Eur. Phys. J. C 19, 183-190
DOI: 10.1007/s100520100575
Decay and decoupling of heavy right-handed Majorana neutrinos in the L-R model
Paramita Adhya1, D. Rai Chaudhuri1 and Amitava Raychaudhuri21 Department of Physics, Presidency College, 86/1, College Street, Calcutta 700073, India
2 Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road, Calcutta 700009, India
paro27@hotmail.com
allrc@usa.net
amitava@cubmb.ernet.in
(Received: 1 November 2000 / Published online: 23 February 2001 -© Springer-Verlag 2001)
Abstract
Heavy right-handed neutrinos are of current interest. The
interactions and decay of such neutrinos determine their
decoupling epoch during the evolution of the universe. This in
turn affects various observable features like the energy density,
nucleosynthesis, CMBR spectrum, galaxy formation and
baryogenesis. Here, we consider reduction of right-handed
electron-type Majorana neutrinos, in the left-right symmetric
model, by the
WR+WR- channel
and the channel originating
from an anomaly, involving the
SU(2)R gauge group, as well as
decay of such neutrinos. We study the reduction of these neutrinos
for different ranges of left-right model parameters, and find that,
if the neutrino mass exceeds the right-handed gauge boson mass,
then the neutrinos never decouple for realistic values of the
parameters, but, rather, decay in equilibrium. Because
there is no out-of-equilibrium decay, no mass bounds can be set
for the neutrinos.
© Società Italiana di Fisica, Springer-Verlag 2001
