TY - JOUR
T1 - Scattering rates for leptogenesis
T2 - Damping of lepton flavour coherence and production of singlet neutrinos
AU - Garbrecht, Björn
AU - Glowna, Frank
AU - Schwaller, Pedro
N1 - Funding Information:
We thank M. Beneke for discussions and collaboration in early stages of this project. Research of P.S. was supported by the U.S. Department of Energy, Division of High Energy Physics , under contracts DE-AC02-06CH11357 and DE-FG02-12ER41811 . B.G. and F.G. acknowledge support by the Gottfried Wilhelm Leibniz programme of the DFG , and by the DFG cluster of excellence ‘Origin and Structure of the Universe’ .
PY - 2013/12/1
Y1 - 2013/12/1
N2 - Using the Closed Time Path (CTP) approach, we perform a systematic leading order calculation of the relaxation rate of flavour correlations of left-handed Standard Model leptons. This quantity is of pivotal relevance for flavoured leptogenesis in the Early Universe, and we find it to be 5.19×10-3T at T=107 GeV and 4.83×10-3T at T=1013 GeV, in substantial agreement with estimates used in previous phenomenological analyses. These values apply to the Standard Model with a Higgs-boson mass of 125 GeV. The dependence of the numerical coefficient on the temperature T is due to the renormalisation group running. The leading linear and logarithmic dependencies of the flavour relaxation rate on the gauge and top-quark couplings are extracted, such that the results presented in this work can readily be applied to extensions of the Standard Model. We also derive the production rate of light (compared to the temperature) sterile right-handed neutrinos, a calculation that relies on the same methods. We confirm most details of earlier results, but find a substantially larger contribution from the t-channel exchange of fermions.
AB - Using the Closed Time Path (CTP) approach, we perform a systematic leading order calculation of the relaxation rate of flavour correlations of left-handed Standard Model leptons. This quantity is of pivotal relevance for flavoured leptogenesis in the Early Universe, and we find it to be 5.19×10-3T at T=107 GeV and 4.83×10-3T at T=1013 GeV, in substantial agreement with estimates used in previous phenomenological analyses. These values apply to the Standard Model with a Higgs-boson mass of 125 GeV. The dependence of the numerical coefficient on the temperature T is due to the renormalisation group running. The leading linear and logarithmic dependencies of the flavour relaxation rate on the gauge and top-quark couplings are extracted, such that the results presented in this work can readily be applied to extensions of the Standard Model. We also derive the production rate of light (compared to the temperature) sterile right-handed neutrinos, a calculation that relies on the same methods. We confirm most details of earlier results, but find a substantially larger contribution from the t-channel exchange of fermions.
UR - http://www.scopus.com/inward/record.url?scp=84886244591&partnerID=8YFLogxK
U2 - 10.1016/j.nuclphysb.2013.08.020
DO - 10.1016/j.nuclphysb.2013.08.020
M3 - Article
AN - SCOPUS:84886244591
SN - 0550-3213
VL - 877
SP - 1
EP - 35
JO - Nuclear Physics, Section B
JF - Nuclear Physics, Section B
IS - 1
ER -