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  • Open Access

Multipole structure of the N→Δ transition generalized parton distributions

June-Young Kim* and Hyun-Chul Kim†

  • Department of Physics and Institute of Quantum Science, Inha University, Incheon 22212, Republic of Korea

  • *Contact author: jun-young.kim@inha.ac.kr
  • †Contact author: hchkim@inha.ac.kr
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Phys. Rev. D 114, 074023 – Published 13 October, 2026

DOI: https://doi.org/10.1103/1hr6-pbk8

Abstract

We establish the multipole structure of the N→Δ transition at the level of the generalized parton distributions (GPDs). We decompose the four transition GPDs into one monopole, two dipole, and one quadrupole components in the transverse plane by a multipole expansion of the covariant transition matrix element in terms of the three-dimensional spin-transition tensors and the transverse momentum transfer. These multipole components are in one-to-one correspondence with the light-front helicity amplitudes. In the zero-skewness limit, the multipole GPDs define impact-parameter transition densities, which generalize the transverse transition charge densities to the x-dependent level. These transition densities arise from nondiagonal matrix elements between two distinct hadronic states and must therefore be distinguished from the diagonal densities of the nucleon and the Δ. The multipole transition densities visualize the monopole, dipole, and quadrupole structures of the partonic N→Δ transition in the transverse plane.

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Phys. Rev. D 114, 074023– Published 13 October, 2026
  • Received 14 July 2026
  • Accepted 24 September 2026
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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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