Big Bang Nucleosynthesis with Long Lived Charged Massive Particles

Abstract

We consider Big Bang Nucleosynthesis (BBN) with long lived charged massive particles. Before decaying, the long lived charged particle recombines with a light element to form a bound state like a hydrogen atom. This effect modifies the nuclear reaction rates during the BBN epoch through the modifications of the Coulomb field and the kinematics of the captured light elements, which can change the light element abundances. It is possible that the heavier nuclei abundances such as $^7$Li and $^7$Be decrease sizably, while the ratios $Y_p$, D/H, and $^3$He/H remain unchanged. This may solve the current discrepancy between the BBN prediction and the observed abundance of $^7$Li. If future collider experiments found signals of a long-lived charged particle inside the detector, the information of its lifetime and decay properties could provide insights to understand not only the particle physics models but also the phenomena in the early universe in turn.