New parton distributions from large-x and low-Q^2 data

TL;DR

This paper presents a new global fit of parton distribution functions at high x and low Q^2, incorporating broader data and corrections, leading to a more accurate understanding of the d-quark distribution at large x.

Contribution

It introduces a comprehensive NLO fit including target mass, higher twist, and nuclear corrections, improving the modeling of parton distributions at large x.

Findings

The d-quark distribution at large x is softer than previous estimates.

Parton distributions are stable under TMC model variations when higher twist effects are included.

Including more data at high x improves the accuracy of parton distribution functions.

Abstract

We report results of a new global next-to-leading order fit of parton distribution functions in which cuts on W and Q are relaxed, thereby including more data at high values of x. Effects of target mass corrections (TMCs), higher twist contributions, and nuclear corrections for deuterium data are significant in the large-x region. The leading twist parton distributions are found to be stable to TMC model variations as long as higher twist contributions are also included. The behavior of the d quark as x-->1 is particularly sensitive to the deuterium corrections, and using realistic nuclear smearing models the d-quark distribution at large x is found to be softer than in previous fits performed with more restrictive cuts.