Big Bang Nucleosynthesis of $^6$Li and $^7$Li*

The $^6$Li abundance observed in metal poor halo stars exhibits a plateau similar to that for $^7$Li suggesting a primordial origin. However, the observed abundance of $^6$Li is a factor of $10^3$ larger and that of $^7$Li is a factor of 3 lower than the abundances predicted in the standard big bang when the baryon-to-photon ratio is fixed by WMAP. Here we show that both of these abundance anomalies can be explained by the existence of a long-lived massive, negatively-charged leptonic particle during nucleosynthesis. Such particles would capture onto the newly synthesized nuclei thereby reducing the reaction Coulomb barriers and opening new transfer reaction possibilities, which catalyze a second round of big bang nucleosynthesis. This novel solution to both of the Li problems can be achieved with or without the additional effects of stellar destruction.