Electromagnetic leptogenesis — an EFT-consistent analysis via Wilson coefficients. Part I. Low-scale, non-resonant regime

[摘要] We analyse electromagnetic leptogenesis within the framework of an effective field theory, where the dynamics is governed by the gauge-invariant dipole operator \documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${\mathcal{O}}_{NB}=\left(\overline{L}{\sigma}^{\mu \nu }N\right)\widetilde{H}{B}_{\mu \nu }$$\end{document}. The Wilson coefficient CNB is matched at one loop and evolved to the electroweak scale via renormalisation-group (RG) running. After electroweak symmetry breaking, we compute flavour-dependent decay widths and CP asymmetries for the two-body modes N → νγ and N → νZ, and solve the fully flavoured Boltzmann equations. In the N1-dominated regime, the freeze-out baryon asymmetry is \documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${Y}_{B}^{\text{FO}}\lesssim {1}{0}^{-{17}}$$\end{document}, far below the observed value \documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${Y}_{B}^{\text{obs}}\simeq 8.7\times {10}^{-11}$$\end{document}. The suppression is structural: gauge invariance forces a Higgs insertion; therefore the dipole coupling scales as \documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\mu \propto v/{M}_{\psi}^{2}$$\end{document}, while the matched Wilson coefficient CNB is loop-generated and further suppressed by RG running. We note that in the quasi-degenerate limit the self-energy resonance can be operative and suggest a plausible path to \documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${Y}_{B}^{\text{obs}}$$\end{document}.

[发布日期] 2025-12-01

[关键词] Baryo-and Leptogenesis;Early Universe Particle Physics;Sterile or Heavy Neutrinos