676 research outputs found
On the Possible Enhancement of the Magnetic Field by Neutrino Reemission Processes in the Mantle of a Supernova
URCA neutrino reemission processes under the conditions in the mantle of a
supernova with a strong toroidal magnetic field are investigated. It is shown
that parity violation in these processes can be manifested macroscopically as a
torque that rapidly spins up the region of the mantle occupied by such a field.
Neutrino spin-up of the mantle can strongly affect the mechanism of further
generation of the toroidal field, specifically, it can enhance the field in a
small neighborhood of the rigid-body-rotating core of the supernova remnant.Comment: 8 pages, late
Pulsar Kicks With Sterile Neutrinos and Landau Levels
We use a model with two sterile neutrinos obtained by fits to the MiniBoone
and LSND experiments. Using formulations with neutrinos created by URCA
Processes in a strong magnetic field, so the lowest Landau level has a sizable
probability, we find that with known paramenters the assymetric sterile
neutrino emissivity might account for large pulsar kicks.Comment: 3 pages, 1 figur
Compensation method of geodynamic trend in the systems of geoelectric control
Compensation method of geodynamic trend in the systems of geoelectric control To ensure the safety of important national economic objects in the conditions of technogenic, biogenic and anthropogenic interference, it is advisable to carry out automated electromagnetic control of geodynamic processes on the basis of multipolar sensing system
Analysis of noise characteristics of multichannel systems of the formation of signals of georadars with synthesized aperture
The noise characteristics of multichannel systems of forming signals based on hybrid frequency synthesizers with automatic compensation of phase distortions of direct digital synthesizers, which are used in the composition of georadars with synthesized aperture, are investigate
Pulsar kicks from neutrino oscillations
Neutrino oscillations in a core-collapse supernova may be responsible for the
observed rapid motions of pulsars. Given the present bounds on the neutrino
masses, the pulsar kicks require a sterile neutrino with mass 2-20 keV and a
small mixing with active neutrinos. The same particle can be the cosmological
dark matter. Its existence can be confirmed the by the X-ray telescopes if they
detect a 1-10 keV photon line from the decays of the relic sterile neutrinos.
In addition, one may be able to detect gravity waves from a pulsar being
accelerated by neutrinos in the event of a nearby supernova.Comment: invited review article to appear in Int. J. Mod. Phys. (21 pages, 6
figures
Asymmetric neutrino emision and formation of rapidly moving pulsars
The neutron star formation during the collapse with the strong magnetic field
may lead to a mirror symmetry violation and formation of an asymmetric magnetic
field. Dependence of the week interaction cross-section on the magnetic field
strength lead to the asymmetric neutrino flux and formation of rapidly mooving
pulsars due to the recoil action as well as rapidly moving black holes.Comment: 8 pages, TeX, No figures. No macrose
Detecting sterile dark matter in space
Space-based instruments provide new and, in some cases, unique opportunities
to search for dark matter. In particular, if dark matter comprises sterile
neutrinos, the x ray detection of their decay line is the most promising
strategy for discovery. Sterile neutrinos with masses in the keV range could
solve several long-standing astrophysical puzzles, from supernova asymmetries
and the pulsar kicks to star formation, reionization, and baryogenesis. The
best current limits on sterile neutrinos come from Chandra and XMM-Newton.
Future advances can be achieved with a high-resolution x-ray spectrometry in
space.Comment: 11 pages, 1 figure, to appear in proceedings "From Quantum to Cosmos:
fundametal physics research in space", Washington, DC, May 22-24, 200
Diffusion doping route to plasmonic Si/SiOx nanoparticles
International audienceSemiconductor nanoparticles (SNPs) are a valuable building block for functional materials. Capabilities for engineering of electronic structure of SNPs can be further improved with development of techniques of doping by diffusion, as post-synthetic introduction of impurities does not affect the nucleation and growth of SNPs. Diffusion of dopants from an external source also potentially allows for temporal control of radial distribution of impurities. In this paper we report on the doping of Si/SiOx SNPs by annealing particles in gaseous phosphorus. The technique can provide efficient incorporation of impurities, controllable with precursor vapor pressure. HRTEM and X-ray diffraction studies confirmed that obtained particles retain their nanocrystallinity. Elemental analysis revealed doping levels up to 10%. Electrical activity of the impurity was confirmed through thermopower measurements and observation of localized surface plasmon resonance in IR spectra. The plasmonic behavior of etched particles and EDX elemental mapping suggest uniform distribution of phosphorus in the crystalline silicon cores. Impurity activation efficiencies up to 34% were achieved, which indicate high electrical activity of thermodynamically soluble phosphorus in oxide-terminated nanosilicon
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