Gravitino Decays and the Cosmological Lithium Problem in Light of the LHC Higgs and Supersymmetry Searches

Abstract

We studied previously the impact on light-element abundances of gravitinos decaying during or after Big-Bang nucleosynthesis (BBN). We found regions of the gravitino mass m_{3/2} and abundance zeta_{3/2} plane where its decays could reconcile the calculated abundance of Li7 with observation without perturbing the other light-element abundances unacceptably. Here we revisit this issue in light of LHC measurements of the Higgs mass and constraints on supersymmetric model parameters, as well as updates in the astrophysical measurements of light-element abundances. In addition to the constrained minimal supersymmetric extension of the Standard Model with universal soft supersymmetry-breaking masses at the GUT scale (the CMSSM) studied previously, we also study models with universality imposed below the GUT scale and models with non-universal Higgs masses (NUHM1). We calculate the total likelihood function for the light-element abundances, taking into account the observational uncertainties. We find that gravitino decays provide a robust solution to the cosmological Li7 problem along strips in the (m_{3/2}, zeta_{3/2}) plane along which the abundances of deuterium, He4 and Li7 may be fit with chi^2_min < 3, compared with chi^2 ~ 34 if the effects of gravitino decays are unimportant. The minimum of the likelihood function is reduced to chi^2 < 2 when the uncertainty on D/H is relaxed and < 1 when the lithium abundance is taken from globular cluster data.