# 36th Annual International Symposium on Lattice Field Theory

Jul 22 – 28, 2018
Kellogg Hotel and Conference Center
EST timezone

## The Slope of Form Factors from Lattice QCD

Jul 23, 2018, 4:50 PM
20m
105 (Kellogg Hotel and Conference Center)

### 105

#### Kellogg Hotel and Conference Center

219 S Harrison Rd, East Lansing, MI 48824

### Speaker

Chia Cheng Chang (iTHEMS RIKEN)

### Description

We present an update on the direct position-space method for calculating slopes of from factors from lattice QCD.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 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.

### Primary authors

Chia Cheng Chang (iTHEMS RIKEN) Christopher Bouchard (Ohio State) Dr David Richards (Jefferson Laboratory) Prof. Kostas Orginos Orginos (William and Mary / Jlab)

 Slides