New results in 
meson physics
M. Benayoun1 - S. Eidelman2 - K. Maltman3,4,5 - H.B. O'Connell4,6 - B. Shwartz2 - A.G. Williams4,5
1 LPNHE des Universités Paris VI et VII-IN2P3, Paris,
France
(e-mail: benayoun@in2p3.fr)
2 Budker Institute of Nuclear Physics, Novosibirsk 630090, Russia
(e-mail: eidelman@vxcern.cern.ch)
3 Mathematics and Statistics, York University, 4700 Keele St.,
North York, Ontario, Canada M3J 1P3
(e-mail: maltman@fewbody.phys.yorku.ca)
4 Department of Physics and Mathematical
Physics, University of Adelaide 5005, Australia
(e-mail: awilliam@physics.adelaide.edu.au)
5 Special Research Centre for the Subatomic Structure of Matter,
University of Adelaide 5005,
Australia
6 Department of Physics and Astronomy,
University of Kentucky,
Lexington, KY 40506, USA
(e-mail: hoconnel@ruthless.pa.uky.edu)
Received: 1 August 1997 / Revised version: 4 December 1997
Abstract
We compare the predictions of a range of existing models based
on the Vector Meson Dominance hypothesis with data on
and 
cross-sections and the phase and near-threshold behavior of the timelike
pion form factor, with the aim of determining which (if any) of these
models is capable of providing an accurate representation of the full
range of experimental data. We find that, of the models considered,
only that proposed by Bando et al.
is able to consistently account for all
information, provided one allows its parameter a to vary from
the usual value of 2 to 2.4.
Our fit with this model gives
a point-like coupling 
of magnitude 
, while the common formulation of
VMD excludes such a term. The resulting values
for the 
mass and 
and e+e-
partial widths as well as the branching ratio for the decay
obtained within the context of this model are
consistent with previous results.
Copyright Springer-Verlag
