Absolute Branching Fraction Measurements for D^+ and D^0 Inclusive Semileptonic Decays

TL;DR

This paper reports precise measurements of inclusive semileptonic decay branching fractions for D^+ and D^0 mesons, confirming isospin invariance and analyzing positron spectra using data from the CLEO-c detector.

Contribution

First precise measurements of D^+ and D^0 inclusive semileptonic branching fractions using psi(3770) data, confirming isospin symmetry at the 3% level.

Findings

Br(D^0 -> Xe^+ nu_e) = (6.46 ± 0.17 ± 0.13)%

Br(D^+ -> Xe^+ nu_e) = (16.13 ± 0.20 ± 0.33)%

Gamma_{D^+}^sl / Gamma_{D^0}^sl = 0.985 ± 0.028 ± 0.015

Abstract

We present measurements of the inclusive branching fractions for the decays D^+ -> X e^+ nu_e and D^0 -> X e^+ nu_e, using 281 pb^-1 of data collected on the psi(3770) resonance with the CLEO-c detector. We find Br(D^0 ->Xe^+\nu_e) = (6.46 \pm 0.17 \pm 0.13)% and Br((D^+ -> Xe^+nu_e) = (16.13 \pm 0.20 \pm 0.33)%. Using the known D meson lifetimes, we obtain the ratio Gamma{D^+}^sl/Gamma_{D^0}^sl= 0.985\pm 0.028\pm 0.015, confirming isospin invariance at the level of 3%. The positron momentum spectra from D^+ and D^0 have consistent shapes.