Determination of Strange Sea Distributions from Neutrino-Nucleon Deep Inelastic Scattering

We present an analysis of the nucleon strange sea extracted from a global Parton Distribution Function fit including the neutrino and anti-neutrino dimuon data by the CCFR and NuTeV collaborations, the inclusive charged lepton-nucleon Deep Inelastic Scattering and Drell-Yan data. The (anti-)neutrino induced dimuon analysis is constrained by the semi-leptonic charmed-hadron branching ratio $B_\mu=(8.8\pm0.5)%$, determined from the inclusive charmed hadron measurements performed by the FNAL-E531 and CHORUS neutrino emulsion experiments. Our analysis yields a strange sea suppression factor $\kappa(Q^2=20{\rm GeV}^2)=0.62\pm 0.04$, the most precise value available, an $x$-distribution of total strange sea that is slightly softer than the non-strange sea, and an asymmetry between strange and anti-strange quark distributions consistent with zero (integrated over $x$ it is equal to $0.0013 \pm 0.0009$ at $Q^2=20{\rm GeV}^2$).