Generalized parton distributions from the off-forward Compton amplitude in lattice QCD

Hannaford-Gunn, A, Can, KU, Horsley, R, Nakamura, Y, Perlt, H, Rakow, PEL ORCID: 0000-0003-4486-2158, Schierholz, G, Stueben, H, Young, RD and Zanotti, JM (2022) Generalized parton distributions from the off-forward Compton amplitude in lattice QCD. PHYSICAL REVIEW D, 105 (1). 014502-.

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Official URL: http://dx.doi.org/10.1103/physrevd.105.014502

Abstract

We determine the properties of generalized parton distributions (GPDs) from a lattice QCD calculation of the off-forward Compton amplitude (OFCA). By extending the Feynman-Hellmann relation to second-order matrix elements at off-forward kinematics, this amplitude can be calculated from lattice propagators computed in the presence of a background field. Using an operator product expansion, we show that the deeply virtual part of the OFCA can be parametrized in terms of the low-order Mellin moments of the GPDs. We apply this formalism to a numerical investigation for zero-skewness kinematics at two values of the soft momentum transfer, t=-1.1,-2.2 GeV2, and a pion mass of mπ≈470 MeV. The form factors of the lowest two moments of the nucleon GPDs are determined, including the first lattice QCD determination of the n=4 moments. Hence we demonstrate the viability of this method to calculate the OFCA from first principles, and thereby provide novel constraint on the x- and t-dependence of GPDs.

Item Type:	Article
Divisions:	Faculty of Science and Engineering > School of Physical Sciences
Depositing User:	Symplectic Admin
Date Deposited:	12 May 2022 11:42
Last Modified:	15 Mar 2024 07:27
DOI:	10.1103/PhysRevD.105.014502
Open Access URL:	https://journals.aps.org/prd/abstract/10.1103/Phys...
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3154659