Speaker
Description
We consider the dynamics of the standard model extended by two or more right
handed neutrinos, which simultaneously explains the origin of neutrino masses
through the seesaw mechanism and the baryon asymmetry of the universe
through leptogenesis.
Specifically, we focus on right handed neutrinos with GeV scale mass which can
be found in collider or fixed target experiments.
We use quantum kinetic equations to calculate the baryon asymmetry produced
through right-handed neutrino oscillations in the early universe, and predict
their properties from the requirement to explain the observed baryon asymmetry
of the universe.
By identifying the time scales of oscillations and equilibration, and
comparing them we find two regimes of production.
The oscillatory regime, where the oscillations happen much earlier than the equilibration of the right handed neutrinos, which is suitable for calculating
the baryon asymmetry for regions of parameter space where the mixing between
the left- and right-handed neutrinos is small.
For large mixing angles we find the overdamped regime,
where one of the right handed neutrinos typically reaches equilibrium before
the oscillations among the right handed neutrinos begin.
We develop analytic approximations for each of the two regimes, and use them
to derive predictions of the right handed neutrino properties if they are
responsible for the origin of matter.
