16 research outputs found
Lepton asymmetries and the growth of cosmological seed magnetic fields
Primordial cosmological hypermagnetic fields polarize the early
Universe plasma prior to the electroweak phase transition (EWPT).
As a result of the long range parity violating gauge interaction present in
the Standard Model their magnitude gets amplified, opening a new, perturbative
way, of accounting for the observed intergalactic magnetic fields.Comment: 4 pages, no figures, final published version available online at
http://www.iop.org/EJ/abstract/1029-8479/2008/03/06
Chern-Simons anomaly as polarization effect
The parity violating Chern-Simons term in the epoch before the electroweak
phase transition can be interpreted as a polarization effect associated to
massless right-handed electrons (positrons) in the presence of a large-scale
seed hypermagnetic field. We reconfirm the viability of a unified seed field
scenario relating the cosmological baryon asymmetry and the origin of the
protogalactic large-scale magnetic fields observed in astronomy.Comment: 4 pages, latex, matches published versio
Black holes as antimatter factories
We consider accretion of matter onto a low mass black hole surrounded by
ionized medium. We show that, because of higher mobility of protons than
electrons, the black hole would acquire positive electric charge. If the black
hole's mass is about or below g, the electric field at the horizon
can reach the critical value which leads to vacuum instability and
electron--positron pair production by the Schwinger mechanism. Since the
positrons are ejected by the emergent electric field, while electrons are
back--captured, the black hole operates as an antimatter factory which
effectively converts protons into positrons.Comment: 5 pages, no figure. v2: with discussion section not included in the
refereed versio
Renormalization of the P- and T-odd nuclear potentials by the strong interaction and enhancement of P-odd effective field
Approximate analytical formulas for the self-consistent renormalization of
P,T-odd and P-odd weak nuclear potentials by the residual nucleon-nucleon
strong interaction are derived. The contact spin-flip nucleon-nucleon
interaction reduces the constant of the P,T-odd potential 1.5 times for the
proton and 1.8 times for the neutron. Renormalization of the P-odd potential is
caused by the velocity dependent spin-flip component of the strong interaction.
In the standard variant of -exchange, the conventional strength
values lead to anomalous enhancement of the P-odd potential. Moreover, the
-meson exchange contribution seems to be large enough to generate an
instability (pole) in the nuclear response to a weak potential.Comment: 5 pages, Revtex3, no figure
Effects of T- and P-odd weak nucleon interaction in nuclei: renormalizations due to residual strong interaction, matrix elements between compound states and their correlations with P-violating matrix elements
Manifestations of P-,T-odd weak interaction between nucleons in nucleus are
considered. Renormalization of this interaction due to residual strong
interaction is studied. Mean squared matrix elements of P-,T-odd weak
interaction between compound states are calculated. Correlators between
P-,T-odd and P-odd, T-even weak interaction matrix elements between compound
states are considered and estimates for these quantities are obtained.Comment: Submitted to Phys. Rev. C; 21 pages, REVTEX 3, no figure
Magnetic Field Amplification in Galaxy Clusters and its Simulation
We review the present theoretical and numerical understanding of magnetic
field amplification in cosmic large-scale structure, on length scales of galaxy
clusters and beyond. Structure formation drives compression and turbulence,
which amplify tiny magnetic seed fields to the microGauss values that are
observed in the intracluster medium. This process is intimately connected to
the properties of turbulence and the microphysics of the intra-cluster medium.
Additional roles are played by merger induced shocks that sweep through the
intra-cluster medium and motions induced by sloshing cool cores. The accurate
simulation of magnetic field amplification in clusters still poses a serious
challenge for simulations of cosmological structure formation. We review the
current literature on cosmological simulations that include magnetic fields and
outline theoretical as well as numerical challenges.Comment: 60 pages, 19 Figure