Valence Quark Ratio in the Proton
Zhu-Fang Cui, Fei Gao, Daniele Binosi, Lei Chang, Craig D. Roberts, Sebastian M. Schmidt
Abstract
Beginning with precise data on the ratio of structure functions in deep inelastic scattering (DIS) from 3 He and 3 H, collected on the domain 0.19 ≤ x B ≤ 0.83, where x B is the Bjorken scaling variable, we employ a robust method for extrapolating such data to arrive at a model-independent result for the x B = 1 value of the ratio of neutron and proton structure functions. Combining this with information obtained in analyses of DIS from nuclei, corrected for target-structure dependence, we arrive at a prediction for the proton valence-quark ratio: d ν / u νq | x B → 1 = 0.230 (57). Requiring consistency with this result presents a challenge to many descriptions of proton structure.