Abstract
In this work we develop a Lorentz-covariant version of the previously derived formalism for relating finite-volume matrix elements to 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 couples to one of the two hadrons. This also leads to a new finite-volume function, denoted , the numerical evaluation of which is described in detail. As an example we discuss the determination of the amplitude in the channel, for which the single-pion form factor, , as well as the scattering phase, , are required to remove all power-law finite-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.
4 More- Received 12 March 2019
DOI:https://doi.org/10.1103/PhysRevD.100.034511
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.
Published by the American Physical Society