Induced gravity inflation in the SU(5) GUT

Abstract

We i n v estigate the cosmological consequences of a theory of induced gravity in which the scalar eld is identied with the Higgs eld of the rst symmetry breaking of a minimal SU(5) GUT. The mass of the X-boson determines a great value for the coupling constant of gravityparticle physics. Because of this fact, a "slow" rollover dynamics for the Higgs eld is not possible in a "new" ination scenario and, moreover, a contraction era for the scale factor in the early universe exists, after which ination follows automatically; "chaotic" ination is performed without problems. Ination is successfully achieved due to the relationship among the masses of particle physics at that scale: The Higgs-, X-boson-and Planck-masses. As a result the particle physics parameter is not ne-tuned as usual in order to predict acceptable values of re-heating temperature and density and gravitational wave perturbations. Moreover, if the coherent Higgs oscillations didn't decay they could explain the missing mass problem of cosmology.

Induced gravity inflation in the standard model of particle physics

“…In this way, the coupling between the Higgs field and gravitation is very strong: the fact that α >> 1 is the price paid in recovering Newton's gravitational constant at that energy scale and it brings some important differences when compared to the standard induced gravity models [18], where to achieve successful inflation typically α << 1 [11,13], and in that way, the existence of a very massive particle (> M P l ) is necessary, which after inflation should decay into gravitons making difficult later an acceptable nucleosynthesis scenario [29].…”

“…The aim of our theory is to obtain GR as a final effect of a symmetry breaking process and in that way to have Newton's gravitational constant G induced by the Higgs field; similar theories have been considered to explain Newton's gravitational constant in the context of a spontaneous symmetrybreaking process to unify gravity with other fields involved in matter interactions, but in much higher energy scales, see Refs. [26,27,28,18].…”

“…Particularly, the cosmological consequences of induced gravity models are well known [10,11,12,13,14,15,16,17], but the particle physics content is still unclear, simply because the Lagrangians used there imply scalar field associated particles with masses greater than the Planck mass (M P l ). Motivated by these requests we have recently studied [18] an induced gravity model of inflation based on a non-minimal coupling between gravity and the SU(5) GUT Higgs field, as an extension to both the minimal SU(5) GUT and Einstein's General Relativity (GR). Now we study, what is the role played by the induced gravity model with a non-minimal coupling in the standard model of particle physics, motivated by some aspects listed below.…”

Induced gravity II: grand unification

“…Induced gravity in models of GUTs have been previously considered, e.g., in ref. [14], but not in the context of renormalizable gravity with dimensional transmutation.…”

MSSM-inspired multifield inflation

“…In numerous models (for a review see [7]) the role of the inflaton has been performed by the Standard Model (SM) Higgs boson [8][9][10][11][12][13][14][15] or a boson in Grand Unified Theories (GUTs) [16,17] or a scalar boson in supersymmetric (SUSY) models [18][19][20] (see [21,22] as reviews). A number of advantages of simplified SUSY GUTs in comparison with nonsupersymmetric GUTs such as naturally longer period of exponential expansion and better stability of the effective Higgs potential with respect to radiative corrections due to cancelation of loop diagrams have been noted quite long ago [23].…”