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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.
Original language | English |
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Article number | 014502 |
Pages (from-to) | 1-19 |
Number of pages | 19 |
Journal | Physical Review D |
DOIs | |
Publication status | Accepted/In press - 20 Dec 2021 |
Keywords
- hep-lat
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Dive into the research topics of 'Generalised parton distributions from the off-forward Compton amplitude in lattice QCD'. Together they form a unique fingerprint.Projects
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Particle Theory at the Higgs Centre
Ball, R., Boyle, P., Del Debbio, L., Gardi, E., Horsley, R., Kennedy, A., O'Connell, D., Smillie, J. & Zwicky, R.
1/10/17 → 30/09/21
Project: Research