  The Type II Seesaw Mechanism provides a minimal framework to explain the
neutrino masses involving the introduction of a single triplet Higgs to the
Standard Model. However, this simple extension was believed to be unable to
successfully explain the observed baryon asymmetry of the universe through
Leptogenesis. In our previous work (Phys. Rev. Lett. 128, 141801), we
demonstrated that the triplet Higgs of the Type II Seesaw Mechanism alone can
simultaneously generate the observed baryon asymmetry of the universe and the
neutrino masses while playing a role in setting up Inflation. This is
achievable with a triplet Higgs mass as low as 1 TeV, and predicts that the
neutral component obtains a small vacuum expectation value $v_\Delta < 10 $
keV. We find that our model has very rich phenomenology and can be tested by
various terrestrial experiments as well as by astronomical observations.
Particularly, we show that the successful parameter region may be probed at a
future 100 TeV collider, upcoming lepton flavor violation experiments such as
Mu3e, and neutrinoless double beta decay experiments. Additionally, the
tensor-to-scalar ratio from the inflationary scenario will be probed by the
LiteBIRD telescope, and observable isocurvature perturbations may be produced
for some parameter choices. In this article, we present all the technical
details of our calculations and further discussion of its phenomenological
implications.
