Determination of |Vub|

Abstract

The element Vub of the CKM mixing matrix is the smallest of the quark couplings and is crucial in understanding CP violation in the B system. In this review, we discuss the present status of the determination of its magnitude, which involves a significant effort both experimentally and theoretically. Decisive progress has been achieved in recent years, thanks in part to the large data sets that have become available at the B factories. Based on these data we propose an average |Vub| value of (3.67 \pm 0.47)x10^{-3}, which has an uncertainty of 13%. With the experimental and theoretical progress expected in the next few years a determination to an accuracy of 10%, or better, seems feasible.