Seminar of department “Theory of Fundamental Interactions”

Date and Time: Thursday, 24 May 2018, at 4:00 PM

Venue: Blokhintsev Hall (4th floor), Bogoliubov Laboratory of Theoretical Physics

Seminar topic: «Quick fix to Higgs metastability»

Speaker: C.R. Das

Abstract:

Five fundamental problems – neutrino oscillations, baryogenesis, dark matter, inflation, strong CP problem – are solved at one stroke in a model, dubbed as “SM-A-S-H” (Standard Model-Axion-Seesaw-Higgs portal inflation) by Andreas Ringwald et. al. A minimal extension of the Standard Model (SM) presented with a single new mass scale and providing a complete and consistent picture of particle physics from the electro-weak scale up to the Planck scale, and of cosmology from inflation until today. The Standard Model (SM) particle content is extended by three right-handed SM-singlet neutrinos Ni, a vector-like color triplet quark Q, a complex SM-singlet scalar field σ that stabilises the Higgs potential, all of them being charged under a global lepton number (hyper-charge) and Peccei-Quinn (PQ) U(1) symmetry, the vacuum expectation value υ_σ ~ 10¹¹ GeV breaks the lepton number and the Peccei-Quinn symmetry simultaneously. Primordial inflation is produced by a combination of σ (non-minimally coupled to the scalar curvature) and the SM Higgs. At low energies, the model reduces to the SM, augmented by seesaw generated neutrino masses and mixing, plus the axion, which solves the strong CP problem and accounts for the cold dark matter in the Universe. The inflaton is comprised by a mixture of σ and the SM Higgs, and reheating of the Universe after inflation proceeds via the Higgs portal. Baryogenesis occurs via thermal leptogenesis.

Recently we found out numerically that, this SMASH model not only solves five fundamental problems but also the sixth problem “Vacuum Metastability” through the extended scalar sector.

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