Measurement OF Ds+ -> l+ nu and the Decay Constant fDs

TL;DR

This paper reports preliminary measurements of the decay constant fDs and its ratio to fD+ using CLEO-c data, providing important tests for theoretical models of meson decay constants.

Contribution

The paper presents the first measurement of fDs and its ratio to fD+ using CLEO-c data at 4.170 GeV, with improved precision over previous results.

Findings

fDs = 280.1 +/- 11.6 +/- 6.0 MeV

fDs/fD+ = 1.26 +/- 0.11 +/- 0.03

Preliminary results support existing theoretical predictions.

Abstract

I report preliminary CLEO-c results on purely leptonic decays of the Ds using 195/pb of data at 4.170 GeV. We measure fDs = 280.1 +/- 11.6 +/- 6.0 MeV, and fDs/fD+ = 1.26 +/- 0.11 +/- 0.03.