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Baryogenesis and EDMs in the 2HDM+CS

Björn Garbrecht, Edward Wang

Abstract

We perform the first joint analysis of baryogenesis from initial Higgs charges (also called Higgsogenesis) and EDMs in a model with two Higgs doublets, a complex scalar and a Majorana fermion. In our proposed scenario, baryogenesis happens in three steps: (1) The decay of the scalar produces an asymmetry between the two Higgs doublets which is partly transferred to fermions via Standard Model processes. (2) This asymmetry is converted into a $B-L$ charge via interactions mediated by the Majorana fermion. (3) The weak sphaleron processes partially convert the resulting $B-L$ charge into a $B$ asymmetry. We perform a numerical analysis of baryogenesis and the EDM contributions and find that, due to resonant enhancement, baryogenesis is possible with singlet masses as low as $10^5$ GeV. We also find that for some parameters, the model can give large contributions to the electron and neutron EDM while also producing baryogenesis. The present scenario offers a new perspective on interpreting observational bounds in terms of cosmology: Because it relies on out-of-equilibrium decays, the questions of baryogenesis and $CP$ violation in the Higgs sector may be linked with EDM signals without the additional assumption of a first order electroweak phase transition.

Baryogenesis and EDMs in the 2HDM+CS

Abstract

We perform the first joint analysis of baryogenesis from initial Higgs charges (also called Higgsogenesis) and EDMs in a model with two Higgs doublets, a complex scalar and a Majorana fermion. In our proposed scenario, baryogenesis happens in three steps: (1) The decay of the scalar produces an asymmetry between the two Higgs doublets which is partly transferred to fermions via Standard Model processes. (2) This asymmetry is converted into a charge via interactions mediated by the Majorana fermion. (3) The weak sphaleron processes partially convert the resulting charge into a asymmetry. We perform a numerical analysis of baryogenesis and the EDM contributions and find that, due to resonant enhancement, baryogenesis is possible with singlet masses as low as GeV. We also find that for some parameters, the model can give large contributions to the electron and neutron EDM while also producing baryogenesis. The present scenario offers a new perspective on interpreting observational bounds in terms of cosmology: Because it relies on out-of-equilibrium decays, the questions of baryogenesis and violation in the Higgs sector may be linked with EDM signals without the additional assumption of a first order electroweak phase transition.

Paper Structure

This paper contains 17 sections, 106 equations, 2 figures.

Table of Contents

  1. Introduction
  2. The Model
  3. Baryogenesis
  4. Equilibrium Conditions
  5. $T > e15GeV$:
  6. $e13GeV < T < e15GeV$:
  7. $10^{11-12} GeV < T < e13GeV$:
  8. $e9GeV < T < 10^{11-12} GeV$:
  9. $e6GeV < T < e9GeV$:
  10. Kinetic Equations
  11. Rates
  12. EDMs
  13. Numerical Results
  14. Conclusion
  15. Averaged Rates
  16. ...and 2 more sections

Figures (2)

  • Figure 1: Diagrammatic representation of the $CP$-violating source terms.
  • Figure 2: Scan of electron (a) and neutron (b) EDM contributions from our model plotted against the asymmetry parameter $\eta_B$. The blue dashed region is the constraint for successful baryogenesis, while the orange regions are the constraints from JILA Roussy:2022cmp for the electron and from PSI Abel:2020pzs for the neutron EDMs. Also plotted are the SM predictions for the electron and neutron EDMs from Refs. Yamaguchi:2020eubDar:2000tn respectively, and the predicted sensitivities from the experiment under construction at Imperial College Tarbutt_2013 and the n2EDM experiment at PSI n2EDM:2021yah.