TY - JOUR
T1 - Leptogenesis
T2 - The other cuts
AU - Garbrecht, Björn
N1 - Funding Information:
The author would like to thank Martin Beneke and Pedro Schwaller for useful comments on the manuscript. This work is supported by the Gottfried Wilhelm Leibniz programme of the Deutsche Forschungsgemeinschaft .
PY - 2011/6/11
Y1 - 2011/6/11
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=79952190957&partnerID=8YFLogxK
U2 - 10.1016/j.nuclphysb.2011.01.033
DO - 10.1016/j.nuclphysb.2011.01.033
M3 - Article
AN - SCOPUS:79952190957
SN - 0550-3213
VL - 847
SP - 350
EP - 366
JO - Nuclear Physics, Section B
JF - Nuclear Physics, Section B
IS - 2
ER -