1. Generalized parton distributions from the off-forward Compton amplitude in lattice QCD.
- Author
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Hannaford-Gunn, A., Can, K. U., Horsley, R., Nakamura, Y., Perlt, H., Rakow, P. E. L., Schierholz, G., Stüben, H., Young, R. D., and Zanotti, J. M.
- Subjects
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OPERATOR product expansions , *PARTONS , *QUANTUM chromodynamics , *MOMENTUM transfer - 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. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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