Document Type

Article

Publication Date

2021

DOI

10.1103/PhysRevD.103.114512

Publication Title

Physical Review D

Volume

103

Issue

11

Pages

114512 (1-32)

Abstract

This work explores scattering amplitudes that couple two-particle systems via a single external current insertion, 2 + J → 2. Such amplitudes can provide structural information about the excited QCD spectrum. We derive an exact analytic representation for these reactions. From these amplitudes, we show how to rigorously define resonance and bound-state form factors. Furthermore, we explore the consequences of the narrow-width limit of the amplitudes as well as the role of the Ward-Takahashi identity for conserved vector currents. These results hold for any number of two-body channels with no intrinsic spin, and a current with arbitrary Lorentz structure and quantum numbers. This work and the existing finite-volume formalism provide a complete framework for determining this class of amplitudes from lattice QCD.

Comments

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license (CC BY 4.0). 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.

Original Publication Citation

Briceño, R. A., Jackura, A. W., Ortega-Gama, F. G., & Sherman, K. H. (2021). On-shell representations of two-body transition amplitudes: Single external current. Physical Review D, 103(11), 1-32, Article 114512. https://doi.org/10.1103/PhysRevD.103.114512

ORCID

0000-0003-1109-1473 (Briceño), 0000-0002-3249-5410 (Jackura)

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