Deeply-virtual Compton process e^- N → e^- γπN to study nucleon to resonance transitions

2023/02/28 by Semenov-Tian-Shansky, Kirill M., Vanderhaeghen, Marc
#FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Nuclear Theory (nucl-th)

paper · doi:10.48550/arxiv.2303.00119

Abstract

We study the deeply-virtual Compton scattering (DVCS) process e^- N → e^- γπN involving the transition between a nucleon and a nucleon resonance in the πN system, within the framework of generalized parton distributions (GPDs). For the four lowest-lying nucleon resonances, Δ(1232), P₁₁(1440), D₁₃(1520), and S₁₁(1535), we express the DVCS amplitude in the Bjorken limit in terms of corresponding nucleon-to-resonance GPDs. Building upon the knowledge of the well studied electromagnetic nucleon-to-resonance transition form factors, which map the quark charge densities in transverse position space, the corresponding GPDs will open the prospect to also access the longitudinal momentum distributions of quarks in the transition. We provide estimates for cross sections and beam-spin asymmetries in the first and second πN resonance regions in the kinematics of forthcoming CLAS12 data from Jefferson Lab.

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