First Order Electroweak Phase Transition from Weakly Coupled sub-GeV Physics and Possible Connection to Fermion Flavor

Abstract

We propose that the dynamics of a scalar $\varphi$ of mass $O(10)$ MeV that is weakly coupled to the Higgs can lead to a first order electroweak phase transition, fulfilling a key requirement for baryogenesis. Stability of the model near the weak scale requires a suppressed - possibly vanishing - top Yukawa coupling to the Higgs before the transition which rises to the Standard Model value afterwards. This can be accomplished through the dynamics of $\varphi$ via a dimension-5 operator. We conjecture that the entire Standard Model flavor structure could turn on, mutatis mutandis, after the electroweak phase transition, via dimension-5 interactions of $\varphi$ suppressed by scales ranging from $O(10^3)$ TeV to near Planck mass. Due to its suppressed couplings, $\varphi$ is long-lived and can lead to missing energy signals in rare kaon decays, which can be probed by the KOTO experiment.

8 pages, 4 figures. Replaced with the version accepted for publication in PRD. Several references and some discussion of baryogenesis added

References in corpus (10)

• Singlet Higgs Phenomenology and the Electroweak Phase Transition
• Dynamics of Non-renormalizable Electroweak Symmetry Breaking
• Strong First Order Electroweak Phase Transition in the CP-Conserving 2HDM Revisited
• Higgs Self-Coupling as a Probe of Electroweak Phase Transition
• Dynamics of Electroweak Phase Transition In Singlet-Scalar Extension of the Standard Model
• Revisiting supernova constraints on a light CP-even scalar
• Study of the $K_L\to {\pi }^0\nu \overline{\nu }$ Decay at the J-PARC KOTO Experiment
• Flavor Cosmology: Dynamical Yukawas in the Froggatt-Nielsen Mechanism
• Electroweak Phase Transition with an SU(2) Dark Sector
• Lepton-mediated electroweak baryogenesis, gravitational waves and the $4\tau$ final state at the collider

Cited by in corpus (3)

• A new perspective on the electroweak phase transition in the Standard Model Effective Field Theory
• Screening the Higgs portal
• Shedding light on the electroweak phase transition from exotic Higgs boson decays at the lifetime frontiers