Measurement of double-polarization asymmetries in the quasi-elastic $^3\vec{\mathrm{He}}(\vec{\mathrm{e}},\mathrm{e}'\mathrm{d})$ process

TL;DR

This study measures double-polarization asymmetries in a helium-3 electron scattering process to test and challenge existing theoretical models of nuclear dynamics, revealing areas needing further refinement.

Contribution

It provides the first precise experimental data on polarization asymmetries in the $^3$He(e,e'd) reaction, highlighting discrepancies with current theoretical calculations.

Findings

Asymmetries agree with models near the quasi-elastic peak but show systematic offsets.

Discrepancies increase outside the quasi-elastic region, indicating model deficiencies.

Results suggest the need for improved treatment of two- and three-body nuclear interactions.

Abstract

We present a precise measurement of double-polarization asymmetries in the $^3\vec{\mathrm{He}}(\vec{\mathrm{e}},\mathrm{e}'\mathrm{d})$ reaction. This particular process is a uniquely sensitive probe of hadron dynamics in $^3\mathrm{He}$ and the structure of the underlying electromagnetic currents. The measurements have been performed in and around quasi-elastic kinematics at $Q^2 = 0.25\,(\mathrm{GeV}/c)^2$ for missing momenta up to $270\,\mathrm{MeV}/c$. The asymmetries are in fair agreement with the state-of-the-art calculations in terms of their functional dependencies on $p_\mathrm{m}$ and $\omega$, but are systematically offset. Beyond the region of the quasi-elastic peak, the discrepancies become even more pronounced. Thus, our measurements have been able to reveal deficiencies in the most sophisticated calculations of the three-body nuclear system, and indicate that further refinement in the treatment of their two- and/or three-body dynamics is required.