Abstract for JLAB Technical Note 01-047  

The study of short-range nucleon-nucleon correlations has a long history. The idea was first invoked in order to explain the large photo-induced proton yield on nuclei [1]. Such studies have become more feasible in recent years due to the availability of CW photon and electron beams at LEGS, NIKHEF, Mainz, and JLab [2]. Several dedicated two nucleon, 2N, knock-out experiments in photo- and electro-production have been completed recently, for a review, see reference [3]. In order to emphasize various aspects of the physics, kinematics must be chosen to permit measurements in the Q2 range up to several (GeV/c)2. Such difficult measurements are only possible with beam energies and intensities available at JLab. In Hall A at JLab, luminosities up to 5.1038cm-2/s are available, required for the measurement of low cross sections at high Q2. However, the usable luminosity depends on the target thickness, background, detector parameters, and other details of the proposed experiment. In Hall B at JLab, where the CLAS detector subtends a large phase space, the available luminosity is 1.1034cm-1/s. The data with CLAS have already been taken, but must be summed over several kinematics parameters including Q2 [4] in order to provide sufficient statistics.

In preparation for 2N knock-out experiments in Hall A, a Monte Carlo simulation code describing particle yields for protons, neutrons, pions, electron, gammas, etc. was used [5] and several experimental tests were performed to test the calculations [6]. The first study of particle flow was actually motivated by a Compton scattering experiment [7]. More experimental tests were performed to study and optimize conditions for the 2N knock-out experiments. Recently, an experiment was performed to test the detection of the (e,e'pn) process in Hall A at high luminosity [8]. A critical parameter in determining effective rates in an experiment is the detector acceptance. A large momentum and angular acceptance magnetic dipole spectrometer with moderate momentum resolution was developed and used at NIKHEF [9]. Modification of the detector system and electronics will allow to use BigBite at luminosities up to 1.1038cm-2/s [10]. We discuss the plans to upgrade BigBite as a new tool for correlation studies. The high luminosity and simultaneous multi-particle detection capability of BigBite provide an opportunity to detect two correlated protons at small relative momentum. This physics was addressed in proposal [11], but for a limited range of kinematics. Here we present the results of the above studies.


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