A New bound on CP Violation in the $\tau$ Lepton Yukawa Coupling and electroweak baryogenesis

Understand

The origin of the matter-antimatter asymmetry in the Universe is a fundamental question of physics.

• Electroweak baryogenesis is a compelling scenario for explaining it but it requires beyond the Standard Model sources of the CP symmetry violation.
• The simplest possibility is CP violation in the third generation fermion Higgs couplings, widely investigated theoretically and searched for experimentally.
• It has been found that the experimental bounds on the CP violation in the quark Yukawa couplings exclude their significant role in the electroweak baryogenesis, but it can be still played by the $\tau$ lepton Yukawa coupling.