Observation of the Radiative Decay $D^{*+}\to D^{+}\gamma$

TL;DR

This paper reports the first significant observation of the radiative decay D*+ to D+ gamma, measuring its branching ratio and providing high-precision data on D*+ decay modes.

Contribution

The study presents the first observation of D*+ -> D+ gamma decay with a 4 sigma significance and precise measurements of related D*+ branching fractions.

Findings

Observation of D*+ -> D+ gamma decay at 4 sigma significance

Measured branching ratio B(D*+ -> D+ gamma) = 0.017 +- 0.004 +- 0.003

High-precision measurements of other D*+ decay branching fractions

Abstract

We have observed a signal for the decay D*+ -> D+ gamma at a significance of 4 standard deviations. From the measured branching ratio B(D*+ -> D+ gamma)/B(D*+ -> D+ pi0)=0.055 +- 0.014 +- 0.010 we find B(D*+ -> D+ gamma)= 0.017 +- 0.004 +- 0.003, where the first uncertainty is statistical and the second is systematic. We also report the highest precision measurements of the remaining D*+ branching fractions.