Source of CP Violation for Baryon Asymmetry of the Universe

TL;DR

This paper proposes that the large Yukawa couplings of hypothetical fourth-generation quarks could provide the necessary CP violation to explain the Universe's baryon asymmetry, suggesting new physics beyond the Standard Model.

Contribution

It introduces the idea that fourth-generation quarks with large Yukawa couplings can significantly enhance CP violation, offering a viable explanation for baryon asymmetry.

Findings

Large Yukawa couplings can enhance CP violation by over 10^13.

Hints of large CP violation observed in B_s mixing support the hypothesis.

Discovery of fourth-generation quarks at LHC would test this model.

Abstract

The baryon asymmetry of the Universe requires CP violation, but the Standard Model falls short by a factor of $10^{-10}$ or more. Starting from a clue at the $B$ factories, we point out that the large Yukawa couplings of the sequential fourth generation $t^\prime$ and $b^\prime$ quarks can provide enhancement by a factor of over $10^{13}$, making the 2-3-4 generation quark sector a viable source of CP violation for the baryon asymmetry of the Universe. With recent hints of large $\sin2\Phi_{B_s}$ in $B_s^0$-$\bar B_s^0$ mixing from the Tevatron, the ultimate test would be to discover the $t^\prime$ and $b^\prime$ quarks at the Large Hadron Collider.