Late time acceleration in a slow moving galileon field

TL;DR

This paper investigates a slow moving galileon field with a potential as a model for late-time cosmic acceleration, analyzing its dynamics, perturbations, and observational constraints to establish its viability.

Contribution

It introduces a ghost-free galileon model with a potential that can produce late-time acceleration and explores its cosmological implications and observational constraints.

Findings

The model can produce viable late-time acceleration without ghosts.

Different BBN constraints are observed at early times.

Observational data constrains the model parameters effectively.

Abstract

In this paper, we examine the cosmological viability of a slow moving galileon field in a potential. The Lagrangian $\cal{L}$ $ =-\frac{1}{2}g^{\mu\nu}\pi_{;\mu}\pi_{;\nu} +\frac{G^{\mu\nu}}{2M^2}\pi_{;\mu}\pi_{;\nu}$ respects the galileon symmetry in curved space time. We carry out detailed investigations of the underlying dynamics of this Lagrangian with Einstein-Hilbert term and a potential. We demonstrate that the model can give rise to a viable ghost free late time acceleration of universe. Furthermore we study the cosmological perturbation of the model and see that the model gives different BBN constraints at early times. We also carry out the observational analysis of the model and use observational data from growth, Type Ia Supernovae (SNIa), Baryon Acoustic Oscillations (BAO) and Cosmic Microwave Background (CMB) to constrain the parameters of the theory.