Flavour Covariant Formalism for Resonant Leptogenesis
  We present a fully flavour-covariant formalism for transport phenomena and
apply it to study the flavour-dynamics of Resonant Leptogenesis (RL). We show
that this formalism provides a complete and unified description of RL,
consistently accounting for three distinct physical phenomena: (i) resonant
mixing and (ii) coherent oscillations between different heavy-neutrino
flavours, as well as (iii) quantum decoherence effects in the charged-lepton
sector. We describe the necessary emergence of higher-rank tensors in flavour
space, arising from the unitarity cuts of partial self-energies. Finally,
within a Resonant $\tau$-Genesis model, we illustrate the importance of this
formalism by showing that the final lepton asymmetry can vary by as much as an
order of magnitude between partially flavour-dependent treatments, which do not
capture all of the pertinent flavour effects.
