Constraining the Lorentz-violating bumblebee vector field with big bang nucleosynthesis and gravitational baryogenesis

Mohsen Khodadi; Gaetano Lambiase; Ahmad Sheykhi

doi:10.1140/epjc/s10052-023-11546-3

2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2023) 83: 386
https://doi.org/10.1140/epjc/s10052-023-11546-3

Regular Article - Theoretical Physics

Constraining the Lorentz-violating bumblebee vector field with big bang nucleosynthesis and gravitational baryogenesis

Mohsen Khodadi¹^,2, Gaetano Lambiase³^,4^b and Ahmad Sheykhi¹^,2

¹ Department of Physics, College of Sciences, Shiraz University, 71454, Shiraz, Iran
² Biruni Observatory, College of Sciences, Shiraz University, 71454, Shiraz, Iran
³ Dipartimento di Fisica “E.R Caianiello”, Università degli Studi di Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano (SA), Italy
⁴ Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Salerno, Sezione di Napoli, Via Giovanni Paolo II, 132, 84084, Fisciano (SA), Italy

^b lambiase@sa.infn.it

Received: 19 January 2023
Accepted: 23 April 2023
Published online: 10 May 2023

Abstract

By assuming the cosmological principle i.e., an isotropic and homogeneous universe, we consider the cosmology of a vector-tensor theory of gravitation known as the bumblebee model. In this model a single Lorentz-violating timelike vector field with a nonzero vacuum expectation value (VEV) couples to the Ricci tensor and scalar, as well. Taking the ansatz $B (t) \sim t^{β}$ $B(t)\sim t^\beta$ for the time evolution of the vector field, where $β$ $\beta$ is a free parameter, we derive the relevant dynamic equations of the Universe. In particular, by employing observational data coming from the Big Bang Nucleosynthesis (BBN) and the matter–antimatter asymmetry in the baryogenesis era, we impose some constraints on the VEV of the bumblebee timelike vector field i.e., $ξ b^{2}$ $\xi b^2$ , and the exponent parameter $β$ $\beta$ . The former and the latter limit the size of Lorentz violation, and the rate of the time evolution of the background Lorentz-violating bumblebee field, respectively.

© The Author(s) 2023

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