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Toward an advanced phenomenology of πN transition distribution amplitudes

B. Pire1, K. Semenov-Tian-Shansky2,3, P. Sznajder4, and L. Szymanowski4

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Phys. Rev. D 112, 014023 – Published 9 July, 2025

DOI: https://doi.org/10.1103/6gc4-vnk9

Abstract

We introduce a new approach to modeling transition distribution amplitudes (TDAs) for the processes ep→enπ+ and ep→epπ0. The modeling is flexible, constrained by sparsely available experimental data, and satisfies theoretical requirements, including reduction to nucleon distribution amplitudes in the appropriate limit. We study the sensitivity of observable predictions to various modeling assumptions. We discuss unpolarized cross sections, as well as the three nonvanishing polarization observables at leading twist, namely, the single transverse target spin asymmetry and the two double spin asymmetries that occur with a polarized lepton beam on either a longitudinally or transversely polarized target. The analysis is complemented by a simple Monte Carlo study to provide guidance for exploring exclusive processes in the so-called backward kinematics. Our work aims to highlight the importance of future measurements to better constrain TDAs and to support upcoming experimental proposals.

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Phys. Rev. D 112, 014023– Published 9 July, 2025
  • Received 10 June 2025
  • Accepted 20 June 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

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