Review of Brookhaven nuclear transparency measurements in (e?‘?,2e?‘?) reactions at large $Q^{2}$

摘要

In this contribution we summarize the results of two experiments to measure the transparency of nuclei in the (e?‘?, 2e?‘?) quasi-elastic scattering process near 90?° in the $pp$ center-of-mass. The incident momenta went from 6 to 14.4 GeV/c, corresponding to 4.8 e?‘?2 12.7 (GeV/c)2. First, we describe the measurements with the newer experiment, E850, which has more complete kinematic de???nition of quasi-elastic events. E850 covers a larger range of incident momenta, and thus provides more information regarding the nature of the unexpected fall in the transparency above 9 GeV/c. Second, we review the techniques used in an earlier experiment, E834, and show that the two experiments are consistent for the carbon data. We use the transparencies measured in the ???ve nuclei from Li to Pb to set limits on the rate of expansion for protons involved in quasi-elastic scattering at large momentum transfer.