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Updated: Jul 23, 2025

Setting Limits on Supersymmetry Using Simplified Models
Published on: November 15, 2013
New Constraint on Primordial Lepton Flavor Asymmetries
Valerie Domcke1,2, Kohei Kamada3, Kyohei Mukaida4,5
1Theoretical Physics Department, CERN, 1211 Geneva 23, Switzerland.
Abstract:
A chiral chemical potential present in the early Universe can source helical hypermagnetic fields through the chiral plasma instability. If these hypermagnetic fields survive until the electroweak phase transition, they source a contribution to the baryon asymmetry of the Universe. In this Letter, we demonstrate that lepton flavor asymmetries above |μ|/T∼9×10^{-3} trigger this mechanism even for vanishing total lepton number. This excludes the possibility of such large lepton flavor asymmetries present at temperatures above 10^{6} GeV, setting a constraint which is about 2 orders of magnitude stronger than the current CMB and BBN limits.
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