Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Baryogenesis in $SU(2)_{L}$ multiplet models

Kiyoto Ogawa, Masanori Tanaka

Abstract

We investigate baryogenesis in Standard Model (SM) extensions with new $SU(2)_L$ multiplet fields. We focus on sphalerogenesis, in which the baryon asymmetry of the Universe (BAU) is generated through the gradual decoupling of CP-violating electroweak (EW) sphaleron-like processes. We show that the observed BAU can be reproduced when the new fields possess CP-violating Yukawa interactions, which leave a CP-violating dimension-six operator involving the $SU(2)_L$ gauge fields at low energies. As representative examples, we study models with fermionic $SU(2)_L$ quintuplets and septuplets, and find that these field masses should be $\mathcal{O}(1)\,\mathrm{TeV}$ to explain the BAU. We also show that viable parameter regions for the BAU are consistent with current bounds on the electron electric dipole moment and thoroughly probed by future measurements such as ACME III and by mono-lepton searches at the HL-LHC. Our results provide a concrete and phenomenologically testable ultraviolet completion of sphalerogenesis.

Baryogenesis in $SU(2)_{L}$ multiplet models

Abstract

We investigate baryogenesis in Standard Model (SM) extensions with new multiplet fields. We focus on sphalerogenesis, in which the baryon asymmetry of the Universe (BAU) is generated through the gradual decoupling of CP-violating electroweak (EW) sphaleron-like processes. We show that the observed BAU can be reproduced when the new fields possess CP-violating Yukawa interactions, which leave a CP-violating dimension-six operator involving the gauge fields at low energies. As representative examples, we study models with fermionic quintuplets and septuplets, and find that these field masses should be to explain the BAU. We also show that viable parameter regions for the BAU are consistent with current bounds on the electron electric dipole moment and thoroughly probed by future measurements such as ACME III and by mono-lepton searches at the HL-LHC. Our results provide a concrete and phenomenologically testable ultraviolet completion of sphalerogenesis.

Paper Structure

This paper contains 12 sections, 49 equations, 4 figures, 1 table.

Table of Contents

  1. Introduction
  2. Electroweak sphaleron configuration
  3. Estimation of CP asymmetry in EW sphaleron transition
  4. Sphalerogenesis with the EW-Weinberg operator
  5. Sphaleron-like transition rate
  6. Boltzmann equation for sphalerogenesis
  7. Application to the $SU(2)_{L}$ multiplet models
  8. EW-Weinberg operator in the $SU(2)_{L}$ multiplet models
  9. Electron electric dipole moment with $SU(2)_{L}$ multiplets
  10. Numerical results
  11. Discussions and Conclusions
  12. Sphaleron action

Figures (4)

  • Figure 1: Temperature dependence of the sphaleron-like transition rate in the $(\alpha,\beta)$ plane. The black solid contours show the boundary defined by Eq. \ref{['eq:sph_decoupling']}. Sphaleron-like transitions inside (outside) the contours are active (inactive).
  • Figure 2: [Left] Temperature evolution of $n_{B}/s$ for $\Lambda = 60\,{\rm TeV}$ and $\kappa_{\rm CP} = 2.5$. The red band indicates the observed value of $n_{B}/s$ in Eq. \ref{['eq:BAU']}. The gray dashed line marks the sphaleron decoupling temperature $T_{\rm sph} = 133.3\,{\rm GeV}$. [Right] Cutoff-scale dependence of the baryon asymmetry for each value of $\kappa_{\rm CP}$. The blue region is excluded by the current electron EDM bound from JILA Roussy:2022cmp, using Eq. \ref{['eq:EDM_EFT']}. For the right side of the black solid line, Eq. \ref{['eq:kappa_range']} is not satisfied.
  • Figure 3: Parameter region constrained by electron EDM measurements in the case $m_A=m_B$. The blue region is excluded using Eq. \ref{['eq:EDM_EFT']}, while the green region is excluded by the full result in Eq. \ref{['eq:eEDM_Full']}.
  • Figure 4: Parameter region where the observed BAU can be explained (red region) for each benchmark point within the range for $\kappa_{\rm CP}$ in Eq. \ref{['eq:kappa_range']}. The definition of the green regions is the same as in Fig. \ref{['fig:mAmB_2dim_EFT']}. The purple line shows the current indirect bound from mono-lepton searches at the LHC with $\sqrt{s} =13\,{\rm TeV}$ and $36\,{\rm fb}^{-1}$Ostdiek:2015agaMatsumoto:2017vfuMatsumoto:2018ioi. The blue line shows the expected bound from the same process at the HL-LHC with $\sqrt{s} =14\,{\rm TeV}$ and $3\,{\rm ab}^{-1}$Matsumoto:2018ioiDiLuzio:2018jwd. The magenta line corresponds to the contour with $d_{e}/e = 10^{-31}\,{\rm cm}$.