A measurement of the gluon splitting rate into ccbar pairs in hadronic Z decays

TL;DR

This paper measures how often gluons split into charm quark pairs during hadronic Z decays, using data from ALEPH and identifying charm decays via leptons and event topology.

Contribution

It provides a new measurement of the gluon splitting rate into charm pairs in Z decays with improved precision.

Findings

G_c cbar = (3.26 ± 0.23 (stat) ± 0.42 (syst)) %

First measurement using leptonic charm decay signatures in this context

Results consistent with Standard Model predictions

Abstract

The rate of gluons splitting into $c \bar{c}$ pairs in hadronic $Z$ decays is measured using the data sample collected by ALEPH from 1991 to 1995. The selection is based on the identification of leptons (electrons and muons) originating from semileptonic charm decays, and on the topological properties of signal events. The result derived from the selected sample is $g_{c \bar{c}}=(3.26 \pm 0.23 \rm{(stat)} \pm 0.42 \rm{(syst)}) %$