Updated Big Bang Nucleosynthesis Bounds on Long-lived Particles from Dark Sectors

TL;DR

This paper refines constraints on long-lived particles from dark sectors by analyzing their electromagnetic energy injection effects on primordial element abundances, using updated cosmological measurements.

Contribution

It provides new bounds on electromagnetic energy injection from long-lived particles based on recent light element abundance data and CMB measurements.

Findings

Stronger limits on electromagnetic energy injection from long-lived particles.

Constraints applicable to dark matter decay, gravitinos, and early universe non-thermal processes.

Bounds cover particles decaying between 10^2 and 10^{10} seconds.

Abstract

As electromagnetic showers may alter the abundance of Helium, Lithium, and Deuterium, we can place severe constraints on the lifetime and amount of electromagnetic energy injected by long-lived particles. Considering up-to-date measurements of the light element abundances that point to $Y_p=0.245\pm 0.003$, $({\rm D/H})= (2.527\pm 0.03)\times 10^{-5}$, and the baryon-to-photon ratio obtained from the Cosmic Microwave Background data, $\eta=6.104 \times 10^{-10}$, we derive upper limits on the fraction of electromagnetic energy produced by long-lived particles. Our findings apply to decaying dark matter models, long-lived gravitinos, and other non-thermal processes that occurred in the early universe between $10^2-10^{10}$ seconds.