Probing Leptogenesis at Future Colliders
  We investigate the question whether leptogenesis, as a mechanism for
explaining the baryon asymmetry of the universe, can be tested at future
colliders. Focusing on the minimal scenario of two right-handed neutrinos, we
identify the allowed parameter space for successful leptogenesis in the heavy
neutrino mass range between $5$ and $50$ GeV. Our calculation includes the
lepton flavour violating contribution from heavy neutrino oscillations as well
as the lepton number violating contribution from Higgs decays to the baryon
asymmetry of the universe. We confront this parameter space region with the
discovery potential for heavy neutrinos at future lepton colliders, which can
be very sensitive in this mass range via displaced vertex searches. Beyond the
discovery of heavy neutrinos, we study the precision at which the
flavour-dependent active-sterile mixing angles can be measured. The measurement
of these mixing angles at future colliders can test whether a minimal type I
seesaw mechanism is the origin of the light neutrino masses, and it can be a
first step towards probing leptogenesis as the mechanism of baryogenesis. We
discuss how a stronger test could be achieved with an additional measurement of
the heavy neutrino mass difference.
