We present an improved determination of the strange quark and anti-quark parton distribution functions of the proton by means of a global QCD analysis that takes into account a comprehensive set of strangeness-sensitive measurements: charm-tagged cross sections for fixed-target neutrino- nucleus deep-inelastic scattering, and cross sections for inclusive gauge-boson production and W- boson production in association with light jets or charm quarks at hadron colliders. Our analysis is accurate to next-to-next-to-leading order in perturbative QCD and specifically includes charm-quark mass corrections to neutrino-nucleus structure functions. We find that a good overall description of the input dataset can be achieved and that a moderately suppressed strangeness is strongly favored by the global analysis.

Paper: https://arxiv.org/abs/2009.00014


Fitted charm: NNPDF31_nnlo_as_0118_strange_nomad_Enu

Perturbative charm: NNPDF31_nnlo_as_0118_strange_pch_nomad_Enu