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arXiv · 1411.1765

Right-handed neutrino production rate at T > 160 GeV

I. Ghisoiu·M. Laine
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Abstract

The production rate of right-handed neutrinos from a Standard Model plasma at a temperature above a hundred GeV has previously been evaluated up to NLO in Standard Model couplings (g ~ 2/3) in relativistic (M ~ pi T) and non-relativistic regimes (M >> pi T), and up to LO in an ultrarelativistic regime (M < gT). The last result necessitates an all-orders resummation of the loop expansion, accounting for multiple soft scatterings of the nearly light-like particles participating in 1 <-> 2 reactions. In this paper we suggest how the regimes can be interpolated into a result applicable for any right-handed neutrino mass and at all temperatures above 160 GeV. The results can also be used for determining the lepton number washout rate in models containing right-handed neutrinos. Numerical results are given in a tabulated form permitting for their incorporation into leptogenesis codes. We note that due to effects from soft Higgs bosons there is a narrow intermediate regime around M ~ g^{1/2} T in which our interpolation is phenomenological and a more precise study would be welcome.

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I. Ghisoiu, M. Laine. 2014-12-17. Right-handed neutrino production rate at T > 160 GeV. https://doi.org/10.1088/1475-7516%2F2014%2F12%2F032

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