Primordial nucleosynthesis with non-extensive statistics

Abstract

The conventional Big Bang model successfully anticipates the initial abundances of \(^2\)H(D), \(^3\)He, and \(^4\)He, aligning remarkably well with observational data. However, a persistent challenge arises in the case of \(^7\)Li, where the predicted abundance exceeds observations by a factor of approximately three. Despite numerous efforts employing traditional nuclear physics to address this incongruity over the years, the enigma surrounding the lithium anomaly endures. In this context, we embark on an exploration of Big Bang nucleosynthesis (BBN) of light element abundances with the application of Tsallis non-extensive statistics. A comparison is made between the outcomes obtained by varying the non-extensive parameter q away from its unity value and both observational data and abundance predictions derived from the conventional big bang model. A good agreement is found for the abundances of \(^4\)He, \(^3\)He and \(^7\)Li, implying that the lithium abundance puzzle might be due to a subtle fine-tuning of the physics ingredients used to determine the BBN. However, the deuterium abundance deviates from observations.