Redetermination of proton sea distributions

TL;DR

This paper presents a detailed analysis of the light flavor sea quark distributions in the proton using NNLO global fits to HERA and ATLAS data, revealing an asymmetry between anti-up and anti-down quarks and reevaluating the Gottfried Sum Rule.

Contribution

It provides new insights into proton sea quark distributions by combining HERA and ATLAS data, highlighting an asymmetry and revising the Gottfried Sum Rule value.

Findings

Anti-up quark distribution exceeds anti-down in (10^{-2}, 1) range.

Reevaluation of the Gottfried Sum Rule shows a surprising deviation from previous measurements.

Asymmetry observed in both HERAshape and ATLASshape analyses.

Abstract

The shapes of light flavor sea quark distributions of the proton are examined directly from two rounds of NNLO global analysis of HERA $e^{\pm}p$ deep inelastic scattering cross section measurements, termed as HERAshape and the ATLAS measurement of $W^{\pm}/Z$ production from $pp$ collision at $\sqrt{s}$ = 7 TeV, termed as ATLASshape. An asymmetric distribution between anti-up ($\ubar$) quark and anti-down ($\dbar$) quark is found in both analysis, showing that the anti-up quark distribution exceeds over anti-down quark distribution in the momentum fraction range $x\in(10^{-2}, 1)$ of these partons. The Gottfried Sum Rule is reevaluated from these extracted parton distribution functions and the obtained value differs surprisingly from that of the NMC and the NuSea Collaborations.