Light flavor asymmetry of nucleon sea

TL;DR

This paper calculates the light flavor antiquark distributions in the nucleon sea using an effective chiral quark model, successfully matching some experimental results and highlighting discrepancies at large x, suggesting further precise measurements.

Contribution

It introduces a calculation of nucleon sea antiquark distributions incorporating flavor-symmetric and nuclear effects, aligning with some experimental data and proposing improved measurement methods.

Findings

Calculated Drell-Yan cross section ratios match experimental data.

Results agree with measured (x)-ar(x) distributions.

Discrepancies found in (x)/ar(x) at large x, prompting further experiments.

Abstract

The light flavor antiquark distributions of the nucleon sea are calculated in the effective chiral quark model and compared with experimental results. The contributions of the flavor-symmetric sea-quark distributions and the nuclear EMC effect are taken into account to obtain the ratio of Drell-Yan cross sections $\sigma^{\mathrm{pD}}/2\sigma^{\mathrm{pp}}$, which can match well with the results measured in the FermiLab E866/NuSea experiment. The calculated results also match the measured $\bar{d}(x)-\bar{u}(x)$ from different experiments, but unmatch the behavior of $\bar{d}(x)/\bar{u}(x)$ derived indirectly from the measurable quantity $\sigma^{\mathrm{pD}}/2\sigma^{\mathrm{pp}}$ by the FermiLab E866/NuSea Collaboration at large $x$. We suggest to measure again $\bar{d}(x)/\bar{u}(x)$ at large $x$ from precision experiments with careful experimental data treatment. We also propose an alternative procedure for experimental data treatment.