Experimental Status of the CKM Matrix

TL;DR

This paper reviews the experimental efforts to determine the CKM matrix, highlighting the progress in measurement precision, the consistency with the standard model, and ongoing challenges in confirming its unitarity.

Contribution

It provides a comprehensive review of the current experimental status of the CKM matrix and assesses its consistency with the standard model's unitarity constraints.

Findings

Overall good agreement with standard model unitarity

Progress in measurement precision of CKM parameters

Some unresolved issues in CKM matrix determination

Abstract

The CKM matrix, V, relates the quark mass and flavor bases. In the standard model, V is unitary 3X3, and specified by four arbitrary parameters, including a phase allowing for $CP$ violation. We review the experimental determination of V, including the four parameters in the standard model context. This is an active field; the precision of experimental measurements and theoretical inputs continues to improve. The consistency of the determination with the standard model unitarity is investigated. While there remain some issues the overall agreement with standard model unitarity is good.