We report the first measurement of the(e,e′p)reaction cross-section ratios for Helium-3 (He3), Tritium (H3), and Deuterium (d). The measurement covered a missing momentum range of40≤pmiss≤550MeV/c, at large momentum transfer (?Q2?≈1.9(GeV/c)2) andxB>1, which minimized contributions from non quasi-elastic (QE) reaction mechanisms. The data is compared with plane-wave impulse approximation (PWIA) calculations using realistic spectral functions and momentum distributions. The measured and PWIA-calculated cross-section ratios forHe3/dandH3/dextend to just above the typical nucleon Fermi-momentum (kF≈250MeV/c) and differ from each other by～20%, while forHe3/H3they agree within the measurement accuracy of about 3%. At momenta abovekF, the measuredHe3/H3ratios differ from the calculation by20%?50%. Final state interaction (FSI) calculations using the generalized Eikonal Approximation indicate that FSI should change theHe3/H3cross-section ratio for this measurement by less than 5%. If these calculations are correct, then the differences at large missing momenta between theHe3/H3experimental and calculated ratios could be due to the underlyingNNinteraction, and thus could provide new constraints on the previously loosely-constrained short-distance parts of theNNinteraction.
展开▼
