  Using data collected at the psi(3770) resonance with the CLEO-c detector at
the Cornell e+e- storage ring, we present improved measurements of the absolute
branching fractions of D+ decays to K0B e+ nu_e, pi0 e+ nu_e, K0B* e+ nu_e, and
rho0 e+ nu_e, and the first observation and absolute branching fraction
measurement of D+ --> omega e+ nu_e. We also report the most precise tests to
date of isospin invariance in semileptonic D0 and D+ decays.

High Energy Physics - Experiment