Seminars

Unifying inflation with the axion, dark matter, baryogenesis and the seesaw mechanism

by Carlos Tamarit (IPPP Durham)

Thursday, 18 May 2017 from to (Europe/Vienna)
at HEPHY ( Library )
Description
A minimal extension of the standard model (SM) with a single new mass scale and providing a complete and consistent picture of particle physics and cosmology up to the Planck scale is presented. We add to the SM three right-handed SM-singlet neutrinos, a new vectorlike color triplet fermion, and a complex SM-singlet scalar σ that stabilizes the Higgs potential and whose vacuum expectation value at ∼1011  GeV breaks lepton number and a Peccei-Quinn symmetry simultaneously. Primordial inflation is produced by a combination of σ (nonminimally coupled to the scalar curvature) and the SM Higgs boson. Baryogenesis proceeds via thermal leptogenesis. At low energies, the model reduces to the SM, augmented by seesaw-generated neutrino masses, plus the axion, which solves the strong CP problem and accounts for the dark matter in the Universe. The model predicts a minimum value of the tensor-to-scalar ratio r≃0.004, running of the scalar spectral index α≃-7×10-4, the axion mass mA∼100  μeV, and cosmic axion background radiation corresponding to an increase of the effective number of relativistic neutrinos of ∼0.03. It can be probed decisively by the next generation of cosmic microwave background and axion dark matter experiments.