Do the small numbers in the quark mixing arise from new physics?

Abstract

Abstract We put forward the conjecture that the small numbers in the $$V_\text {CKM}$$ V CKM matrix, are generated by physics beyond the Standard Model. We identify as small numbers $$V_{ub}$$ V ub and the strength of CP violation, measured by $$|\text {Im}Q|$$ | Im Q | , where Q stands for a rephasing invariant quartet of $$V_\text {CKM}$$ V 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 $$V_\text {CKM}$$ V CKM in agreement with experiment.