13 research outputs found
Neutrino mass generation in the SO(4) model
Generation of neutrino mass in SO(4) model is proposed here. The algebraic
structure of SO(4) is same as to that of . It is
shown that the spontaneous symmetry breaking results three massive as well as
three massless gauge bosons. The standard model theory according to which there
exist three massive gauge bosons and a massless one is emerged from this model.
In the framework of a small Dirac neutrino mass is
derived. It is also shown that such mass term may vanish with a special choice.
The Majorana mass term is not considered here and thus in this model the
neutrino mass does not follow seesaw structure.Comment: 7 pages, no figur
Neutrino Bremsstrahlung Process in highly degenerate magnetized electron gas
In this article the neutrino bremsstrahlung process is considered in presence
of strong magnetic field, though the calculations for this process in absence
of magnetic field are also carried out simultaneously. The electrons involved
in this process are supposed to be highly degenerate and relativistic. The
scattering cross sections and energy loss rates for both cases, in presence and
absence of magnetic field, are calculated in the extreme-relativistic limit.
Two results are compared in the range of temperature K K and magnetic field G at a fixed density
, a typical environment during the cooling of magnetized
neutron star. The interpretation of our result is briefly discussed and the
importance of this process during the stellar evolution is speculated.Comment: 12 pages including 2 figures and 1 tabl
Electron-Neutrino Bremsstrahlung in Electro-Weak Theory
The electron-neutrino bremsstrahlung process has been considered in the
framework of electro-weak theory. The scattering cross section has been
calculated in the center of mass frame and approximated to extreme relativistic
as well as non-relativistic case. The rate of energy-loss via this type of
bremsstrahlung process has been obtained both in non-degenerate and degenerate
region. The effect of this electron-neutrino bremsstrahlung process in
different ranges of temperature and density characterizing the late stages of
stellar evolution has been discussed. It is found from our study that this
bremsstrahlung process is highly important in the non-degenerate region,
although it might have some significant effect in the extreme relativistic
degenerate region.Comment: 18 pages including 4 figures and 1 table; Published in J. Phys
Accelerated motion in general relativity: fate of the singularity
Under general relativity, the paths of accelerated test particles are taken into account. It is examined whether such accelerations have any influence on the ‘singularity’ of the spacetime. The Raychaudhuri equation for the congruence of the time-like curves describing the paths of the accelerated particles is considered to calculate a few physical attributes. It is shown that if the acceleration of the test particles exceeds a particular value, then the congruences of the accelerated time-like curves do not encounter any singularity although the usual energy conditions are violated or modified. It is shown further that in the curved spacetime of general relativistic framework one may generate a system of transformations that is a generalization of the Rindler coordinates related to accelerated frame in the flat Minkowski spacetime. To show the influence of the acceleration of test particle on singularity of a particular spacetime the Schwarzschild spacetime is considered. Taking tidal deviation related acceleration term, it is shown that the acceleration may attain a specific value for which the modified Kretschmann scalar vanishes in a spherical neighbourhood of the singularity and thus the Schwarzschild singularity disappears. In the context of singularity as ‘geodesic incompleteness’ of the spacetime manifold it is also proved that prescribing an appropriate acceleration term on the maximal geodesic defined in a finite interval one may extend it up to infinite proper time and hence the spacetime becomes singularity free. Such results hold at the price of violating the usual energy conditions