Theoretical and observational constraints on Tachyon Inflation

TL;DR

This paper evaluates various Tachyon Inflation models using theoretical constraints and recent observational data, identifying which models are favored or disfavored based on Bayesian analysis and field range considerations.

Contribution

It introduces a comprehensive analysis of multiple Tachyon Inflation models, combining theoretical field excursion limits with observational data to assess their viability.

Findings

Original potential V ∝ sech(T) is strongly disfavoured by data.

Polynomial and perturbative potentials are statistically favored.

Some models require large field ranges, possibly needing quantum corrections.

Abstract

We constrain several models in Tachyonic Inflation derived from the large-$N$ formalism by considering theoretical aspects as well as the latest observational data. On the theoretical side, we assess the field range of our models by means of the excursion of the equivalent canonical field. On the observational side, we employ BK14+PLANCK+BAO data to perform a parameter estimation analysis as well as a Bayesian model selection to distinguish the most favoured models among all four classes here presented. We observe that the original potential $V \propto \textrm{sech}(T)$ is strongly disfavoured by observations with respect to a reference model with flat priors on inflationary observables. This realisation of Tachyon inflation also presents a large field range which may demand further quantum corrections. We also provide examples of potentials derived from the polynomial and the perturbative classes which are both statistically favoured and theoretically acceptable.