High-energy deep-inelastic scattering and analytic model of the virtual Compton amplitude

Abstract

Recent experimental data from Fermilab on the large-$\ensuremath{\omega}$ behavior and scale-invariance breaking of the nucleon structure function $\ensuremath{\nu}{W}_{2}(\ensuremath{\omega},{Q}^{2})$ measured over a wide range of $\ensuremath{\omega}$ and ${Q}^{2}$ covering $1\ensuremath{\lesssim}\ensuremath{\omega}\ensuremath{\le}1000$, $0.2\ensuremath{\le}{Q}^{2}\ensuremath{\le}50$ ${\mathrm{GeV}}^{2}$ are in surprisingly good agreement with the absolute prediction of an analytic model of the virtual (forward) Compton amplitude proposed recently by the authors. On the basis of this agreement we conclude that (i) the observed decrease of $\ensuremath{\nu}{W}_{2}(\ensuremath{\omega},{Q}^{2})$ at large $\ensuremath{\omega}$ is consistent with diffractive behavior of the nucleon function ${F}_{2}(\ensuremath{\omega})$, (ii) the decrease results most probably from the kinematic constraint, $limit of\text{}\ensuremath{\nu}{W}_{2}(\ensuremath{\omega},{Q}^{2})\text{as}{Q}^{2}\ensuremath{\rightarrow}0=0$ valid for all $\ensuremath{\omega}g{\ensuremath{\omega}}_{\mathrm{threshold}}$ (iii) the observed pattern of deviation is consistent with precocious scaling around ${Q}^{2}\ensuremath{\simeq}2$ ${\mathrm{GeV}}^{2}$, and (iv) there is a $\frac{1}{{Q}^{2}}$ approach to scale invariance. The predicted results of the model for the Callan-Gross and the Gottfried sum rules are in very good agreement with the predictions of the Kuti-Weisskopf model. We also present and discuss the moments of the structure function.