44 research outputs found
Decoupling of Massive Right-handed Neutrinos
We investigate the effect of B+L - violating anomalous generation of massive
right-handed neutrinos on their decoupling, when the right-handed neutrino mass
is considerably greater than the right-handed gauge boson masses. Considering
normal annihilation channels, the Lee-Weinberg type of calculation, in this
case, gives an upper bound of about 700 Gev, which casts doubt on the existence
of such a right-handed neutrino mass greater than right-handed gauge boson
masses. We examine the possibility that a consideration of anomalous effects
related to the SU(2)_R gauge group may turn this into a lower bound of the
order of 100 Tev.Comment: 28 Pages, Latex, 2 figure
Inertial mechanism: dynamical mass as a source of particle creation
A kinetic theory of vacuum particle creation under the action of an inertial
mechanism is constructed within a nonpertrubative dynamical approach. At the
semi-phenomenological level, the inertial mechanism corresponds to quantum
field theory with a time-dependent mass. At the microscopic level, such a
dependence may be caused by different reasons: The non-stationary Higgs
mechanism, the influence of a mean field or condensate, the presence of the
conformal multiplier in the scalar-tensor gravitation theory etc. In what
follows, a kinetic theory in the collisionless approximation is developed for
scalar, spinor and massive vector fields in the framework of the oscillator
representation, which is an effective tool for transition to the quasiparticle
description and for derivation of non-Markovian kinetic equations. Properties
of these equations and relevant observables (particle number and energy
densities, pressure) are studied. The developed theory is applied here to
describe the vacuum matter creation in conformal cosmological models and
discuss the problem of the observed number density of photons in the cosmic
microwave background radiation. As other example, the self-consistent evolution
of scalar fields with non-monotonic self-interaction potentials (the
W-potential and Witten - Di Vecchia - Veneziano model) is considered. In
particular, conditions for appearance of tachyonic modes and a problem of the
relevant definition of a vacuum state are considered.Comment: 51 pages, 18 figures, submitted to PEPAN (JINR, Dubna); v2: added
reference