Big-bang nucleosynthesis reactions catalyzed by a long-lived negatively charged leptonic particle

An accurate quantum three-body calculation is performed for 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 stati, the scalar partner of the tau lepton. It is known that if the X^- particle has a lifetime TX ≥ 10³ s, it can capture a light element previously synthesized in standard BBN and form a Coulombic bound state, for example, ( ⁷BeX^- at temperature T⁹ ≤ 0.4 (in units of 10⁹ 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^- acts as a catalyst: i) α-transfer reactions such as (αX^-)+ d → ⁶Li +X, ii) radiative capture reactions such as ( ⁷BeX^-) +p → (⁸BX^-+ γ, iii) three-body breakup reactions such as (pX^-) + α → α + α + X^-, iv) charge-exchange reactions such as (pX^-) + α → (aX^-) + p and v) neutron induced reactions such as (⁸BeX^- + n → ⁹Be + X^- In recent papers it has been claimed that some of these X ^- catalyzed reactions have significantly large cross sections so that the inclusion of the reactions into the BBN network calculation can markedly change the abundances of some elements, giving not only a solution to the ⁶Li-⁷Li problem (the calculated underproduction of ⁶Li by a factor of ̃ 1000 and overproduction of ⁷Li+⁷Be by a factor of ̃ 3) but also a constraint on the lifetime and primordial abundance of the elementary particle X. However, most of these calculations of the reaction cross sections in the literature were performed assuming too naive models or approximations that are unsuitable for these complicated low-energy nuclear reactions. We use a high-accuracy few-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.