Phenomenology of the minimal inflation scenario: inflationary trajectories and particle production

TL;DR

This paper explores a minimal inflation model focusing on inflationary trajectories and particle production, proposing natural flat trajectories, a new particle generation mechanism, and predictions for gravitino mass and gravitational wave levels.

Contribution

It introduces a formalism for identifying attractors in multi-field inflation and presents a novel particle production mechanism involving goldstinos, with implications for dark matter and observable gravitational waves.

Findings

Inflationary trajectories are naturally flat without fine-tuning.

A new mechanism for particle and entropy generation via goldstino sea filling.

Predicted gravitational wave levels are within detectable range of upcoming experiments.

Abstract

We discuss the phenomenology of the minimal inflation scenario. We concentrate on two aspects: inflationary trajectories and particle production. Our findings can be summarized in two main results: first, that inflationary trayectories that are very flat and provide enough number of e-foldings are natural in the scenario without fine tunning. We present a general formalism to identify attractors in multi-field inflation regardless of trajectories fulfilling the slow-roll conditions. We then explore particle production in the model and show how the inflaton naturally transmutes into a dark matter particle. One interesting feature of our model is that it provides a novel mechanism to generate particles and entropy in the universe: the filling of the Fermi sphere up to a given momentum p_F due to the sea of goldstinos that are an important part of the matter generated after inflation. With this mechanism in hand we predict that the gravitino should have a mass of > 100-1000 TeV. Another interesting feature of our model is that the predicted level of gravity waves is r=0.1 - 0.001, which is in the range of detectability from Planck and upcoming CMB polarization experiments.