On the Cancellation of Nuclear Effects in the Valence Region

TL;DR

This paper shows that nuclear effects on valence quark structure functions are minimal across various nuclei, indicating a near-cancellation of nuclear modifications in deep-inelastic scattering data.

Contribution

It provides evidence for the cancellation of nuclear modifications in the valence region, supported by analysis of world measurements of cross-section ratios across different nuclei.

Findings

Nuclear modifications to structure functions are minimal near the valence peak.

The isoscalar cross-section ratios are close to unity with high precision.

Results suggest a microscopic cancellation mechanism for nuclear effects.

Abstract

Deep-inelastic $e/\mu$ scattering data off targets ranging from deuterium to lead indicate that the nuclear modifications to the structure functions of bound nucleons are minimal in the kinematic region around the peak of the valence quark distributions. An analysis of world measurements of the isoscalar cross-section ratios $\sigma^A/\sigma^{{}^2\text{H}}$ in the region of $0.25 \leq x \leq 0.35$ shows a remarkable cancellation across all nuclei, with an average value of $0.9985 \pm 0.0022$. We discuss these results and possible interpretations in the context of a microscopic model of nuclear modifications of the structure functions.