Bridging the primordial A=8 divide with Catalyzed Big Bang Nucleosynthesis

Catalysis of nuclear reactions by metastable charged particles X^- opens the possibility for primordial production of elements with A>7. We calculate the abundance of ^9Be, where synthesis is mediated by the formation of (^8Be X^-) bound states, finding a dramatic enhancement over the standard BBN prediction: ^9Be/^1H = 10^{-13}\times(Y_X/10^{-5}). Thus observations of ^9Be abundances at low metallicity offers a uniquely sensitive probe of many particle physics models that predict X^-, including variants of supersymmetric models. Comparing the catalytically-enhanced abundances of primordial ^6Li and ^9Be, we find the relation ^9Be/^6Li = (2-5)\times 10^{-3} that holds over a wide range of X^- abundances and lifetimes.