Double Deeply Virtual Compton Scattering as a probe of Generalized Parton Distributions

Abstract: Generalized Parton Distributions (GPDs) are multidimensional structure functions of hadrons, encoding mechanical and spin properties through the correlation of the momentum and transverse position of partons. While channels like Deeply Virtual Compton Scattering (DVCS) access GPDs in a constrained kinematic domain, Double Deeply Virtual Compton Scattering (DDVCS) offers broader access to the GPD phase space, though it remains unmeasured. We present a feasibility study of DDVCS observables using polarized electron beams at Jefferson Lab and the EIC, focusing on their sensitivity to helicity-conserving GPDs and implications for Compton Form Factor (CFF) extraction. Moreover, we provide experimental projections supporting the feasibility of the measurements at both facilities.