******** CTCD/NTHU HEP Seminar ********

Speaker ：Prof. Hsiang-Nan Li (AS)

Title ：Lepton sourced baryon asymmetry in the fourth-generation model

Time ：12:30-13:30, Thursday, 2025/12/4

Place ：R521, 5F, General Building II, Nat'l Tsing Hua Univ.

Host ： Prof. Chong-Sun Chu (NTHU)

Abstract:
We demonstrate that the observed baryon asymmetry in the Universe
can be accommodated in the extended Standard Model with sequential
fourth generation fermions (SM4). We first construct the dimension-6
effective operators $(\Phi^\dagger\Phi)\bar f\Phi f$ induced by
fourth-generation heavy quarks, which contain the $CP$ violation
(CPV) source from the $4\times 4$ CKM matrix, $\Phi$ ($f$) being a
Higgs doublet (fermion field). These operators, as implemented into
the formulation for the electroweak baryogenesis, lead to the
baryon-over-photon ratio $\eta_B\approx 10^{-10}$.