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The Baryon asymmetry in the Standard Model with a low cut-off

Dietrich Bodeker, Lars Fromme, Stephan J. Huber, Michael Seniuch

TL;DR

This work probes electroweak baryogenesis within the Standard Model augmented by a low-cutoff effective field theory featuring a stabilizing $\phi^6$ Higgs term. By combining a one-loop finite-temperature potential with a dimension-6 CP-violating Higgs-top operator and a WKB transport framework, the authors demonstrate a strong first-order electroweak phase transition for $m_H$ up to $\sim 170$ GeV when $M\gtrsim 500$ GeV, and show that novel CP-violating transport sources can yield a baryon asymmetry $\eta_B$ matching the observed value for natural parameter choices. The analysis links bubble-wall properties, CP-violating phases along the wall, and transport dynamics to robust predictions, while remaining consistent with current EDM and flavor constraints. The results highlight a testable scenario where collider and flavor experiments can probe the underlying cut-off scale and CP-violating operators, offering a concrete platform to refine EW baryogenesis calculations within an EFT framework.

Abstract

We study the generation of the baryon asymmetry in a variant of the standard model, where the Higgs field is stabilized by a dimension-six interaction. Analyzing the one-loop potential, we find a strong first order electroweak phase transition for Higgs masses up to at least 170 GeV. Dimension-six operators induce also new sources of CP violation. We compute the baryon asymmetry in the WKB approximation. Novel source terms in the transport equations enhance the generated baryon asymmetry. For a wide range of parameters the model predicts a baryon asymmetry close to the observed value.

The Baryon asymmetry in the Standard Model with a low cut-off

TL;DR

This work probes electroweak baryogenesis within the Standard Model augmented by a low-cutoff effective field theory featuring a stabilizing Higgs term. By combining a one-loop finite-temperature potential with a dimension-6 CP-violating Higgs-top operator and a WKB transport framework, the authors demonstrate a strong first-order electroweak phase transition for up to GeV when GeV, and show that novel CP-violating transport sources can yield a baryon asymmetry matching the observed value for natural parameter choices. The analysis links bubble-wall properties, CP-violating phases along the wall, and transport dynamics to robust predictions, while remaining consistent with current EDM and flavor constraints. The results highlight a testable scenario where collider and flavor experiments can probe the underlying cut-off scale and CP-violating operators, offering a concrete platform to refine EW baryogenesis calculations within an EFT framework.

Abstract

We study the generation of the baryon asymmetry in a variant of the standard model, where the Higgs field is stabilized by a dimension-six interaction. Analyzing the one-loop potential, we find a strong first order electroweak phase transition for Higgs masses up to at least 170 GeV. Dimension-six operators induce also new sources of CP violation. We compute the baryon asymmetry in the WKB approximation. Novel source terms in the transport equations enhance the generated baryon asymmetry. For a wide range of parameters the model predicts a baryon asymmetry close to the observed value.

Paper Structure

This paper contains 7 sections, 39 equations, 1 figure.

Table of Contents

  1. Introduction
  2. The strength of the phase transition
  3. The bubble properties
  4. CP violation
  5. Transport equations
  6. Numerical Results
  7. Conclusions

Figures (1)

  • Figure 1: The wall thickness $L_{\rm w}$ as a function of the Higgs-mass $m_H$ for several values of $M$, which are given in units of GeV. In addition lines of constant $\xi$ are shown.