Portal de Periódicos da CAPES

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

2008; American Physical Society; Volume: 77; Issue: 6 Linguagem: Inglês

10.1103/physrevd.77.063524

1550-7998

Karsten Jedamzik,

Dark Matter and Cosmic Phenomena

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 $^{2}\mathrm{H}$, $^{6}\mathrm{Li}$, and $^{7}\mathrm{Li}$ 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 $^{6}\mathrm{Li}$ and $^{7}\mathrm{Li}$ problems. It is shown that a previously suggested simultaneous solution of the $^{6}\mathrm{Li}$ and $^{7}\mathrm{Li}$ problems for a relic decaying at ${\ensuremath{\tau}}_{x}\ensuremath{\approx}1000\text{ }\text{ }\mathrm{sec}$ is only weakly dependent on the relic being neutral or charged, unless its hadronic branching ratio is small, ${B}_{h}\ensuremath{\ll}{10}^{\ensuremath{-}4}$. 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 $^{6}\mathrm{Li}$ and $^{7}\mathrm{Li}$ problem for long decay times ${\ensuremath{\tau}}_{x}\ensuremath{\gtrsim}{10}^{6}\text{ }\text{ }\mathrm{sec}$ seems possible but fairly unlikely.