BBN implications from a GeV-scale metastable sector

by Josef Pradler (Perimeter Institute)

Wednesday 23 Jun 2010, 14:15 → 15:15 Europe/Berlin

Auditorium (MPI fuer Physik)

The persistent discrepancy between observations of lithium with putative primordial origin and its abundance prediction in Big Bang Nucleosynthesis (BBN) has become a challenge for the standard cosmological and astrophysical picture. We point out that the decay of GeV-scale metastable particles X may significantly reduce the BBN value down to a level at which it is reconciled with observations. The most efficient reduction occurs when the decay happens to charged pions and kaons, followed by their charge exchange reactions with protons. Similarly, if X decays to muons, secondary electron anti-neutrinos produce a similar effect. We consider the viability of these mechanisms in different classes of new GeV-scale sectors, and find that several minimal extensions of the Standard Model with metastable vector and/or scalar particles are capable of solving the cosmological lithium problem. Such light states can be searched in a variety of high-intensity medium-energy experiments.