Constraints on Semileptonic Form-factors from Dispersive Sum Rules

Abstract

I briefly discuss the derivation of dispersive sum rules constraining semileptonic form-factors. I outline the use of these constraints in the context of charmless semileptonic decays and suggest how, in combination with other theoretical and experimental information, they may reduce the uncertainties in the extraction of $V_{ub}$.

Comments: 6 pages, 1 ps figure included. Uses sprocl.sty. Talk presented at the 2nd Conference on B Physics and CP Violation, Honolulu, Hawaii, March 24-27 1997