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

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 $V_{\mathrm{CKM}}$. We discuss the potential modifications of these elements in extensions with non-unitary quark mixing matrices.

Comments: 7 pages; talk given at the 6th International Workshop on the CKM Unitarity Triangle, Warwick, England, September 6th - 10th, 2010