The strangeness content of the proton can only be small

It has recently been claimed that the explicit introduction of a so-called "non-perturbative" contribution to the spin-dependent strange-quark distribution in the proton sea may avoid positivity bounds obtained from very precise data presently available for the corresponding unpolarised distributions. We show that the unusual large-xB behaviour, ∼(1 - x)^5, required for such avoidance is entirely incompatible with that displayed by the existing deep-inelastic neutrino data, ∼(1 - x)^10. Thus we demonstrate the untenability of this scenario for the avoidance of the positivity bound on the magnitude of the strange-quark contribution to the proton-spin sum-rule. Such a bound leads to a marked disagreement between predictions based on the light-cone expansion in perturbative QCD and experimental measurements.