2 research outputs found
Semileptonic decays and Charmonium distribution amplitude
In this paper we study the semileptonic decays of the meson in the
Light-Cone Sum Rule (LCSR) approach. The result for each channel depends on the
corresponding distribution amplitude of the final meson. For the case of
decaying into a pseudoscalar meson, to twist-3 accuracy only the leading twist
distribution amplitude (DA) is involved if we start from a chiral current. If
we choose a suitable chiral current in the vector meson case, the main twist-3
contributions are also eliminated and we can consider the leading twist
contribution only. The leading twist distribution amplitudes of the charmonium
and other heavy mesons are given by a model approach in the reasonable way.
Employing this charmonium distribution amplitude we find the cross section
which is consistent with Belle
and BaBar's data. Based on this model, we calculate the form factors for
various decay modes in the corresponding regions. Extrapolating the form
factors to the whole kinetic regions, we get the decay widths and branching
ratios for various decay modes including their modes when they are
kinematically accessible.Comment: Changed content partially, Added references, 16 pages,2 figure
Spin Structure of the Pion in a Light-Cone Representation
The spin structure of the pion is discussed by transforming the wave function
for the pion in the naive quark model into a light-cone representation. It is
shown that there are higher helicity () states in
the full light-cone wave function for the pion besides the ordinary helicity
() component wave functions as a consequence from
the Melosh rotation relating spin states in light-front dynamics and those in
instant-form dynamics. Some low energy properties of the pion, such as the
electromagnetic form factor, the charged mean square radius, and the weak decay
constant, could be interrelated in this representation with reasonable
parameters.Comment: 15 Latex pages, 2 figures upon reques