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

TL;DR

This paper performs precise quantum three-body calculations to evaluate the cross sections of big-bang nucleosynthesis reactions catalyzed by a long-lived negatively charged particle, addressing previous inaccuracies and implications for element abundances.

Contribution

The authors introduce a high-accuracy few-body computational method to accurately determine reaction cross sections for catalyzed BBN processes involving a long-lived charged particle.

Findings

Provided precise cross sections and reaction rates for catalyzed BBN reactions.

Challenged previous estimates by using more accurate few-body calculations.

Implications for element abundance predictions and constraints on new particles.

Abstract

An accurate quantum three-body calculation is performed for the new type of big-bang nucleosynthesis (BBN) reactions that are catalyzed by a long-lived negatively-charged, massive leptonic particle (called X^-) such as the supersymmetric (SUSY) particle stau. The reactions studied here includes, i) 4He-transfer reactions such as (4He X)+d --> 6Li+X, ii) radiative capture reactions such as (7Be X)+ p --> (8B X) + gamma, iii) three-body breakup reactions such as (7Li X)+ p --> 4He+4He+X, iv) charge-exchange reactions such as (p X)+4He -->(4He X) +p, and v) neutron induced reactions such as (8Be X)+ n -->9Be+X, where (A X) denotes a Coulombic bound state of a nucleus A and X^-. In recent papers it has been claimed that some of the catalyzed BBN reactions have significantly large cross sections so as to markedly change the abundances of some elements, not only giving a solution to the 6Li-7Li problem (calculated underproduction of 6Li by a factor of 1000 and overproduction of 7Li+7Be by a factor of nearly 3) but also imposing strong restrictions on the lifetime and the primordial abundance of X^-. However, most of the calculations of these reaction cross sections in the literature were performed assuming too naive models or approximations that are unsuitable for the complicated low-energy nuclear reactions. We use a high-accuracy few-body calculational method developed by the authors, and provide precise cross sections and rates of these catalyzed BBN reactions for use in the BBN network calculation.