Update of the global fit of PDFs including the low-Q DIS data

TL;DR

This paper presents an updated NNLO QCD global fit of parton distribution functions (PDFs) incorporating low-Q deep inelastic scattering data, improving PDF accuracy and determining the strange quark distribution and higher-twist terms.

Contribution

It provides the first NNLO fit including low-Q DIS data and neutrino-nucleon dimuon production, refining the PDFs and related parameters.

Findings

Good data set consistency with ^2/NDP=1.2

Determined _s(M_Z)=0.1136(exp.)

Identified higher-twist contributions in structure functions

Abstract

We perform the next-to-next-leading-order (NNLO) QCD global fit of PDFs using inclusive charged-lepton and neutrino DIS data down to Q = 1 GeV. We also consider the data on neutrino-nucleon dimuon production, that allows us to disentangle the strange sea distribution. The fit results in \chi^2/NDP = 5150/4338 = 1.2 that demonstrates a good consistency of the data sets used in analysis. The resulting value of \alpha_s(M_Z) = 0.1136+- 0.0007(exp.) is in a good agreement with the previous version of the fit with a more stringent cut on Q. This analysis allows us to improve the accuracy of PDFs. The HT terms of the neutrino-nucleon structure functions F_2 and xF_3 are determined, the former is found to be consistent with one for the charged-leptons if the charge factor is taken into account.