Impact of JLab data on the determination of GPDs at zero skewness and new insights from transition form factors N→Δ

Abstract

It is well-established now that the generalized parton distributions (GPDs) at zero skewness are playing important roles in some physical process such as elastic electron-nucleon scattering, elastic (anti)neutrino-nucleon scattering, and wide-angle Compton scattering (WACS) via various types of form factors (FFs). In this study, we are going to utilize the recent JLab measurements of the elastic electron-nucleon scattering reduced cross section, namely GMp12, as a touchstone to unravel the tension observed between the measurements of the WACS cross section and the data of the proton magnetic FF GMp. We also investigate the impact of GMp12 data on valence unpolarized GPDs Hvq and Evq at zero skewness by performing some χ2 analyses of the related experimental data. By calculating the electric and scalar quadrupole ratios, REM and RSM, and magnetic transition FF GM*/3GD related to the nucleon-to-delta (N→Δ) transition using the extracted GPDs and comparing the results with corresponding experimental measurements, we show that our results are in an excellent consistency with experiments, indicating the universality property of GPDs. We emphasize that the inclusion of these data in the future analysis of GPDs can significantly affect the extracted GPDs especially their uncertainties at smaller values of Q2. Published by the American Physical Society 2024