Electron–deuteron DIS with spectator tagging at EIC: Development of theoretical framework

W Cosyn,C Weiss,M Sargsian,M Strikman,V Guzey

doi:10.1051/epjconf/201611201022

Abstract

An Electron-Ion Collider (EIC) would enable next-generation measurements of deep-inelastic scattering (DIS) on the deuteron with detection of a forward-moving nucleon (p, n) and measurement of its recoil momentum ("spectator tagging"). Such experiments offer full control of the nuclear configuration during the high-energy process and can be used for precision studies of the neutron's partonic structure and its spin dependence, nuclear modifications of partonic structure, and nuclear shadowing at small x. We review the theoretical description of spectator tagging at EIC energies (light-front nuclear structure, on-shell extrapolation in the recoil nucleon momentum, final-state interactions, diffractive effects at small x) and report about on-going developments.

Highlights

The basic observable is the invariant differential cross section for inclusive deep-inelastic scattering (DIS) on the deuteron with an identified nucleon with recoil momentum pR in the final state (see Fig. 1a): dσ(eD → e NX) dx dQ2 (d3 pR/ER)
The deuteron’s pn wave function is simple and well known from low–energy measurements, including the light–front wave function entering in high–energy processes
Because the deuteron has isospin I = 0, Δ isobars in the wave function are strongly suppressed, so that the deuteron can be treated as a pn system for most of the configurations relevant to deep-inelastic scattering (DIS) [6]

Summary

Introduction

The basic observable is the invariant differential cross section for inclusive DIS on the deuteron with an identified nucleon with recoil momentum pR in the final state (see Fig. 1a): dσ(eD → e NX) dx dQ2 (d3 pR/ER) An essential feature of the impulse approximation is that it captures the leading singularity of the tagged structure function in the invariant momentum transfer between the deuteron and the recoiling nucleon, t ≡ (pD − pR)2 = function(αR, pRT ).

Results

Conclusion