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  • Letter
  • Open Access

CP asymmetries and higher-order unitarity relations

Tomáš Blažek* and Peter Maták†

  • Department of Theoretical Physics, Comenius University, Mlynská dolina, 84248 Bratislava, Slovak Republic

  • *tomas.blazek@fmph.uniba.sk
  • †peter.matak@fmph.uniba.sk
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Phys. Rev. D 103, L091302 – Published 26 May, 2021

DOI: https://doi.org/10.1103/PhysRevD.103.L091302

Abstract

The main focus of this paper is to introduce a new method to control perturbative calculations of CP asymmetric reaction rates in Boltzmann equation. CP asymmetries in particle reactions are traditionally calculated in terms of complex couplings, Feynman integrals, and Cutkosky rules. We use an expansion of the S-matrix unitarity condition instead, obtaining a general expression for the asymmetries without reference to the imaginary part of the loops. Asymmetry cancelations implied by CPT and unitarity are manifested in a diagrammatic way and easy to track at any order of perturbation theory. We demonstrate the power of this general framework within the right-handed neutrino and top-quark scattering asymmetries in seesaw type-I leptogenesis.

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Outline

Information

Phys. Rev. D 103, L091302– Published 26 May, 2021
  • Received 12 February 2021
  • Accepted 22 April 2021
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

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