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

TL;DR

This study measures double-polarization asymmetries in the quasi-elastic breakup of helium-3 to explore its electromagnetic and spin structure, revealing that existing models underestimate the influence of three-body interactions.

Contribution

It provides the first precise measurements of these asymmetries at specific kinematics, challenging current theoretical models of three-body nuclear interactions.

Findings

Measured asymmetries are inconsistent with state-of-the-art calculations.

Adjusting three-body interaction components improves theoretical agreement.

Results suggest the spin-dependent three-body effects are smaller than previously estimated.

Abstract

We report on a precise measurement of double-polarization asymmetries in electron-induced breakup of $^3\mathrm{He}$ proceeding to $\mathrm{pd}$ and $\mathrm{ppn}$ final states, performed in quasi-elastic kinematics at $Q^2 = 0.25\,(\mathrm{GeV}/c)^2$ for missing momenta up to $250\,\mathrm{MeV}/c$. These observables represent highly sensitive tools to investigate the electromagnetic and spin structure of $^3\mathrm{He}$ and the relative importance of two- and three-body effects involved in the breakup reaction dynamics. The measured asymmetries cannot be satisfactorily reproduced by state-of-the-art calculations of $^3\mathrm{He}$ unless their three-body segment is adjusted, indicating that the spin-dependent part of the nuclear interaction governing the three-body breakup process is much smaller than previously thought.