405 research outputs found
Factorization Breaking of for polarized deuteron targets in a relativistic framework
We discuss the possible factorization of the tensor asymmetry
measured for polarized deuteron targets within a relativistic framework. We
define a reduced asymmetry and find that factorization holds only in plane wave
impulse approximation and if p-waves are neglected. Our numerical results show
a strong factorization breaking once final state interactions are included. We
also compare the d-wave content of the wave functions with the size of the
factored, reduced asymmetry and find that there is no systematic relationship
of this quantity to the d-wave probability of the various wave functions
Quark-Hadron Duality
Quark-hadron duality and its potential applications are discussed. We focus
on theoretical efforts to model duality.Comment: Plenary Talk given at Baryons 2002, Newport News, VA, March 200
Lagrangian with off-shell vertices and field redefinitions
Meson exchange diagrams following from a lagrangian with off-shell
meson-nucleon couplings are compared with those generated from conventional
dynamics. The off-shell interactions can be transformed away with the help of a
nucleon field redefinition. Contributions to to the - and -potentials
and nonminimal contact e.m. meson-exchange currents are discussed, mostly for
an important case of scalar meson exchange. (pacs 11.10.Lm, 13.75.Cs, 21.30.-x,
24.10.Jv)Comment: 18 pages (Revtex), 4 eps figure
Coincidence charged-current neutrino-induced deuteron disintegration for
Semi-inclusive charge-changing neutrino reactions on targets of heavy water
are investigated with the goal of determining the relative contributions to the
total cross section of deuterium and oxygen in kinematics chosen to emphasize
the former. The study is undertaken for conditions where the typical neutrino
beam energies are in the few GeV region, and hence relativistic modeling is
essential. For this, the previous relativistic approach for the deuteron is
employed, together with a spectral function approach for the case of oxygen.
Upon optimizing the kinematics of the final-state particles assumed to be
detected (typically a muon and a proton) it is shown that the oxygen
contribution to the total cross section is suppressed by roughly an order of
magnitude compared with the deuterium cross section, thereby confirming that
CC studies of heavy water can effectively yield the cross sections for
deuterium, with acceptable backgrounds from oxygen. This opens the possibility
of using deuterium to determine the incident neutrino flux distribution, to
have it serve as a target for which the nuclear structure issues are minimal,
and possibly to use deuterium to provide improved knowledge of specific aspects
of hadronic structure, such as to explore the momentum transfer dependence of
the isovector axial-vector form factor of the nucleon
Quark-Hadron Duality in Structure Functions
While quark-hadron duality is well-established experimentally, the current
theoretical understanding of this important phenomenon is quite limited. To
expose the essential features of the dynamics behind duality, we use a simple
model in which the hadronic spectrum is dominated by narrow resonances made of
valence quarks. We qualitatively reproduce the features of duality as seen in
electron scattering data within our model. We show that in order to observe
duality, it is essential to use the appropriate scaling variable and scaling
function. In addition to its great intrinsic interest in connecting the
quark-gluon and hadronic pictures, an understanding of quark-hadron duality
could lead to important benefits in extending the applicability of scaling into
previously inaccessible regions.Comment: 16 pages, 4 figures; minor typos correcte
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