Probing the Deuteron at Very Large Internal Momenta

Abstract

${}^2\mathrm{H}(e,e^{\prime }p)n$ cross sections have been measured at 4-momentum transfers of $Q^2=4.5\pm 0.5$ (GeV/c)${}^2$ over a range of neutron recoil momenta, $p_{\mathrm{r}}$, reaching up to $\sim 1.0$ GeV/c. The data were obtained at fixed neutron recoil angles ${\theta }_{nq}=35^{\circ }$, $45^{\circ }$ and $75^{\circ }$ with respect to the 3-momentum transfer $\vec{q}$. The new data agree well with previous data which reached $p_{\mathrm{r}}\sim 500$ MeV/c. At ${\theta }_{nq}=35^{\circ }$ and $45^{\circ }$, final state interactions (FSI), meson exchange currents (MEC) and isobar currents (IC) are suppressed and the plane wave impulse approximation (PWIA) provides the dominant cross section contribution. The new data are compared to recent theoretical calculations, where we observe a significant discrepancy for missing momenta $p_{\mathrm{r}}>700$ MeV/c.

main article: 6 pages, 2 figures | supplemental material: 7 pages, 13 figures | numerical tables of cross sections for data and theory are provided as ancillary material | This version has minor additions in the concluding paragraph to address the light-cone / EFT formalisms in the context of this experiment. The supplemental materials have new Fig. 10, and modified Fig. 9