Destruction of 7Be in big bang nucleosynthesis via long-lived sub-strongly interacting massive particles as a solution to the Li problem

TL;DR

This paper explores how long-lived sub-strongly interacting particles could catalyze the destruction of 7Be during big bang nucleosynthesis, potentially resolving the lithium problem by adjusting nuclear reaction pathways.

Contribution

It proposes a novel mechanism involving sub-SIMP particles to selectively destroy 7Be without affecting other nuclei, offering a new solution to the lithium problem in cosmology.

Findings

Identifies key reactions for 7Be destruction via sub-SIMP catalysis.

Suggests interaction strength conditions for effective 7Be destruction.

Highlights the need for rigorous quantum mechanical calculations for validation.

Abstract

We identify reactions which destroy 7Be and 7Li during big bang nucleosynthesis (BBN) in the scenario of BBN catalyzed by a long-lived sub-strongly interacting massive particle (sub-SIMP or X particle). The destruction associated with non radiative X captures of the nuclei can be realized only if the interaction strength between an X particle and a nucleon is properly weaker than that between two nucleons to a degree depending on the mass of X. Binding energies of nuclei to an X particle are estimated taking the mass and the interaction strength to nuclei of the X as input parameters. Nuclear reaction rates associated with the X are estimated naively, and adopted in calculating evolutions of nuclear abundances. We suggest that the 7Li problem, which might be associated with as-yet-unrecognized particle processes operating during BBN, can be solved if the X particle interacts with nuclei strongly enough to drive 7Be destruction but not strongly enough to form a bound state with 4He of relative angular momentum L=1. Justifications of this scenario by rigorous calculations of reaction rates using quantum mechanical many-body models are highly desirable since this result involves many significant uncertainties.