Speaker
Description
Quark--hadron duality --- the averaging of resonance-region structure functions to perturbative QCD scaling behavior --- links the hadronic and partonic pictures of the nucleon. We present a high-precision test of this phenomenon in inclusive electron--proton scattering in the nucleon resonance region, reaching $Q^{2}\approx10~\mathrm{GeV}^{2}$, based on recent CLAS12 cross-section measurements at Jefferson Lab. The data, taken with a $10.6$~GeV electron beam, span nine bins in $Q^{2}$ over $2.55 \le Q^{2} \le 10.4~\mathrm{GeV}^{2}$ and cover the full resonance region from pion threshold up to $W\approx2.5~\mathrm{GeV}$. To describe the hadronic response in this kinematic regime, we develop a high-$Q^{2}$ extension of the Argonne National Laboratory--Osaka University (ANL-Osaka) dynamical coupled-channels model, constrained by the measured cross sections and anchored to the original calculation at
$Q_{0}^{2}=2.774~\mathrm{GeV}^{2}$. This enables a phenomenologically constrained longitudinal--transverse decomposition and extraction of the proton structure function $F_{2}(W,Q^{2})$, from which we evaluate $W$-truncated Cornwall--Norton moments $M_{2}(Q^{2})$ for the first, second, and third resonance regions and the high-$W$ region. Comparison with the CJ15 global QCD analysis, including target-mass and higher-twist corrections, shows overall consistency at the cross-section, structure-function, and truncated-moment levels across the range probed, providing quantitative evidence for both local and global duality and extending previous tests to substantially higher $Q^{2}$.