CP Violation for the Heavens and the Earth

oleh: George Wei-Shu Hou

Format: Article
Diterbitkan: MDPI AG 2022-04-01

Deskripsi

Electroweak baryogenesis can be driven by the top quark in a general two Higgs doublet model with extra Yukawa couplings. Higgs quartics provide the first order phase transition, while extra top Yukawa coupling <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>ρ</mi><mrow><mi>t</mi><mi>t</mi></mrow></msub></semantics></math></inline-formula> can fuel the cosmic baryon asymmetry through the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>λ</mi><mi>t</mi></msub><mspace width="0.166667em"></mspace><mi>Im</mi><mspace width="0.166667em"></mspace><msub><mi>ρ</mi><mrow><mi>t</mi><mi>t</mi></mrow></msub></mrow></semantics></math></inline-formula> product, with flavor-changing <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>ρ</mi><mrow><mi>t</mi><mi>c</mi></mrow></msub></semantics></math></inline-formula> coupling as backup. The impressive ACME 2018 bound on the electron electric dipole moment calls for an extra electron coupling <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>ρ</mi><mrow><mi>e</mi><mi>e</mi></mrow></msub></semantics></math></inline-formula> for exquisite cancellation among dangerous diagrams, broadening the baryogenesis solution space. The mechanism suggests that extra Yukawa couplings echo the hierarchical structure of standard Yukawa couplings. Phenomenological consequences in the Higgs search and flavor physics are discussed, with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>μ</mi></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>τ</mi></semantics></math></inline-formula> EDM touched upon.