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arXiv · 2509.05059

Dispersion relations of deeply virtual Compton scattering: investigating twist-4 kinematic power corrections

Abstract

In this paper we include kinematic power corrections up to twist-four to the deeply virtual Compton scattering dispersion relation. We demonstrate that, both for (pseudo-)scalar and spin-$1/2$ targets, the formal expression of the $n$-subtracted leading-twist dispersion relations is preserved. However, the expression of the subtracted constants is modified by the kinematic powers. Importantly, the minimal-subtracted dispersion relation for the helicity-conserving amplitude, previously thought to depend only on the Polyakov-Weiss $D$-term, now also depends on the double distributions $F$ and $K$. These results are consistent with the ones obtained previously in the literature. Such a mixing may be critical for the Jefferson Lab kinematic range, as it is not suppressed for typical values of $t$ and $Q^{2}$ in the valence region. We therefore expect a strong impact on attempts to extract pressure forces from DVCS data.

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Víctor Martínez-Fernández, Cédric Mezrag. 2026-03-04. Dispersion relations of deeply virtual Compton scattering: investigating twist-4 kinematic power corrections. https://arxiv.org/abs/2509.05059

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