Document Type

Article

Publication Date

2019

DOI

10.1103/PhysRevD.100.034511

Publication Title

Physical Review D

Volume

100

Issue

3

Pages

034511 (1-38)

Abstract

In this work we develop a Lorentz-covariant version of the previously derived formalism for relating finite-volume matrix elements to 2 + J → 2 transition amplitudes. We also give various details relevant for the implementation of this formalism in a realistic numerical lattice QCD calculation. Particular focus is given to the role of single-particle form factors in disentangling finite-volume effects from the triangle diagram that arise when J couples to one of the two hadrons. This also leads to a new finite-volume function, denoted G, the numerical evaluation of which is described in detail. As an example we discuss the determination of the ππ+ J → ππ amplitude in the ρ channel, for which the single-pion form factor, Fπ(Q2), as well as the scattering phase, δππ, are required to remove all power-law (mite-volume effects. The formalism presented here holds for local currents with arbitrary Lorentz structure, and we give specific examples of insertions with up to two Lorentz indices.

Comments

Published under the terms of the Creative Commons Attribution 4.0 International license.

Original Publication Citation

Baroni, A., Briceno, R. A., Hansen, M. T., & Ortega-Gama, F. G. (2019). Form factors of two-hadron states from a covariant finite-volume formalism. Physical Review D, 100(3), 034511. doi:10.1103/PhysRevD.100.034511

ORCID

0000-0003-1109-1473 (Briceno)

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