Leptogenesis is a very attractive scenario that ties the generation of
the matter-antimatter asymmetry in our universe to the tiny observed
neutrino masses from the Seesaw mechanism.
We review the basic picture and recent developments in the field with a
focus on right handed neutrino (RHN) masses far above the electroweak
Gravitational wave astronomy is a novel way to probe both the Seesaw and
the Leptogenesis scale, which are completely inaccessible to laboratory
experiments in these high scale scenarios.
We discuss the damping of inflationary gravitational waves (GW) that
reenter the horizon before or during an epoch, where the energy budget
of the universe is dominated by an unstable right handed neutrino, whose
out of equilibrium decay releases entropy.
Starting from the minimal Standard Model extension with nothing more
than 3 RHN for the Seesaw mechanism, we discuss the conditions for high
scale Leptogenesis assuming a thermal initial population of RHN.
One of our main findings is that the frequency, above which the damping
of the tensor modes is potentially observable, is completely determined
by successful Leptogenesis and a Davidson-Ibarra type bound to be at
around 0.1 Hz.
To quantify the detection prospects of this GW background for various
proposed interferometers such asAEDGE,BBO, DECIGO,Einstein
TelescopeorLISAwe compute thesignal-to-noise ratio(SNR).
Andrea Pelloni, Tanjona Rabemananjara, Tommaso Giani