Neutrino scattering bound on intrinsic charm of nucleon

The uudc$\text{c}$ five-quark Fock component of the proton, recently proposed by Brodsky et al., is compatible with the CDHS upper bound on wrong-sign ν → μ⁺ events if the integrated charm probability per nucleon is at the suggested level λ = 0.01. With various realistic assumptions, the CDHS bound may be interpreted as λ < 0.025 with 90% confidence.