Baryogenesis and leptogenesis mechanisms in modified gravity

Determine whether inflationary models based on torsion, non-metricity, or additional scalar/vector sectors in modified gravity—particularly Einstein–Cartan theory and scalar–Gauss–Bonnet couplings—can naturally realize baryogenesis or leptogenesis without ad hoc extensions, and ascertain whether these frameworks can generate sufficient CP violation to explain the matter–antimatter asymmetry.

Background

The review discusses geometric extensions such as Einstein–Cartan theory (torsion) and scalar–Gauss–Bonnet couplings that introduce new interactions and degrees of freedom. Such features could, in principle, furnish out-of-equilibrium dynamics and CP-violating sources needed for baryogenesis or leptogenesis.

Establishing whether these ingredients can replace or complement conventional particle-physics mechanisms is identified as a central, unresolved task.