Cosmic $^6$Li and $^7$Li problems and BBN with long-lived charged massive particles
Karsten Jedamzik

Charged massive particles (CHAMPs), when present during the Big Bang nucleosynthesis (BBN) era, may significantly alter the synthesis of light elements when compared to a standard BBN scenario. This is due to the formation of bound states with nuclei. This paper presents a detailed numerical and analytical analysis of such CHAMP BBN. All reactions important for predicting light-element yields are calculated within the Born approximation. Three priorly neglected effects are treated in detail:(a) photodestruction of bound states due to electromagnetic cascades induced by the CHAMP decay, (b) late-time efficient destruction/production of\h2, \li6, and \li7 due to reactions on charge $Z=1$ nuclei bound to CHAMPs, and (c) CHAMP exchange between nuclei. Each of these effects may induce orders-of-magnitude changes in the final abundance yields. The study focusses on the impact of CHAMPs on a possible simultaneous solution of the \li6 and \li7 problems. It is shown that a priorly suggested simultaneous solution of the \li6 and \li7 problems for a relic decaying at $\tau_x\approx 1000\,$sec is only very weakly dependent on the relic being neutral or charged, unless its hadronic branching ratio is $B_h\ll 10^{-4}$ very small. By use of a Monte-Carlo analysis it is shown that within CHAMP BBN the existence of further parameter space for a simultaneous solution of the \li6 and \li7 problem for long decay times $\tau_x\simge 10^6$sec seems possible but fairly unlikley.

© 2008 The American Physical Society.