# Geometrical destabilization, premature end of inflation and Bayesian model selection

## TL;DR

This paper uses Bayesian methods to analyze how geometrical destabilization causing premature inflation end impacts observational evidence and model rankings, significantly altering parameter constraints and interpretations of cosmological data.

## Contribution

It introduces a Bayesian framework to assess the effects of geometrical destabilization on inflationary models and their observational viability.

## Key findings

- Large field models are worsened by premature end effects.
- Inflection point potentials are significantly improved within certain curvature ranges.
- Model rankings and parameter constraints are substantially altered by premature inflation termination.

## Abstract

By means of Bayesian techniques, we study how a premature ending of inflation, motivated by geometrical destabilization, affects the observational evidences of typical inflationary models. Large field models are worsened, and inflection point potentials are drastically improved for a specific range of the field-space curvature characterizing the geometrical destabilization. For other models we observe shifts in the preferred values of the model parameters. For quartic hilltop models for instance, contrary to the standard case, we find preference for theoretically natural sub-Planckian hill widths. Eventually, the Bayesian ranking of models becomes substantially reordered with a premature end of inflation. Such a phenomenon also modifies the constraints on the reheating expansion history, which has to be properly accounted for since it determines the position of the observational window with respect to the end of inflation. Our results demonstrate how the interpretation of cosmological data in terms of fundamental physics is considerably modified in the presence of premature end of inflation mechanisms.