Modern Studies of the Deuteron: from the Lab Frame to the Light Front

TL;DR

This paper reviews recent experimental and theoretical advances in probing the deuteron at short distances using high momentum transfer experiments, highlighting the transition to relativistic descriptions and the extraction of light-cone momentum distributions.

Contribution

It presents the first extraction of the deuteron light-cone momentum distribution from experimental data and discusses its significance for understanding QCD effects in bound nucleons.

Findings

Deuteron probed at momenta beyond 300 MeV/c without dominant long-range effects.

Confirmation of the high energy eikonal regime in scattering processes.

First attempt to extract the deuteron light-cone momentum distribution from data.

Abstract

We review the recent progress made in studies of deuteron structure at small internucleon distances. This progress is largely facilitated by the new generation of experiments in deuteron electrodisintegration carried out at unprecedentedly high momentum transfer. The theoretical analysis of these data confirms the onset of the high energy eikonal regime in the scattering process which allows one to separate long range nuclear effects from the effects genuinely related to the short distance structure of the deuteron. Our conclusion is that for the first time the deuteron is probed at relative momenta beyond 300 MeV/c without dominating long range effects. As a result, at these large nucleon momenta the cross section is sensitive to the nuclear dynamics at sub-fermi distances. Due to large internal momenta involved we are dealing with the relativistic bound state that is best described by the light-cone momentum distribution of nucleons in the deuteron. We present the first attempt of extracting the deuteron light-cone momentum distribution function from data and discuss the importance of this quantity for studies of QCD structure of the bound nucleon in deep inelastic scattering off the deuteron. We conclude the review giving an outlook of the next generation of high energy experiments which will extend our reach to much smaller distances in the deuteron.