Electroweak baryogenesis by primordial black holes in Brans-Dicke modified gravity

Abstract

A successful baryogenesis mechanism is proposed in the cosmological framework of Brans-Dicke modified gravity. Primordial black holes with small mass are produced at the end of the Brans-Dicke field domination era. The Hawking radiation reheats a spherical region around every black hole to a high temperature and the electroweak symmetry is restored there. A domain wall is formed separating the region with the symmetric vacuum from the asymmetric region where electroweak baryogenesis takes place. First order phase transition is not needed. In Brans-Dicke cosmologies black hole accretion can be strong enough to lead to black holes domination which extends the lifetime of black holes and therefore baryogenesis. The analysis of the whole scenario, finally, results in the observed baryon number which can be achieved for a CP-violation angle that is predicted by observationally accepted Two-Higgs Doublet Models. The advantage of our proposed scenario is that naturally provides both black hole domination and more efficient baryogenesis for smaller CP violating angles compared to the same mechanism applied in a FRW cosmological background.

Dark sector production and baryogenesis from not quite black holes *

“…This usually indicates the modification of the Higgs potential, and a large deviation of the Higgs self-interactions, which serve as an important target for the future collider. New physics models that incorporate both ingredients have been extensively studied to realize baryogenesis [129][130][131].…”

Formation and clustering of primordial black holes in Brans-Dicke theory

“…The paper [21] considered the effect of the gravitational constant changes in the Brans-Dicke theory on the number of PBHs formed. The evolution of PBHs population in the Brans-Dicke cosmology was also studied in [22,23]. A PBH is formed only from density perturbation that is greater than certain threshold value.…”

“…In this paper, we also calculate corrections to the threshold of PBHs formation, but we do it within the framework of the Brans-Dicke theory. In contrast to [21][22][23], we write down equations for the evolution of spherical-symmetric perturbations in the Brans-Dicke theory and consider the gravitational collapse. The corrections depend on the scalar field of the Brans-Dicke theory.…”