Leptogenesis in crossing and runaway regimes.
Journal article, Peer reviewed
Permanent lenke
http://hdl.handle.net/11250/2374860Utgivelsesdato
2014-07Metadata
Vis full innførselSamlinger
Originalversjon
Hohenegger, A. & Kartavtsev, A. (2014) Leptogenesis in crossing and runaway regimes. Journal of high energy physics 10.1007/JHEP07(2014)130Sammendrag
We study the impact of effective thermal masses and widths on resonant lepto-genesis. We identify two distinct possibilities which we refer to as ‘crossing’ and ‘runaway’ regimes. In the runaway regime the mass difference grows monotonously with temperature, whereas it initially decreases in the crossing regime, such that the effective masses become equal at some temperature. Following the conventional logic the source of the asymmetry would vanish in the latter case. Using non-equilibrium quantum field theory, we analytically demonstrate that the vanishing of the difference of the effective masses does however neither imply a suppression nor a strong enhancement of the source for the lepton asymmetry. In the vicinity of the crossing point the asymmetry calculated in an (improved) Boltzmann limit develops a spurious peak, which signals the breakdown of the quasiparticle approximation. In the exact result this spurious enhancement is compensated by coherent transitions between the two mass shells. Despite the breakdown of the quasiparticle approximation off-shell contributions remain negligibly small even at the crossing point.
Beskrivelse
This is an open access article under the CC BY license, originally published in the journal Higher Energy Physics in 2014.