Revised big bang nucleosynthesis with long-lived, negatively charged massive particles: Updated recombination rates, primordial ⁹be nucleosynthesis, and impact of new ⁶Li limits

We extensively reanalyze the effects of a long-lived, negatively charged massive particle, X ^-, on big bang nucleosynthesis (BBN). The BBN model with an X ^-particle was originally motivated by the discrepancy between the ^{6, 7}Li abundances predicted in the standard BBN model and those inferred from observations of metal-poor stars. In this model, ⁷Be is destroyed via the recombination with an X ^-particle followed by radiative proton capture. We calculate precise rates for the radiative recombinations of ⁷Be, ⁷Li, ⁹Be, and ⁴He with X ^-. In nonresonant rates, we take into account respective partial waves of scattering states and respective bound states. The finite sizes of nuclear charge distributions cause deviations in wave functions from those of point-charge nuclei. For a heavy X ^-mass, m_X≳ 100 GeV, the d-wave → 2P transition is most important for ⁷Li and ^{7, 9}Be, unlike recombination with electrons. Our new nonresonant rate of the ⁷Be recombination for m_X= 1000 GeV is more than six times larger than the existing rate. Moreover, we suggest a new important reaction for ⁹Be production: the recombination of ⁷Li and X ^-followed by deuteron capture. We derive binding energies of X nuclei along with reaction rates and Q values. We then calculate BBN and find that the amount of ⁷Be destruction depends significantly on the charge distribution of ⁷Be. Finally, updated constraints on the initial abundance and the lifetime of the X ^-are derived in the context of revised upper limits to the primordial ⁶Li abundance. Parameter regions for the solution to the ⁷Li problem and the primordial ⁹Be abundances are revised.