Stau-catalyzed big-bang nucleosynthesis reactions

We study the new type of big-bang nucleosynthesis (BBN) reactions that are catalyzed by a hypothetical long-lived negatively charged, massive leptonic particle (called X^-) such as the supersymmetric(SUSY) particle stau, the scalar partner of the tau lepton. It is known that if the X^- particle has a lifetime of τ_X ≳ 10³ s, it can capture a light element previously synthesized in standard BBN and form a Coulombic bound state and induces various types of reactions in which X ^- acts as a catalyst. Some of these X^- -catalyzed reactions have significantly large cross sections so that the inclusion of there actions into the BBN network calculation can markedly change the abundances of some elements. We use a high-accuracy three-body calculation method developed by the authors and provide precise cross sections and rates of these catalyzed BBN reactions for use in the BBN network calculation.