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arXiv · 2303.12681

Target normal single-spin asymmetry in inclusive electron-nucleon scattering in the 1/Nc expansion

Jose L. Goity·Christian Weiss·Cintia Willemyns
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Abstract

The target normal single-spin asymmetry in inclusive electron-nucleon scattering is studied in the low-energy regime that includes the $\Delta$ resonance. The particular interest in the asymmetry resides in that it is driven by two-photon exchange effects. It probes the spin-dependent absorptive part of the two-photon exchange amplitude, which is free of infrared and collinear singularities and represents the most pristine expression of two-photon exchange dynamics. The study presented here uses the 1/Nc expansion of QCD, which combines the $N$ and $\Delta$ through the emergent SU(4) spin-flavor symmetry in the baryon sector and allows for a systematic construction of the transition EM currents. The analysis includes the first subleading corrections in the 1/Nc expansion and presents results for elastic and inelastic final states. The asymmetry is found to be in the range $10^{-3}-10^{-2}$. The $\Delta$ resonance plays an important role as an intermediate state in the elastic asymmetry and as a final state in the inclusive asymmetry.

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Jose L. Goity, Christian Weiss, Cintia Willemyns. 2023-03-22. Target normal single-spin asymmetry in inclusive electron-nucleon scattering in the 1/Nc expansion. https://doi.org/10.1103/physrevd.107.094026

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