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

Abstract

We present a precise measurement of double-polarization asymmetries in the ${}^3\overrightarrow{\mathrm{He}}(\vec{\mathrm{e}},{\mathrm{e}}^{\prime }\mathrm{d})$ 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 $\ddot{I}‰$, 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.

6 pages, 4 figures, accepted for publication at Phys. Rev. Lett