Abstract
We report the results of a Monte Carlo global QCD analysis of unpolarized parton distribution functions (PDFs), including for the first time constraints from ratios of to structure functions recently obtained by the MARATHON experiment at Jefferson Lab. Our simultaneous analysis of nucleon PDFs and nuclear effects in and nuclei reveals the first indication for an isovector nuclear EMC effect in light nuclei. We find that while the MARATHON data yield relatively weak constraints on the neutron to proton structure function ratio and on the PDF ratio, they suggest an enhanced nuclear effect on the -quark PDF in the bound proton, questioning the assumptions commonly made in nuclear PDF analyses.
- Received 22 April 2021
- Revised 23 August 2021
- Accepted 28 October 2021
DOI:https://doi.org/10.1103/PhysRevLett.127.242001
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.
Published by the American Physical Society