Flavor Cosmology: Dynamical Yukawas in the Froggatt-Nielsen Mechanism

Abstract

Can the cosmological dynamics responsible for settling down the present values of the Cabibbo-Kobayashi-Maskawa matrix be related to electroweak symmetry breaking? If the Standard Model Yukawa couplings varied in the early universe and started with order one values before electroweak symmetry breaking, the CP violation associated with the CKM matrix could be the origin of the matter-antimatter asymmetry. The large effective Yukawa couplings which lead to the enhanced CP violation can also help in achieving a strong first-order electroweak phase transition. We study in detail the feasibility of this idea by implementing dynamical Yukawa couplings in the context of the Froggatt--Nielsen mechanism. We discuss two main realizations of such a mechanism, related phenomenology, cosmological and collider bounds, and provide an estimate of the baryonic yield. A generic prediction is that this scenario always features a new scalar field below the electroweak scale. We point out ways to get around this conclusion.

41 pages, 14 figures; v2:Section 4.3 updated with corrected figures 2 and 3. Rest of paper unchanged; v3: version to be published in JHEP (a few clarifications added)

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Cited by in corpus (13)

• CP-violation for Electroweak Baryogenesis from Dynamical CKM Matrix
• The minimal fermionic model of electroweak baryogenesis
• Minimal Froggatt-Nielsen Textures
• Filtered asymmetric dark matter during the Peccei-Quinn phase transition
• Cosmologically Varying Kinetic Mixing
• Dynamical axion misalignment with small instantons
• Reviving keV sterile Neutrino Dark Matter
• Dark matter production through a non-thermal flavon portal
• Gravitational waves from cosmic strings in Froggatt-Nielsen flavour models
• Seesaw neutrino dark matter by freeze-out
• Exploring CP-violation in $Y=0$ inert triplet with real singlet
• First Order Electroweak Phase Transition from Weakly Coupled sub-GeV Physics and Possible Connection to Fermion Flavor
• Cosmological Stasis from Field-Dependent Decay