Big-Bang Nucleosynthesis Reactions Catalyzed by a Long-Lived Negatively-Charged Leptonic Particle

Accurate quantum three-body calculation is performed for the new rank of big-bang nucleosynthesis (BBN) reactions that are catalyzed by a hypothetical long-lived negativelycharged, massive leptonic particle (called X−) such as a supersymmetric (SUSY) particle stau, the scalar partner of the tau lepton. It is known that if the X− particle has a lifetime of τX >∼ 10 3 s, it would capture a light element previously synthesized in standard BBN and form a Coulombic bound state, for example, (BeX) at temperature T9 <∼ 0.4 (in units of 10 K), (αX−) at T9 <∼ 0.1 and (pX −) at T9 <∼ 0.01. The bound state, an exotic atom, is expected to induce the following reactions in which X− works as a catalyzer: i) α-transfer reactions such as (αX−)+d → Li+X, ii) radiative capture reactions such as (BeX)+p → (BX) + γ, iii) three-body breakup reactions such as (LiX) + p → α + α + X−, iv) charge-exchange reactions such as (pX−)+α → (αX−)+p, and v) neutron induced reactions such as (BeX) + n → Be + X−. Recent literature papers have claimed that some of these X−-catalyzed reactions have significantly large cross sections so that inclusion of the reactions into the BBN network calculation can change drastically abundances of some elements, giving not only a solution to the Li-Li problem (calculated underproduction of Li by ∼ 1000 times and overproduction of Li+Be by ∼ 3 times) but also a constraint on the lifetime and the primordial abundance of the elementary particle X−. However, most of these literature calculations of the reaction cross sections were made assuming too naive models or approximations that are unsuitable for those complicated low-energy nuclear reactions. We use a high-accuracy few-body calculational method developed by the authors, and provides precise cross sections and rates of those catalyzed BBN reactions for the use in the BBN network calculation.