9,304 research outputs found
Neutrinos with Lorentz-violating operators of arbitrary dimension
The behavior of fermions in the presence of Lorentz and CPT violation is
studied. Allowing for operators of any mass dimension, we classify all
Lorentz-violating terms in the quadratic Lagrange density for free fermions.
The result is adapted to obtain the effective hamiltonian describing the
propagation and mixing of three flavors of left-handed neutrinos in the
presence of Lorentz violation involving operators of arbitrary mass dimension.
A characterization of the neutrino coefficients for Lorentz violation is
provided via a decomposition using spin-weighted spherical harmonics. The
restriction of the general theory to various special cases is discussed,
including among others the renormalizable limit, the massless scenario,
flavor-blind and oscillation-free models, the diagonalizable case, and several
isotropic limits. The formalism is combined with existing data on neutrino
oscillations and kinematics to extract a variety of measures of coefficients
for Lorentz and CPT violation. For oscillations, we use results from the
short-baseline experiments LSND and MiniBooNE to obtain explicit sensitivities
to effects from flavor-mixing Lorentz-violating operators up to mass dimension
10, and we present methods to analyze data from long-baseline experiments. For
propagation, we use time-of-flight measurements from the supernova SN1987A and
from a variety of experiments including MINOS and OPERA to constrain
oscillation-free Lorentz-violating operators up to mass dimension 10, and we
discuss constraints from threshold effects in meson decays and Cherenkov
emission.Comment: 35 pages two-column REVTe
Radiative Corrections to Longitudinal and Transverse Gauge Boson and Higgs Production
Radiative corrections to gauge boson and Higgs production computed recently
using soft-collinear effective theory (SCET) require the one-loop high-scale
matching coefficients in the standard model. We give explicit expressions for
the matching coefficients for the effective field theory (EFT) operators for q
qbar -> VV and q qbar -> phi^+ phi for a general gauge theory with an arbitrary
number of gauge groups. The group theory factors are given explicitly for the
standard model, including both QCD and electroweak corrections.Comment: 16 pages, 49 figure
Transient Pressures from Compression of Discrete Air Pockets in Rapidly Filling Combined Sewer Storage Tunnels
https://deepblue.lib.umich.edu/bitstream/2027.42/154163/1/39015099114905.pd
Calcium-dependent hormonal regulation of amino acid transport and cyclic AMP accumulation in rat hepatocyte monolayer cultures.
New Constraints on Neutralino Dark Matter in the Supersymmetric Standard Model
We investigate the prospects for neutralino dark matter within the
Supersymmetric Standard Model (SSM) including the constraints from universal
soft supersymmetry breaking and radiative breaking of the electroweak symmetry.
The latter is enforced by using the one-loop Higgs effective potential which
automatically gives the one-loop corrected Higgs boson masses. We perform an
exhaustive search of the allowed five-dimensional parameter space and find that
the neutralino relic abundance depends most strongly on the
ratio . For the relic abundance is almost
always much too large, whereas for the opposite occurs. For
there are wide ranges of the remaining parameters for which
. We also determine that m_{\tilde q}\gsim250\GeV and
m_{\tilde l}\gsim100\GeV are necessary in order to possibly achieve
. These lower bounds are much weaker than the corresponding
ones derived previously when radiative breaking was {\it not} enforced.Comment: 12 pages plus 6 figures (not included), CERN-TH.6584/92,
CTP-TAMU-56/92, UAHEP921
Pseudo-transient Continuation, Solution Update Methods, and CFL Strategies for DG Discretizations of the RANS-SA Equations
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106459/1/AIAA2013-2686.pd
NELIOTA: The wide-field, high-cadence lunar monitoring system at the prime focus of the Kryoneri telescope
We present the technical specifications and first results of the ESA-funded,
lunar monitoring project "NELIOTA" (NEO Lunar Impacts and Optical TrAnsients)
at the National Observatory of Athens, which aims to determine the
size-frequency distribution of small Near-Earth Objects (NEOs) via detection of
impact flashes on the surface of the Moon. For the purposes of this project a
twin camera instrument was specially designed and installed at the 1.2 m
Kryoneri telescope utilizing the fast-frame capabilities of scientific
Complementary Metal-Oxide Semiconductor detectors (sCMOS). The system provides
a wide field-of-view (17.0' 14.4') and simultaneous observations in
two photometric bands (R and I), reaching limiting magnitudes of 18.7 mag in 10
sec in both bands at a 2.5 signal-to-noise level. This makes it a unique
instrument that can be used for the detection of NEO impacts on the Moon, as
well as for any astronomy projects that demand high-cadence multicolor
observations. The wide field-of-view ensures that a large portion of the Moon
is observed, while the simultaneous, high-cadence, monitoring in two
photometric bands makes possible, for the first time, the determination of the
temperatures of the impacts on the Moon's surface and the validation of the
impact flashes from a single site. Considering the varying background level on
the Moon's surface we demonstrate that the NELIOTA system can detect NEO impact
flashes at a 2.5 signal-to-noise level of ~12.4 mag in the I-band and R-band
for observations made at low lunar phases ~0.1. We report 31 NEO impact flashes
detected during the first year of the NELIOTA campaign. The faintest flash was
at 11.24 mag in the R-band (about two magnitudes fainter than ever observed
before) at lunar phase 0.32. Our observations suggest a detection rate of events .Comment: Accepted for publication in A&
Isospin properties of electric dipole excitations in 48Ca
Two different experimental approaches were combined to study the electric
dipole strength in the doubly-magic nucleus 48Ca below the neutron threshold.
Real-photon scattering experiments using bremsstrahlung up to 9.9 MeV and
nearly mono-energetic linearly polarized photons with energies between 6.6 and
9.51 MeV provided strength distribution and parities, and an
(\alpha,\alpha'\gamma) experiment at E_{\alpha}=136 MeV gave cross sections for
an isoscalar probe. The unexpected difference observed in the dipole response
is compared to calculations using the first-order random-phase approximation
and points to an energy-dependent isospin character. A strong isoscalar state
at 7.6 MeV was identified for the first time supporting a recent theoretical
prediction.Comment: 6 pages, 5 figures, as accepted in Phys. Lett.
Collisional damping rates for plasma waves
The distinction between the plasma dynamics dominated by collisional
transport versus collective processes has never been rigorously addressed until
recently. A recent paper [Yoon et al., Phys. Rev. E 93, 033203 (2016)]
formulates for the first time, a unified kinetic theory in which collective
processes and collisional dynamics are systematically incorporated from first
principles. One of the outcomes of such a formalism is the rigorous derivation
of collisional damping rates for Langmuir and ion-acoustic waves, which can be
contrasted to the heuristic customary approach. However, the results are given
only in formal mathematical expressions. The present Brief Communication
numerically evaluates the rigorous collisional damping rates by considering the
case of plasma particles with Maxwellian velocity distribution function so as
to assess the consequence of the rigorous formalism in a quantitative manner.
Comparison with the heuristic ("Spitzer") formula shows that the accurate
damping rates are much lower in magnitude than the conventional expression,
which implies that the traditional approach over-estimates the importance of
attenuation of plasma waves by collisional relaxation process. Such a finding
may have a wide applicability ranging from laboratory to space and
astrophysical plasmas.Comment: 5 pages, 2 figures; Published in Physics of Plasmas, volume/Issue
23/6. Publisher: AIP Publishing LLC. Date: Jun 1, 2016. URL:
http://aip.scitation.org/doi/10.1063/1.4953802 Rights managed by AIP
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