Comparing proton momentum distributions in A = 2 and 3 nuclei via 2H 3H and 3He (e,e′p) measurements
© 2019 The Author(s) 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 of 40≤pmiss≤550MeV/c, at large momentum transfer (〈Q2〉≈1.9 (GeV/c)2) and xB>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 for He3/d and H3/d extend to just above the typical nucleon Fermi-momentum (kF≈250 MeV/c) and differ from each other by ∼20%, while for He3/H3 they agree within the measurement accuracy of about 3%. At momenta above kF, the measured He3/H3 ratios differ from the calculation by 20%−50%. Final state interaction (FSI) calculations using the generalized Eikonal Approximation indicate that FSI should change the He3/H3 cross-section ratio for this measurement by less than 5%. If these calculations are correct, then the differences at large missing momenta between the He3/H3 experimental and calculated ratios could be due to the underlying NN interaction, and thus could provide new constraints on the previously loosely-constrained short-distance parts of the NN interaction.
Cruz-Torres, R.; Li, S.; Hauenstein, F.; Schmidt, A.; Nguyen, D.; Abrams, D.; Albataineh, H.; Alsalmi, S.; Androic, D.; Aniol, K.; Armstrong, W.; Arrington, J.; Atac, H.; Averett, T.; Ayerbe Gayoso, C.; Bai, X.; Bane, J.; Barcus, S.; Beck, A.; Bellini, V.; Bhatt, H.; Bhetuwal, D.; Biswas, D.; Blyth, D.; Boeglin, W.; Bulumulla, D.; Camsonne, A.; Castellanos, J.; Chen, J. P.; Cohen, E. O.; King, P.; and Roche, J., "Comparing proton momentum distributions in A = 2 and 3 nuclei via 2H 3H and 3He (e,e′p) measurements" (2019). Physics & Astronomy Open Access Publications. 15.