Experiment 89-044
Experiment 97-011
This experiment was originally approved but was taken off the books
after the jeopardy period. The aim of this experiment was to study high
momentum components in 3,4He measuring both the two body and
multi particle breakup at Q2 = 2,3 (GeV/c)2 and x
> 1. Absorption of a virtual photon on a pair of nucleons should produce
a distinctive ridge in the spectral function when plotted against Emiss
vs Pmiss . The existence of this ridge in data taken earlier
at Saclay for 4He(e,e'p)X was taken as evidence for NN correlations.
Cross sections in parallel kinematics for the -y configuration were to
be measured for both nuclei at 0.3 and 0.45 GeV/c in missing momentum.
A separation of the longitudinal and transverse structure functions in
3He(e,e'p) at Q2 = 2 (GeV/c)2 ,
y = -0.3 GeV/c and x = 1.61, was also proposed. E97011 proposed kinematic
settings so that the kinetic energy of the proton in the triton's
rest frame varied between 0.33 GeV and 0.86 GeV. The kinematics were chosen
so that meson exchange currents and final state interactions should be
minimized. No separations of response functions for the 4He(e,e'p)X
reaction were proposed, in contrast to the present proposal. There is an
overlap in the physics interest in part III of the current proposal where
parallel kinematics in both +y and -y configurations are proposed as a
means of disentangling FSI effects from intrinsic high momentum components
in the nuclear ground state. Continuum cross sections will need to be measured
in both proposals.
Experiment 97-111
Data collection for this approved experiment was completed in Fall,
2000. The aim of this proposal was to measure cross sections for the 4He(e,e'p)3H
reaction in a range of missing momenta which spanned the theoretically
predicted minimum at pmiss = 0.425 GeV/c. The depth of the minimum
in the cross section reflects the minimum in the spectral function for
the triton ground state transition. The minimum is expected to be clearly
seen if the Plane Wave Impulse Approximation is valid. Meson exchange currents
and final state interactions tend to fill the minimum in the cross section.
E97-111 was performed for two settings of constant Q-w
which gave a kinetic energy of the proton in the triton's rest frame of
0.345 GeV. In the proposed experiment for perpendicular kinematics we will
maintain a kinetic energy of the proton in the triton's rest frame of 1.08
GeV. At this higher energy the final state interactions will be treated
using the generalized Glauber approximation, rather than by an optical
potential. E97-111 also measured in parallel kinematics for the positive
y configuration ( cos(thqx) = -1.) in two settings. The
proton's kinetic energy in the triton's rest frame varied from 0.77 GeV
to 1.86 GeV in this (E97-111) experiment. Missing momenta to 0.5
GeV/c were investigated. In the proposed experiment for parallel kinematics
we will, again, maintain a kinetic energy of the proton in the triton's
rest frame of 1.08 GeV. No separations in response functions were attempted
in E97-111, whereas this is a goal of the current proposal.