Tagged spectator DIS on a polarized spin-1 target

TL;DR

This paper explores semi-inclusive deep-inelastic scattering on polarized deuterons with spectator proton detection, proposing methods to extract free neutron structure functions at future Electron-Ion Colliders.

Contribution

It develops a theoretical framework for tagged DIS on polarized spin-1 targets and introduces a method to extract neutron structure functions via on-shell extrapolation.

Findings

Derived the semi-inclusive DIS cross section structure for polarized spin-1 targets.

Demonstrated the feasibility of extracting neutron spin structure function g_{1n} using proton tagging.

Provided a practical approach for future measurements at EICs.

Abstract

We discuss the process of deep-inelastic electron scattering (DIS) on the polarized deuteron with detection of a nucleon in the nuclear fragmentation region ("spectator tagging"). We cover (a) the general structure of the semi-inclusive DIS cross section on a spin-1 target; (b) the tagged structure functions in the impulse approximation, where deuteron structure is described by the $NN$ light-front wave function; (c) the extraction of free neutron structure through on-shell extrapolation in the recoil proton momentum. As an application we consider the extraction of the neutron spin structure function $g_{1n}$ through polarized electron scattering on the longitudinally polarized deuteron with proton tagging and on-shell extrapolation. Such measurements would be possible at an Electron-Ion Collider (EIC) with polarized deuteron beams and forward proton detectors.