On the Interplay of Nuclear and Higher-Twist Corrections in Nuclear Structure Functions

TL;DR

This paper presents a comprehensive QCD analysis of nuclear structure functions, incorporating data from various nuclear targets to simultaneously extract parton distributions, higher-twist effects, and off-shell corrections, revealing their interplay and consistency with experimental ratios.

Contribution

It introduces a unified analysis framework that determines nuclear modifications, higher-twist terms, and off-shell effects simultaneously, providing new insights into nuclear structure functions and their ratios.

Findings

Data on nuclear cross section ratios agree with a single isoscalar off-shell function.

Predictions for neutron-to-proton structure function ratios are provided.

Results inform future measurements of the EMC effect with parity-violating DIS.

Abstract

We discuss results from our global QCD analyses including nuclear data off deuterium from various measurements, as well as off $\htri$ and $\hetri$ targets from the \mara{} experiment. We simultaneously determine the parton distribution functions of the proton, the higher-twist terms, and the nucleon off-shell correction functions responsible for the modifications of the partonic structure in bound protons and neutrons. In particular, we study the neutron-proton asymmetry of the off-shell correction and its interplay with the treatment of the higher-twist terms. We observe that the data on the $\hetri/\htri, \hetri/\hdeu$, and $\htri/\hdeu$ cross section ratio are in good agreement with the predictions based on a single isoscalar off-shell function. We provide the corresponding predictions on the ratio $F_2^n/F_2^p$, on the $d$ and $u$ quark distributions in the proton and in the $\htri$ and $\hetri$ nuclei, as well as for future measurements of the EMC effect with parity-violating Deep Inelastic Scattering (DIS).