First measurement of the form factors in the decays D0→ρ- ^e+ν<inf>e</inf> and D+^→ρ0e+ν<inf>e</inf>

Abstract

The beauty to up quark coupling constant |Vub| can be extracted from B→ρe+νe combined with the form factors for D→K*e+νe and B→Vℓ+ℓ- and D→ρe+ν e. Using the entire CLEO-c ψ(3770)→DD̄ event sample, corresponding to an integrated luminosity of 818 pb-1 and approximately 5.4×106 DD̄ events, we measure the form factors for the decays D0→ρ-e+νe and D +→ρ0e+νe for the first time and the branching fractions with improved precision. A four-dimensional unbinned maximum likelihood fit determines the form factor ratios to be V(0)/A 1(0)=1.48±0.15±0.05 and A2(0)/A 1(0)=0.83±0.11±0.04. Assuming Cabibbo-Kobayashi-Maskawa unitarity, the known D meson lifetimes, and our measured branching fractions we obtain the form factor normalizations A1(0), A2(0), and V(0). We also present a measurement of the branching fraction for D +→ωe+νe with improved precision. © 2013 American Physical Society.