Instant preheating in a scale invariant two measures theory

TL;DR

This paper explores instant preheating within a scale invariant two measures theory, introducing a novel mechanism for universe reheating involving scalar fields and their interactions, with derived decay rates and parameter constraints.

Contribution

It presents a new implementation of instant preheating in a scale invariant two measures framework, including detailed decay rate calculations and parameter bounds.

Findings

Derived decay rates for scalar field interactions with fermions.

Established constraints on coupling parameters in the model.

Proposed a viable reheating mechanism in a non oscillating inflationary scenario.

Abstract

The instant preheating mechanism in the framework of a scale invariant two measures theory is studied. We introduce this mechanism into a non oscillating inflationary model as another possible solution to the reheating of the universe in this theory. In this framework, we consider that the model includes two scalar matter fields, the first a dilaton field, that transforms under scale transformations and it will be considered also as the field that drives inflation and the second, a scalar field which will interact with the inflaton through an effective potential. By assuming this interaction term, we obtain a scenario of instant radiation or decay of particles according to the domain the effective mass of the field that interacts with the inflaton. Also, we consider a scale invariant Yukawa interaction and then after performing the transition to the physical Einstein frame we obtain an expression for the decay rate from our scalar field going into two fermions. Besides, from specific decay rates, different constraints and bounds for the coupling parameters associated with our model are found.