Volume 256 - 34th annual International Symposium on Lattice Field Theory (LATTICE2016) - Hadron Structure
Matrix elements from moments of correlation functions
C.C. Chang,* C. Bouchard, K. Orginos, D.G. Richards
*corresponding author
Full text: pdf
Pre-published on: 2016 December 27
Published on: 2017 March 24
Abstract
Momentum-space derivatives of matrix elements can be related to their coordinate-space moments through the Fourier transform. We derive these expressions as a function of momentum transfer $Q^2$ for asymptotic in/out states consisting of a single hadron. We calculate corrections to the finite volume moments by studying the spatial dependence of the lattice correlation functions. This method permits the computation of not only the values of matrix elements at momenta accessible on the lattice, but also the momentum-space derivatives, providing {\it a priori} information about the $Q^2$ dependence of form factors. As a specific application we use the method, at a single lattice spacing and with unphysically heavy quarks, to directly obtain the slope of the isovector form factor at various $Q^2$, whence the isovector charge radius. The method has potential application in the calculation of any hadronic matrix element with momentum transfer, including those relevant to hadronic weak decays.
DOI: https://doi.org/10.22323/1.256.0170
Open Access