Measurement of absolute branching fractions of inclusive semileptonic decays of charm and charmed-strange mesons

TL;DR

This paper reports precise measurements of inclusive semileptonic branching fractions for $D^0$, $D^+$, and $D_s^+$ mesons using CLEO-c data, providing insights into charm meson decay dynamics and testing isospin symmetry.

Contribution

First measurement of inclusive semileptonic branching fractions for $D^0$, $D^+$, and $D_s^+$ mesons using CLEO-c data, with implications for charm decay models.

Findings

Measured branching fractions with statistical and systematic uncertainties.

Found decay width ratios consistent with isospin symmetry and theoretical expectations.

Provided data to improve understanding of charm meson semileptonic decays.

Abstract

We have measured the inclusive semileptonic branching fractions of $D^0$, $D^+$, and $D^+_s$ mesons. For these measurements, we have used the full CLEO-c open-charm data samples, 818 pb$^{-1}$ at $E_\text{CM} = 3.774$ GeV, giving $D^0 \bar{D}^0$ and $D^+ D^-$ events, and 602 pb$^{-1}$ at $E_\text{CM} = 4.170$ GeV, giving $D^{\ast \pm}_s D^\mp_s$ events. We obtain $\mathcal{B}(D^0 \to X e^+ \nu_e) = (6.46 \pm 0.09 \pm 0.11)$%, $\mathcal{B}(D^+ \to X e^+ \nu_e) = (16.13 \pm 0.10 \pm 0.29)$%, and $\mathcal{B}(D^+_s \to X e^+ \nu_e) = (6.52 \pm 0.39 \pm 0.15)$%, where the first uncertainties are statistical and the second are systematic. From these and lifetimes obtained elsewhere, we obtain the ratios of semileptonic decay widths $\Gamma (D^+ \to X e^+ \nu_e) / \Gamma (D^0 \to X e^+ \nu_e) = 0.985 \pm 0.015 \pm 0.024$ and $\Gamma (D^+_s \to X e^+ \nu_e) / \Gamma (D^0 \to X e^+ \nu_e) = 0.828 \pm 0.051 \pm 0.025$. The ratio of $D^+$ and $D^0$ is consistent with the isospin symmetry prediction of unity, and the ratio of $D^+_s$ and $D^0$ differs from unity, as expected.