DOI 10.1007/s100529901061
Measurement of the strong coupling
constant
and the vector and axial-vector spectral
functions in hadronic tau decays
The OPAL Collaboration
K. Ackerstaff8 - et al.
8CERN, European Organisation for Particle Physics, CH-1211 Geneva 23, Switzerland
Received: 23 June 1998 / Published online: 19 February 1999
Abstract
The spectral functions of the vector current and the axial-vector
current have been measured in hadronic decays using the OPAL
detector at LEP. Within the framework of the Operator Product
Expansion a simultaneous determination of the strong coupling constant
, the non-perturbative operators of dimension 6 and 8 and of
the gluon condensate has been performed. Different perturbative
descriptions have been compared to the data. The Contour Improved
Fixed Order Perturbation Theory gives
at the
-mass
scale and
at the Z0-mass scale. The values obtained
for
using Fixed Order Perturbation Theory or
Renormalon Chain Resummation are
and
smaller,
respectively. The running of the strong coupling between
and
has been tested from
direct fits to the integrated differential hadronic decay rate
.A test of the saturation of QCD sum rules at the
-mass scale has
been performed.
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