Target mass corrections in lepton--nucleus DIS: theory and applications to nuclear PDFs

TL;DR

This paper develops a formalism for target mass corrections in deep-inelastic scattering on nuclear targets, emphasizing a nucleus-intrinsic approach and providing practical, approximately target-independent formulas for various nuclear environments.

Contribution

It introduces a nucleus-focused TMC formalism using re-scaled variables, avoiding nucleon-based pictures, and offers a universal fit applicable to multiple nuclear targets.

Findings

Nuclear TMCs are approximately target-independent using re-scaled variables.

A single-parameter fit accurately reproduces full TMC computations.

Numerical predictions are provided for current and future DIS facilities.

Abstract

Motivated by the wide range of kinematics covered by current and planned deep-inelastic scattering (DIS) facilities, we revisit the formalism, practical implementation, and numerical impact of target mass corrections (TMCs) for DIS on unpolarized nuclear targets. An important aspect is that we only use nuclear and later partonic degrees of freedom, carefully avoiding a picture of the nucleus in terms of nucleons. After establishing that formulae used for individual nucleon targets $(p,n)$, derived in the Operator Product Expansion (OPE) formalism, are indeed applicable to nuclear targets, we rewrite expressions for nuclear TMCs in terms of \mbox{re-scaled} (or averaged) kinematic variables. As a consequence, we find a representation for nuclear TMCs that is approximately independent of the nuclear target. We go on to construct a single-parameter fit for all nuclear targets that is in good numerical agreement with full computations of TMCs. We discuss in detail qualitative and quantitative differences between nuclear TMCs built in the OPE and the parton model formalisms, as well as give numerical predictions for current and future facilities.