Generalised Parton Distributions from Lattice Feynman-Hellmann Techniques

Abstract

We report on the use of Feynman-Hellmann techniques to calculate the off-forward Compton amplitude (OFCA) in lattice QCD. At leading-twist, the Euclidean OFCA is parameterised by the Mellin moments of generalised parton distributions (GPDs). Hence we extract GPD moments for two values of the soft momentum transfer, $t=-1.10,-2.20{\text{GeV}}^2$ and zero-skewness kinematics at an unphysical pion mass of $m_{\pi }\approx 470\text{MeV}$. This includes the first determination of the $n=4$ moments.

9 pages, 3 figures