Spontaneous B-L Breaking as the Origin of the Hot Early Universe

TL;DR

This paper explores how spontaneous B-L symmetry breaking from a false vacuum can initiate the hot early universe, linking inflation, leptogenesis, and dark matter production within a supersymmetric framework.

Contribution

It provides a detailed analysis of the phase transition, reheating dynamics, and the resulting particle abundances, establishing connections between neutrino parameters and superparticle masses.

Findings

Hybrid inflation ends with tachyonic preheating.

Heavy neutrino decays produce entropy, baryon asymmetry, and dark matter.

Lower bound on gravitino mass is 10 GeV for 1 TeV gluino.

Abstract

The decay of a false vacuum of unbroken B-L symmetry is an intriguing and testable mechanism to generate the initial conditions of the hot early universe. If B-L is broken at the grand unification scale, the false vacuum phase yields hybrid inflation, ending in tachyonic preheating. The dynamics of the B-L breaking Higgs field and thermal processes produce an abundance of heavy neutrinos whose decays generate entropy, baryon asymmetry and gravitino dark matter. We study the phase transition for the full supersymmetric Abelian Higgs model. For the subsequent reheating process we give a detailed time-resolved description of all particle abundances. The competition of cosmic expansion and entropy production leads to an intermediate period of constant 'reheating' temperature, during which baryon asymmetry and dark matter are produced. Consistency of hybrid inflation, leptogenesis and gravitino dark matter implies relations between neutrino parameters and superparticle masses. In particular, for a gluino mass of 1 TeV, we find a lower bound on the gravitino mass of 10 GeV.