Do the Small Numbers in the Quark Mixing arise from New Physics?

TL;DR

This paper proposes that the small values in the CKM matrix originate from new physics beyond the Standard Model, specifically through an extension involving an up-type vector-like quark, which explains quark masses and mixing.

Contribution

It introduces a novel conjecture linking small CKM elements to new physics and demonstrates a model with an up-type vector-like quark that reproduces observed quark properties.

Findings

Small CKM matrix elements can be generated by physics beyond the Standard Model.

An extension with an up-type vector-like quark yields realistic quark masses.

The model aligns with experimental measurements of the CKM matrix.

Abstract

We put forward the conjecture that the small numbers in the $V_\text{CKM}$ matrix, are generated by physics beyond the Standard Model. We identify as small numbers $V_{ub}$ and the strength of CP violation, measured by $|\text{Im}Q|$, where $Q$ stands for a rephasing invariant quartet of $V_\text{CKM}$. We illustrate how the conjecture can be realised in the context of an extension of the Standard Model where an up-type vector-like quark is introduced leading to a realistic spectrum of quark masses and an effective $V_\text{CKM}$ in agreement with experiment.