| Popis: |
In this paper, we explore the properties of the Ellis-Jaffe Sum Rule (EJSR) in detail, employing the Principle of Maximum Conformality (PMC) approach to address its perturbative QCD contribution including next-to-next-to-next-to-leading order ($\rm N^{3}LO$) QCD corrections. Using the PMC, we attain a precise perturbative QCD approximate for the EJSR, without the conventional ambiguity associated with the renormalization scale. Given the presence of the $\alpha_s$ Landau pole near the asymptotic scale, we also utilize the low-energy $\alpha_s$ model based on the analytic perturbative theory (APT) to recalibrate the EJSR behavior in the infrared region. By combining the PMC approach with the low-energy APT model, we achieved theoretical predictions of EJSR that align well with the experiments. Using deep learning, we also fit the contribution of the quark spin to the nucleon spin $\Delta \Sigma$ and ultimately obtain $\Delta \Sigma \approx 0.23^{+0.02}_{-0.06}$, consistent with global fit results $\Delta \Sigma = 0.24\pm0.07$. |
