18-22 October 2021
Matsue, Shimane Prefecture, Japan
Asia/Tokyo timezone

Spin effects in low-energy electron-nucleon scattering with two-photon exchange: Analysis based on 1/N_c expansion of QCD

21 Oct 2021, 07:50
Room 401 (Kunibiki Messe)

Room 401

Kunibiki Messe

Parallel Session Presentation Low energy spin physics with lepton, photon and hadron probes Low energy spin physics with lepton, photon and hadron probes


Cintia Willemyns (University of Mons)


The transverse single-spin asymmetry in inclusive electron-nucleon scattering, e + N(S_T) -> e’ + X, represents a pure two-photon exchange observable and is of fundamental interest for exploring higher-order QED effects in electron scattering. We compute this observable in the resonance region, where excitation of Delta isobars occurs in both intermediate and final states. We employ a novel theoretical method based on the large-N_c limit of QCD, which allows us to consistently combine nucleon and Delta states and predict the elastic, inelastic, and inclusive spin-dependent cross section. Our results aim at disentangling the different contributions of nucleon and Delta states organizing them according to their 1/N_c scaling. The case of the target single spin asymmetry will be discussed in detail. Our predictions could be tested in future measurements of electron-nucleon scattering with polarized targets in the few-GeV energy range. Such experiments would complement earlier measurements of the inclusive single-spin asymmetry in the DIS regime (JLab, HERMES) and allow one to study the unknown dependence of two-photon exchange dynamics on the energy/momentum of the probe.

Primary authors

Jose Goity (Hampton University, Jefferson Lab) Christian Weiss (Jefferson Lab) Cintia Willemyns (University of Mons)

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