DOI 10.1007/s100529800848
Flavor symmetry breaking and mixing effects
in the
and
transition form factors
T. Feldmann - P. Kroll
Department of Theoretical Physics, University of Wuppertal,
D-42097 Wuppertal, Germany
(e-mail: kroll@theorie.physik.uni-wuppertal.de)
Received: 13 November 1997 / Revised version: 13 January 1998 / Published online: 10 March 1998
Abstract
We reanalyze the and
transition form factors within the modified hard scattering approach
on the basis of new experimental data from CLEO [CLEO97] and L3
[L397]. Our approach perfectly describes the experimental data
over a wide range of the virtuality of the probing photon,
1 GeV
GeV2. The analysis provides hints that
the conventional flavor octet-singlet scheme for the
-
mixing is too simple. A more general mixing scheme on the other hand,
involving two mixing angles, leads to a very good description of the
transition form factors and also accounts for the two-photon decay
widths of the
and
mesons as well as for the ratio of the
widths for the
and
decays. We also investigate the questions of possible deviations of
the
and
distribution amplitudes from the asymptotic
form and of eventual intrinsic charm in the
and
mesons.
We estimate the charm decay constant of the
meson
to lie within the range -65 MeV
MeV.
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