A new sum rule to determine Vub/Vcb

Abstract

We present a new sum rule which does not contain any Landau-pole effect and allows a determination of Vub/Vcb with a theoretical error of O(5%).

Comments: LaTex file, 5 pages, talk given at the LEPTRE Conference, Rome 18-20 April 2001,to be published in the proceedings, no figures; some typos corrected