  We summarize the results of two experimental programs at the Alternating
Gradient Synchrotron of BNL to measure the nuclear transparency of nuclei
measured in the A(p,2p) quasielastic scattering process near 90 Deg .in the pp
center of mass. The incident momenta varied from 5.9 to 14.4 GeV/c,
corresponding to 4.8 < Q^2 < 12.7 (GeV/c)^2. First, we describe the
measurements with the newer experiment, E850, which had more complete kinematic
definition of quasielastic events. In E850 the angular dependence of the
nuclear transparency near 90 Deg. c.m., and the nuclear transparency for
deuterons was studied. Second, we review the techniques used in an earlier
experiment, E834, and show that the two experiments are consistent for the
Carbon data. E834 also determines the nuclear transparencies for Li, Al, Cu,
and Pb nuclei as well as for C. We find for both E850 and E834 that the A(p,2p)
nuclear transparency, unlike that for A(e,e'p) nuclear transparency, is
incompatible with a constant value versus energy as predicted by Glauber
calculations. The A(p,2p) nuclear transparency for C and Al increases by a
factor of two between 5.9 and 9.5 GeV/c incident proton momentum. At its peak
the A(p,2p) nuclear transparency is about 80% of the constant A(e,e'p) nuclear
transparency. Then the nuclear transparency falls back to the Glauber level
again. This oscillating behavior is generally interpreted as an interplay
between two components of the pN scattering amplitude; one short ranged and
perturbative, and the other long ranged and strongly absorbed in the nuclear
medium. We suggest a number of experiments for further studies of nuclear
transparency effects.
