Structure functions for light nuclei

TL;DR

This paper analyzes the nuclear EMC effect in light nuclei, comparing various experimental data sets, addressing normalization issues, and evaluating theoretical models to achieve consistent understanding of nuclear structure functions.

Contribution

It provides a comprehensive comparison of experimental data on light nuclei, identifies normalization discrepancies, and assesses theoretical models including nuclear effects to explain the EMC effect.

Findings

Good agreement between NMC, SLAC E139, and HERMES data.

Normalization offset of about 2% in JLab E03-103 data for heavy nuclei.

After renormalization, data and models show good consistency.

Abstract

We discuss the nuclear EMC effect with particular emphasis on recent data for light nuclei including 2H, 3He, 4He, 9Be, 12C and 14N. In order to verify the consistency of available data, we calculate the \chi^2 deviation between different data sets. We find a good agreement between the results from the NMC, SLAC E139, and HERMES experiments. However, our analysis indicates an overall normalization offset of about 2% in the data from the recent JLab E03-103 experiment with respect to previous data for nuclei heavier than 3He. We also discuss the extraction of the neutron/proton structure function ratio F2n/F2p from the nuclear ratios 3He/2H and 2H/1H. Our analysis shows that the E03-103 data on 3He/2H require a renormalization of about 3% in order to be consistent with the F2n/F2p ratio obtained from the NMC experiment. After such a renormalization, the 3He data from the E03-103 data and HERMES experiments are in a good agreement. Finally, we present a detailed comparison between data and model calculations, which include a description of the nuclear binding, Fermi motion and off-shell corrections to the structure functions of bound proton and neutron, as well as the nuclear pion and shadowing corrections. Overall, a good agreement with the available data for all nuclei is obtained.