A minimal model of inflation and dark radiation

  • Data: 19 settembre 2019

  • Luogo: Aula Teorici, piano 2, via Irnerio 46, Bologna

Contatto di riferimento:

Partecipanti: Dr. Antonio Racioppi: National Institute of Chemical Physics and Biophysics, Tallinn, Estonia

Abstract: We show that a minimal extension of the Standard Model including a new complex scalar field can explain inflation and the observed effective number of neutrinos. The real part of the singlet plays the rôle of the inflaton field, while the Goldstone boson emerging from the spontaneous symmetry breaking of a global U(1) symmetry contributes to dark radiation and increases the effective number of neutrino species by 0.3 over the Standard Model value. After detailing the phenomenology of the model, we find that the predicted inflationary observables are in agreement with the current bounds, once the dark radiation component is allowed, both within the metric and Palatini formulation of non-minimally coupled gravity.