Observation of D^+ to eta e^+ nu_e

TL;DR

This paper reports the first observation of the semileptonic decay D^+ to eta e^+ nu_e using data from the CLEO-c detector, and sets new upper limits for related decay modes, advancing understanding of charm meson decays.

Contribution

It provides the first experimental evidence for D^+ to eta e^+ nu_e decay and significantly improves upper limits for other related decay channels.

Findings

First observation of D^+ to eta e^+ nu_e decay

Set more restrictive upper limits for D^+ to eta' e^+ nu_e and D^+ to phi e^+ nu_e

Utilized 281 pb^-1 data sample at psi(3770) resonance

Abstract

Using a 281 pb^-1 data sample collected at the psi(3770) resonance with the CLEO-c detector at the Cornell Electron Storage Ring, we report the first observation of D^+ to eta e^+ nu_e. We also set upper limits for D^+ to eta' e^+ nu_e and D^+ to phi e^+ nu_e that are about two orders of magnitude more restrictive than those obtained by previous experiments.