New Measurements of High-Momentum Nucleons and Short-Range Structures in Nuclei

We present new measurements of electron scattering from high-momentum nucleons in nuclei. These data allow an improved determination of the strength of two-nucleon correlations for several nuclei, including light nuclei where clustering effects can, for the first time, be examined. The data also include the kinematic region where three-nucleon correlations are expected to dominate.

Figure 1

Extracted deuteron momentum distribution (points) and calculations (curves) using three different $N\mathrm{\text{−}}N$ potentials [39, 40, 41]. Note that the Paris and Av14 calculations are nearly indistinguishable on this scale.

Figure 2

Pernucleon cross section ratios vs $x$ at ${\theta }_e=18°$.

Figure 3

The ${}^4\mathrm{He}/{}^3\mathrm{He}$ ratios from E02-019 ($Q^2\approx 2.9{\mathrm{GeV}}^2$) and CLAS ($⟨Q^2⟩\approx 1.6{\mathrm{GeV}}^2$); errors are combined statistical and systematic uncertainties. For $x>2.2$, the uncertainties in the ${}^3\mathrm{He}$ cross section are large enough that a one-sigma variation of these results yields an asymmetric error band in the ratio. The error bars shown for this region represent the central 68% confidence level region.