Metastable GeV-scale particles as a solution to the cosmological lithium problem

Understand

The persistent discrepancy between observations of 7Li 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 antineutrinos produce a similar effect.