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Article
Report number	arXiv:2111.03082 ; KEK-TH-2364 ; CERN-TH-2021-183 ; TU-1137
Title	Baryon Asymmetry of the Universe from Lepton Flavor Violation
Author(s)	Mukaida, Kyohei (KEK, Tsukuba ; Sokendai, Tsukuba) ; Schmitz, Kai (CERN) ; Yamada, Masaki (Tohoku U., Astron. Inst. ; Tohoku U.)
Publication	2022-06-28
Imprint	2021-11-04
Number of pages	10
Note	9 pages, 2 figures; v2: added missing term in transport eq., typos corrected
In:	Phys. Rev. Lett. 129 (2022) 011803
DOI	10.1103/PhysRevLett.129.011803 (publication)
Subject category	astro-ph.CO ; Astrophysics and Astronomy ; hep-ph ; Particle Physics - Phenomenology
Abstract	Charged-lepton flavor violation (CLFV) is a smoking-gun signature of physics beyond the Standard Model. The discovery of CLFV in upcoming experiments would indicate that CLFV processes must have been efficient in the early Universe at relatively low temperatures. In this letter, we point out that such efficient CLFV interactions open up new ways of creating the baryon asymmetry of the Universe. First, we quote the two-loop corrections from charged-lepton Yukawa interactions to the chemical transport in the Standard Model plasma, which imply that nonzero lepton flavor asymmetries summing up to $B-L = 0$ are enough to generate the baryon asymmetry. Then, we describe two scenarios of what we call {\it leptoflavorgenesis}, where efficient CLFV processes are responsible for the generation of primordial lepton flavor asymmetries that are subsequently converted to a baryon asymmetry by weak sphaleron processes. Here, the conversion factor from lepton flavor asymmetry to baryon asymmetry is suppressed by charged-lepton Yukawa couplings squared, which provides a natural explanation for the smallness of the observed baryon-to-photon ratio.
Copyright/License	preprint: (License: arXiv nonexclusive-distrib 1.0) publication: Published by the American Physical Society (License: CC-BY-4.0)

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