture that there may exist a "Dream Special Relativity Theory",
where all the Standard Model (SM) particles can be subluminal due to the
background effects. Assuming that the Lorentz violation on the Earth is much
larger than those on the interstellar scale, we automatically escape all the
astrophysical constraints on Lorentz violation. For the BDLV from the effective
field theory, we present a simple model and discuss the possible solutions to
the theoretical challenges of the OPERA experiment such as the Bremsstrahlung
effects for muon neutrinos and the pion decays. Also, we address the Lorentz
violation constraints from the LEP and KamLAMD experiments. For the BDLV from
the Type IIB string theory with D3-branes and D7-branes, we point out that the
D3-branes are flavour blind, and all the SM particles are the conventional
particles as in the traditional SM when they do not interact with the
D3-branes. Thus, we not only can naturally avoid all the known phenomenological
constraints on Lorentz violation, but also can naturally explain all the
theoretical challenges. Interestingly, the energy dependent photon velocities
may be tested at the experiments.Comment: RevTex4, 14 pages, minor corrections, references adde
Improved Experimental Limits on the Production of Magnetic Monopoles
We present new limits on low mass accelerator-produced point-like Dirac
magnetic monopoles trapped and bound in matter surrounding the D\O collision
region of the Tevatron at Fermilab (experiment E-882). In the context of a
Drell-Yan mechanism, we obtain cross section limits for the production of
monopoles with magnetic charge values of 1, 2, 3, and 6 times the minimum Dirac
charge of the order of picobarns, some hundred times smaller than found in
similar previous Fermilab searches. Mass limits inferred from these cross
section limits are presented.Comment: 5 pages, 4 eps figures, REVTe
Looking for magnetic monopoles at LHC with diphoton events
Magnetic monopoles have been a subject of interest since Dirac established
the relation between the existence of monopoles and charge quantization. The
intense experimental search carried thus far has not met with success. The
Large Hadron Collider is reaching energies never achieved before allowing the
search for exotic particles in the TeV mass range. In a continuing effort to
discover these rare particles we propose here other ways to detect them. We
study the observability of monopoles and monopolium, a monopole-antimonopole
bound state, at the Large Hadron Collider in the channel for
monopole masses in the range 500-1000 GeV. We conclude that LHC is an ideal
machine to discover monopoles with masses below 1 TeV at present running
energies and with 5 fb of integrated luminosity.Comment: This manuscript contains information appeared in Looking for magnetic
monopoles at LHC, arXiv:1104.0218 [hep-ph] and Monopolium detection at the
LHC.,arXiv:1107.3684 [hep-ph] by the same authors, rewritten for joint
publication in The European Physica Journal Plus. 26 pages, 22 figure
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