Primordial Cosmological Inflation and the Higgs Boson

Abstract

Primordial Inflation is thought to be the stage of quasi exponential expansion of the Universe which gives rise to a large, almost homogenous and flat metric, with the correct initial conditions for the radiation dominated era from which the Universe has evolved about 13 billion years ago. Such a mechanism requires a scalar field to dominate the energy density of the Universe and to produce small fluctuations which later develop into structures and galaxies. For a narrow band of values of the top quark and Higgs boson masses, the Standard Model Higgs field can develop a second minimum in its potential at energies of about 1015 – 1016 GeV and therefore we propose that the Higgs field can be a possible source of primordial Inflation, provided that a successful transition from Inflation to a radiation dominated era can be achieved. I will present two possible mechanisms which realize this idea: by adding a Brans-Dicke scalar to gravity or by introducing a hybrid model with a new scalar very weakly coupled to the Higgs. We have predicted this to happen only for a narrow window of values for the Higgs mass, of about (126 ± 3) GeV, which has been later confirmed by the LHC discovery at 126 GeV. We discuss features of the models and point out that they can be further checked with: more precise measurements of the top quark mass and by cosmological observables (especially the tensor-to-scalar ratio).

Data: 13 de fevereiro

Hora: 11 h (será servido café às 10:30 h)

Local: Instituto de Física - Sala 343-A

Alessio Notari

Departament de Física Fondamental i Institut de Ciéncies del Cosmos

Universitat de Barcelona