Model-independent access to the structure of quark flavor mixing

TL;DR

This paper demonstrates that the observed quark flavor mixing patterns can be understood through the limits of heavy quark masses, revealing fundamental relations and the role of CP violation in the Standard Model.

Contribution

It provides a model-independent analysis linking quark mixing patterns to heavy quark mass limits and clarifies the role of CP violation through CKM matrix elements.

Findings

Quark mixing patterns emerge in heavy quark mass limits.

Relations like |V_{ub}/V_{cb}| ~ sqrt(m_u/m_c) are justified.

CP violation strength relates to CKM matrix corners.

Abstract

We show that the observed pattern of quark flavor mixing, such as |V_{us}| \simeq |V_{cd}|, |V_{cb}| \simeq |V_{ts}|, |V_{cd}/V_{td}| \simeq |V_{cs}/V_{ts}| \simeq |V_{tb}/V_{cb}| and |V_{ub}/V_{cb}| < |V_{td}/V_{ts}|, can essentially be understood in the chiral and heavy quark mass limits. In particular, the phenomenologically successful relations |V_{ub}/V_{cb}| \sim \sqrt{m_u/m_c} and |V_{td}/V_{ts}| \simeq \sqrt{m_d/m_s} can be reasonably conjectured in the m_b \to \infty and m_t \to \infty limits, respectively. We stress that the strength of weak CP violation in the quark sector is determined by the moduli of the four corner elements of the Cabibbo-Kobayashi-Maskawa matrix. A comparison between strong and weak CP-violating effects in the standard model is also made.