Leptogenesis: The Other Cuts
arXiv:1011.3122 · doi:10.1016/j.nuclphysb.2011.01.033
Abstract
For standard leptogenesis from the decay of singlet right-handed neutrinos, we derive source terms for the lepton asymmetry that are present in a finite density background but absent in the vacuum. These arise from cuts through the vertex correction to the decay asymmetry, where in the loop either the Higgs boson and the right-handed neutrino or the left-handed lepton and the right-handed neutrino are simultaneously on shell. We evaluate the source terms numerically and use them to calculate the lepton asymmetry for illustrative points in parameter space, where we consider only two right-handed neutrinos for simplicity. Compared to calculations where only the standard cut through the propagators of left-handed lepton and Higgs boson is included, sizable corrections arise when the masses of the right-handed neutrinos are of the same order, but the new sources are found to be most relevant when the decaying right-handed neutrino is heavier than the one in the loop. In that situation, they can yield the dominant contribution to the lepton asymmetry.
22 pages, 4 figures
References in corpus (5)
- Quantum Boltzmann Equations and Leptogenesis
- The importance of N2 leptogenesis
- The problem of the initial conditions in flavoured leptogenesis and the tauon N_2-dominated scenario
- Quantum corrections to leptogenesis from the gradient expansion
- CP Violation from Scatterings with Gauge Bosons in Leptogenesis