Measurement of the ratio Beta(D+ -> pi(0)l+nu) Beta(D+ -> (K)over-bar(o)l+nu)

Abstract

Using the CLEO-II detector, the branching ratio of the Cabibbo suppressed decay D+ --> pi0l+nu, relative to the branching ratio of the Cabibbo favored decay D+ --> K0l+nuBAR, is measured to be B(D+ --> pi0l+nu)/B(D+ --> K0l+nuBAR) = (8.5 +/- 2.7 +/- 1.4)%. From this ratio, the product of the ratio of Cabibbo-Kobayashi-Maskawa (CKM) matrix elements, \V(cd)/V(cs)\2, and the form factors at q2 = 0, \f+pi(0)/f+K(0)\2, is determined to be \V(cd)/V(cs)\2\f+pi(0)/f+K(0)\2 = 0.085 +/- 0.027 +/- 0.014.