307 research outputs found
Pion Light-Cone Wave Functions and Light-Front Quark Model
We discuss a relation between the light-front quark model and QCD. We argue
that this model can be used for an evaluation of the light-cone wave functions
for moderate values of "u", but that it is inapplicable for this purpose in the
region near the ends points u=0,1. We find additional support for a recent
analysis in which it was claimed that the twist-two pion wave function attains
its asymptotic form. The asymptotic twist-four two-particle wave function is
also in good agreement with the light-front quark model.Comment: 11 pages and 2 PS-figures in one gz-compressed .tar file. Minor
chang
Extracting forward strong amplitudes from elastic differential cross sections
The feasibility of a model-independent extraction of the forward strong
amplitude from elastic nuclear cross section data in the Coulomb-nuclear
interference region is assessed for and scattering at intermediate
energies. Theoretically-generated "data" are analyzed to provide criteria for
optimally designing experiments to measure these amplitudes, whose energy
dependence (particularly that of the real parts) is needed for disentangling
various sources of medium modifications of the projectile-nucleon interaction.
The issues considered include determining the angular region over which to make
the measurements, the role of the most forward angles measured, and the effects
of statistical and systematic errors. We find that there is a region near the
forward direction where Coulomb-nuclear interference allows reliable extraction
of the strong forward amplitude for both pions and the from .3 to 1
GeV/c.Comment: 16 pages plus 12 separate postscript figure
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