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Hard exclusive $\pi^{+}n$ electro production beam spin asymmetries off the proton in the GPD and TDA regimes

S. Diehl for the CLAS collaboration

SciPost Phys. Proc. 8, 066 (2022) · published 12 July 2022

Proceedings event

28th Annual Workshop on Deep-Inelastic Scattering (DIS) and Related Subjects


Hard exclusive $\pi^{+}$n electro-production can be used to gain access to the 3D nucleon structure. The QCD factorisation mechanism in the "nearly forward region" ($t/Q^{2}$ small) allows a description by Generalized Parton Distributions (GPDs), while for the "nearly backward" kinematic region ($u/Q^{2}$ small) a description based on nucleon to pion transitions (TDAs) is available. The paper presents a measurement of single beam spin asymmetries to extract the $A^{\sin\phi}_{LU}$ moments and the related cross section ratio $\sigma_{LT^\prime}/\sigma_{0}$ from the hard exclusive $\pi^{+}$ channel off the unpolarized hydrogen target in a wide range of kinematics based on data taken with the CLAS spectrometer at Jefferson Lab. In addition, under forward angles a detailed multidimensional study will be presented based on CLAS12 data and compared to theoretical predictions.

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