CLAS Physics Database

A comparison of forward and backward pp pair knockout in 3He(e, e'pp)n

Spokespersons
H.Baghdasaryan, L.B.Weinstein, J.M.Laget
Abstract
Measuring nucleon-nucleon short range correlations (SRCs) has been a goal of the nuclear physics community for many years. They are an important part of the nuclear wave function, accounting for almost all of the high-momentum strength. They are closely related to the EMC effect. While their overall probability has been measured, measuring their momentum distributions is more difficult. In order to determine the best configuration for studying SRC momentum distributions, we measured the 3He(e,e'pp)n reaction, looking at events with high-momentum protons (pp > 0.35 GeV/c) and a low-momentum neutron (pn < 0.2 GeV/c). We examined two angular configurations: either both protons emitted forward or one proton emitted forward and one backward (with respect to the momentum transfer, q). The measured relative momentum distribution of the events with one forward and one backward proton was much closer to the calculated initial-state pp relative momentum distribution, indicating that this is the preferred configuration for measuring SRC.
Publications
  1. H. Baghdasaryan, L. B. Weinstein, J. M. Laget, and CLAS Collaboration Comparison of forward and backward pp pair knockout in 3He(e,e`pp)n // PHYSICAL REVIEW C 85, 064318 (2012)
  2. H. Baghdasaryan, L.B. Weinstein, J.M. Laget, and CLAS Collaboration Tensor Correlations Measured in 3He(e,e'pp)n // PRL 105, 222501 (2010)
Quantities
dσ/dPrel,pn dσ/dPtot,pn dσ/dPrel,pp dσ/dPtot,pp

Measurements

ID Quantity Beam Target Final state Q2min,
GeV2
Q2max,
GeV2
Wmin,
GeV
Wmax,
GeV
E49M1 dσ/dPrel,pn e 3He ppn 0.8 4.9 0.3 3.9
E49M2 dσ/dPtot,pn e 3He ppn 0.8 4.9 0.3 3.9
E49M3 dσ/dPrel,pp e 3He ppn 0.8 4.9 0.3 3.9
E49M4 dσ/dPtot,pp e 3He ppn 0.8 4.9 0.3 3.9