Reinterpretation of proton strangeness between ATLAS and CMS measurements

TL;DR

This study reanalyzes proton strange quark distributions using QCD fits to HERA and LHC data, revealing agreement at small x and tension at large x, with an observed x-dependent strange-to-non-strange ratio.

Contribution

It provides a unified reinterpretation of ATLAS and CMS measurements, clarifying the proton strangeness distribution across different x ranges.

Findings

Agreement between CMS W+ charm and ATLAS W/Z data at small x

Tension between datasets at large x resolved when combined

Strange quark distribution is enhanced at small x and suppressed at large x

Abstract

We reexamine the shapes of the strange quark parton distribution functions (PDFs) of the proton by means of quantum chromodynamics (QCD) analysis of {\hera} deep inelastic scattering cross section measurement at DESY, and inclusive gauge boson production and $W$ boson production associated with a charm quark from LHC at CERN. We find that there is an overall agreement on the strange quark distributions obtained from CMS $W$ + charm and ATLAS $W/Z$ data at the parton momentum fraction range $x \lesssim 10^{-2}$. Meanwhile, there is also a strong tension between these data towards large $x$. We find that this tension fades away if the ATLAS measurement of $W/Z$ production is analyzed together with the ATLAS $W$ + charm data. The $W/Z$ and $W$ + charm data both from ATLAS and CMS experiments agree that the proton strangeness is enhanced towards small momentum fraction $x$ and is smoothly suppressed at large $x$. Furthermore, a strong $x$ dependence of the strange-to-non-strange parton ratio $R_s(x,Q^2)$ is observed.