On the Status of $V_{td}$, $V_{ts}$ and $V_{tb}$

TL;DR

This paper reviews the precise determination of CKM matrix elements $V_{td}$, $V_{ts}$, and $V_{tb}$ within the Standard Model and explores how these might change in theories with non-unitary quark mixing.

Contribution

It analyzes the current methods for measuring CKM elements and discusses possible deviations in models beyond the Standard Model with non-unitary matrices.

Findings

CKM elements can be precisely determined within the SM

Extensions with non-unitary matrices can modify these elements

Implications for new physics searches

Abstract

The CKM matrix elements $V_{td}$, $V_{ts}$ and $V_{tb}$, while notoriously hard to measure directly in experiment, can be determined to great precision within the Standard Model (SM) with a minimal set of observables due to unitarity of $V_{\rm CKM}$. We discuss the potential modifications of these elements in extensions with non-unitary quark mixing matrices.