1,469 research outputs found
Angular momentum non-conserving decays in isotropic media
Various processes that are forbidden in the vacuum due to angular momentum
conservation can occur in a medium that is isotropic and does not carry any
angular momentum. We illustrate this by considering explicitly two examples.
The first one is the decay of a spin-0 particle into a photon and another
spin-0 particle, using a model involving the Yukawa interactions of the scalar
particles with a charged fermion field. The second one involves the decay of a
neutrino into another neutrino and a graviton, in the standard model of
particle interactions augmented with the linearized gravitational couplings.Comment: 22 pages, Latex, uses axodraw.sty. 3 figures embedded in the tex
file. This paper contains the same material as that presented in two earlier
papers, arXiv:0901.2981 and arXiv:0901.2982, written by us. This version
supersedes those two paper
Recommended from our members
Switch for inductive energy store transfer circuit
A switch for use in an inductive energy store transfer circuit utilizes a quantity of electrically conductive liquid bidirectionally flowable between a position that establishes electrical connection between electrodes and a position that opens electrical connection between the electrodes. High pressure gas biases the liquid to a position that establishes electrical connection between the electrodes, and yieldably resists movement of the liquid toward the position that opens electrical connection between the electrodes. Current through the switch electrodes produces a magnetic force that acts on the liquid and urges it toward the position that opens electrical connection between the electrodes. Switching action occurs upon a predetermined magnitude of current being attained.Board of Regents, University of Texas Syste
ECONOMIC ANALYSIS OF TEMIK ON CITRUS IN THE INDIAN RIVER AREA IN SOUTHEASTERN FLORIDA
Temik [R](aldicarb) is a pesticide labeled for use on several citrus crops to control rust mite, whitefly, nematode and brown citrus aphid pests. Analysis of previous research experiments indicates that this pesticide is beneficial to both orange and grapefruit production and that both cost savings and higher yields can be experienced in many types of groves. Actual grove data shows that net returns for mature grapefruit that receive Temik [R] can be $500 per acre greater than net returns for identical acreage that uses other pest control options. Also, based on grove reset data it is shown that with an application of Temik [R] the resulting increased yields for three-year-old trees more than cover the additional cost of applying the Temik [R].mature citrus, resets, revenue-cost, net return, grapefruit, Crop Production/Industries,
A feasibility study of a hypersonic real-gas facility
A four month feasibility study of a hypersonic real-gas free flight test facility for NASA Langley Research Center (LARC) was performed. The feasibility of using a high-energy electromagnetic launcher (EML) to accelerate complex models (lifting and nonlifting) in the hypersonic, real-gas facility was examined. Issues addressed include: design and performance of the accelerator; design and performance of the power supply; design and operation of the sabot and payload during acceleration and separation; effects of high current, magnetic fields, temperature, and stress on the sabot and payload; and survivability of payload instrumentation during acceleration, flight, and soft catch
A study of the applicability/compatibility of inertial energy storage systems to future space missions
The applicability/compatibility of inertial energy storage systems like the homopolar generator (HPG) and the compensated pulsed alternator (CPA) to future space missions is explored. Areas of CPA and HPG design requiring development for space applications are identified. The manner in which acceptance parameters of the CPA and HPG scale with operating parameters of the machines are explored and the types of electrical loads which are compatible with the CPA and HPG are examined. Potential applications including the magnetoplasmadynamic (MPD) thruster, pulsed data transmission, laser ranging, welding and electromagnetic space launch are discussed
Gauge Independence of Limiting Cases of One-Loop Electron Dispersion Relation in High-Temperature QED
Assuming high temperature and taking subleading temperature dependence into
account, gauge dependence of one-loop electron dispersion relation is
investigated in massless QED at zero chemical potential. The analysis is
carried out using a general linear covariant gauge. The equation governing the
gauge dependence of the dispersion relation is obtained and used to prove that
the dispersion relation is gauge independent in the limiting case of momenta
much larger than . It is also shown that the effective mass is not
influenced by the leading temperature dependence of the gauge dependent part of
the effective self-energy. As a result the effective mass, which is of order
, does not receive a correction of order from one loop, independent
of the gauge parameter.Comment: Revised and enlarged version, 14 pages, Revte
On finite--temperature and --density radiative corrections to the neutrino effective potential in the early Universe
Finite-temperature and -density radiative corrections to the neutrino
effective potential in the otherwise CP-symmetric early Universe are considered
in the real-time approach of Thermal Field Theory. A consistent perturbation
theory endowed with the hard thermal loop resummation techniques developed by
Braaten and Pisarski is applied. Special attention is focused on the question
whether such corrections can generate any nonzero contribution to the
CP-symmetric part of the neutrino potential, if the contact approximation for
the W-propagator is used.Comment: 11 pages, revtex styl
The Boltzmann Equation in Scalar Field Theory
We derive the classical transport equation, in scalar field theory with a
V(phi) interaction, from the equation of motion for the quantum field. We
obtain a very simple, but iterative, expression for the effective action which
generates all the n-point Green functions in the high-temperature limit. An
explicit closed form is given in the static case.Comment: 10 pages, using RevTeX (corrected TeX misprints
- …