We show that color transparency produces either strong nuclear shadowing or antishadowing, depending on the specific (semi)exclusive photoproduction reaction off nuclei. Neither coherent nor ...quasielastic diffractive photoproduction of charmonium on nuclei measures the charmonium-nucleon total cross section and the vector-dominance-model interpretation of nuclear photoproduction data cannot be applied. We relate the {ital A} dependence of the coherent and quasielastic photoproduction cross sections and derive the energy dependence of shadowing. The results are in good agreement with the New Muon Collaboration data.
The cross section for inclusive electron scattering by nuclear matter is calculated at high momentum transfers using a microscopic spectral function, and compared with that extrapolated from data on ...laboratory nuclei. It is found that the cross section obtained with the plane-wave impulse approximation is close to the observed data at large values of the energy loss, but too small at low values. In this regime final-state interactions are important; after including their effects theory and data are in fair agreement. It is necessary to treat nucleon-nucleon correlations consistently in estimating the final-state interactions. The effects of possible time dependence of the nucleon-nucleon cross section, giving rise to nuclear transparency, are also investigated. The {ital y} scaling of the response function is discussed to further elucidate the role of final-state interactions.
Polarization observables in the (4)He(e-->,e'p-->)(3)H reaction are calculated using accurate three- and four-nucleon bound-state wave functions, a realistic model for the nuclear electromagnetic ...current operator, and a treatment of final-state interactions with an optical potential. In contrast to earlier studies, no significant discrepancies are found between theory and experiment both for the ratio of transverse to longitudinal polarization transfers and for the induced polarization, when free-nucleon electromagnetic form factors are used in the current operator. The present results challenge the current interpretation of the experimental data in terms of medium-modified form factors.
We use multiple scattering theory to evaluate the
Q
2 dependence of the forward-backward asymmetry,
A
z
, of the missing momentum distribution in quasielastic
A(
e,
e′,
p) scattering, which is ...expected to be affected by color transparency. The novel features of our analysis are a consistent treatment of the structure of the ejectile state formed after absorption of the virtual photon by the struck proton and a careful evaluation of the background asymmetry induced by the nonvanishing real part of the proton-nucleon scattering amplitude. We find that the absolute magnitude of
A
z
is dominated by this background at the
Q
2's attainable at the Continuous Electron Beam Accelerator Facility. However, the
Q
2 dependence of the asymmetry is sensitive to the onset of color transparency, whose observation in high precision experiments appears to be feasible, particularly using light targets such as
12C or
16O.
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