Cosmic ⁶Li and ⁷Li problems and BBN with long-lived charged massive particles

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 previously 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 ²H, ⁶Li, and ⁷Li 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 focuses on the impact of CHAMPs on a possible simultaneous solution of the ⁶Li and ⁷Li problems. It is shown that a previously suggested simultaneous solution of the ⁶Li and ⁷Li problems for a relic decaying at τ_x≈1000  sec⁡ is only weakly dependent on the relic being neutral or charged, unless its hadronic branching ratio is small, B_h≪10^-4. 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 ⁶Li and ⁷Li problem for long decay times τ_x≳10⁶  sec⁡ seems possible but fairly unlikely.