A new global analysis of deep inelastic scattering data

TL;DR

The paper presents a comprehensive global NLO QCD analysis of deep inelastic scattering that simultaneously fits neutrino/antineutrino cross sections, charged-lepton DIS, and Drell-Yan data. It uses a Fixed Flavour Scheme for charm and incorporates detailed bin-centre and radiative corrections, plus robust nuclear corrections, to extract parton distribution functions with an emphasis on a precisely determined strange sea. The authors demonstrate excellent overall agreement with diverse data sets and reveal evidence for a potential s ≠ sbar asymmetry, while outlining future work to extract alpha_s and compare heavy-quark schemes. This work advances the reliability and precision of global PDF determinations in the DIS regime and strengthens constraints on the nucleon’s flavor structure, including the strange sector.

Abstract

A new QCD analysis of Deep Inelastic Scattering (DIS) data is presented. All available neutrino and anti-neutrino cross sections are reanalysed and included in the fit, along with charged-lepton DIS and Drell-Yan data. A massive factorisation scheme is used to describe the charm component of the structure functions. Next-to-leading order parton distribution functions are provided. In particular, the strange sea density is determined with a higher accuracy with respect to other global fits.

Figures (18)

• Figure 1: a) Correction factor applied to CDHSW $\nu Fe$ data of the 111 GeV beam energy sample, as a function of $y$ for various $x$ bins; b) same as a) but for CDHSW $\bar{\nu} Fe$ data; c) electroweak radiative correction factor $\delta_{rad}\equiv (d^2\tilde{\sigma}^{B+R}/dxdy)/(d^2\tilde{\sigma}^{B}/dxdy)-1$ in percent for CDHSW $\nu Fe$; d) same as c) but for CDHSW $\bar{\nu} Fe$.
• Figure 2: Total cross sections of $\nu Fe$ (top) and $\bar{\nu} Fe$ (bottom) from CDHSW. The shaded areas are the one-standard-deviation error bands corresponding to the linear fits described in section \ref{['CDHSW-measurements']}. The curves are the results of fit1. The error bars correspond to the quadratic sum of statistical and systematic errors.
• Figure 3: $Fe/D$ structure function ratio. The full line is the result of a second order polynomial fit and the shaded area is the corresponding one-standard-deviation error band (see section \ref{['Nuclear-targets']}). The error bars correspond to the quadratic sum of statistical and systematic errors.
• Figure 4: Corrections applied to Iron target data: a) isoscalarity corrections; b) nuclear and isoscalarity corrections.
• Figure 5: The parton distribution functions of fit1, with their error bands, compared to the GRV98 (solid line), CTEQ4M (dashed line) and MRST (dotted line) fits. The results of fit1 for $u_v$, $\bar{u}$ and $\bar{d}$ -- hardly visible -- nearly coincide with the MRST and CTEQ4M results.