13 research outputs found
Instability of Quark Matter Core in a Compact Newborn Neutron Star With Moderately Strong Magnetic Field
It is explicitly shown that if phase transition occurs at the core of a
newborn neutron star with moderately strong magnetic field strength, which
populates only the electron's Landau levels, then in the -equilibrium
condition, the quark core is energetically much more unstable than the neutron
matter of identical physical condition.Comment: Six pages REVTEX file, one .eps file (included
Relativistic theory of inverse beta-decay of polarized neutron in strong magnetic field
The relativistic theory of the inverse beta-decay of polarized neutron, , in strong magnetic field is developed. For the proton
wave function we use the exact solution of the Dirac equation in the magnetic
filed that enables us to account exactly for effects of the proton momentum
quantization in the magnetic field and also for the proton recoil motion. The
effect of nucleons anomalous magnetic moments in strong magnetic fields is also
discussed. We examine the cross section for different energies and directions
of propagation of the initial neutrino accounting for neutrons polarization. It
is shown that in the super-strong magnetic field the totally polarized neutron
matter is transparent for neutrinos propagating antiparallel to the direction
of polarization. The developed relativistic approach can be used for
calculations of cross sections of the other URCA processes in strong magnetic
fields.Comment: 41 pages in LaTex including 11 figures in PostScript, discussion on
nucleons AMM interaction with magnetic field is adde
Weak reaction freeze-out constraints on primordial magnetic fields
We explore constraints on the strength of the primordial magnetic field based
upon the weak reaction freeze-out in the early universe. We find that limits on
the strength of the magnetic field found in other works are recovered simply by
examining the temperature at which the rate of weak reactions drops below the
rate of universal expansion ( H). The temperature for which the
ratio at freeze-out leads to acceptable helium production implies limits
on the magnetic field. This simplifies the application of magnetic fields to
other cosmological variants of the standard big-bang. As an illustration we
also consider effects of neutrino degeneracy on the allowed limits to the
primordial magnetic field.Comment: Submitted to Phys. Rev. D., 6 pages, 2 figure
Neutrino opacity in magnetised hot and dense nuclear matter
We study the neutrino interaction rates in hot matter at high densities in
the presence of uniform magnetic field. The neutrino cross-sections involving
both the charged current absorption and neutral current scattering reactions on
baryons and leptons have been considered. We have in particular considered the
interesting case when the magnetic field is strong enough to completely
polarise the protons and electrons in supernovae and neutron stars. The opacity
in such a situation is considerably modified and the cross-section develops
anisotropy. This has implications for phenomenon invoked in the literature to
explain the observed pulsar kicks.Comment: 22 latex pages and 7 postscript figure
Neutrino-Nucleon Interactions in Magnetized Neutron-Star Matter: The Effects of Parity Violation
We study neutrino-nucleon scattering and absorption in a dense, magnetized
nuclear medium. These are the most important sources of neutrino opacity
governing the cooling of a proto-neutron star in the first tens of seconds
after its formation. Because the weak interaction is parity violating, the
absorption and scattering cross-sections depend asymmetrically on the
directions of the neutrino momenta with respect to the magnetic field. We
develop the moment formalism of neutrino transport in the presence of such
asymmetric opacities and derive explicit expressions for the neutrino flux and
other angular moments of the Boltzmann transport equation. For a given neutrino
species, there is a drift flux of neutrinos along the magnetic field in
addition to the usual diffusive flux. This drift flux depends on the deviation
of the neutrino distribution function from thermal equilibrium. Hence, despite
the fact that the neutrino cross-sections are asymmetric throughout the star,
asymmetric neutrino flux can be generated only in the outer region of the
proto-neutron star where the neutrino distribution deviates significantly from
thermal equilibrium. In addition to the asymmetric absorption opacity arising
from nucleon polarization, we find the contribution of the electron (or
positron) ground state Landau level. For neutrinos of energy less than a few
times the temperature, this is the dominant source of asymmetric opacity.
Lastly, we discuss the implication of our result to the origin of pulsar kicks:
in order to generate kick velocity of a few hundred km/s from asymmetric
neutrino emission using the parity violation effect, the proto-neutron star
must have a dipole magnetic field of at least G.Comment: 35 pages, no figures, submitted to Phys.Rev.
Generation of high-energy particles, neutrino and fotons in magnetosphere of collapsing star
The generation of particles, photons and neutrinos in magnetosphere of collapsing star are considered. These processes are caused the self-interaction initial accelerating in magnetosphere protons and electrons. The second particles and photons will arise as a result of this self-interaction, which in turn will generate charged particles, photons and neutrino (cascade process). These processes are especially effective for the formation collapsing star magnetosphere from the secondary charged particles. In addition, the particles, photons and neutrinos will be generated in magnetosphere of collapsing star as result of these processes