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arXiv · 1311.7686

Two-Baryon Systems with Twisted Boundary Conditions

Raul A. Briceno·Zohreh Davoudi·Thomas C. Luu·Martin J. Savage
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Abstract

We explore the use of twisted boundary conditions in extracting the nucleon mass and the binding energy of two-baryon systems, such as the deuteron, from Lattice QCD calculations. Averaging the results of calculations performed with periodic and anti-periodic boundary conditions imposed upon the light-quark fields, or other pair-wise averages, improves the volume dependence of the deuteron binding energy from ~exp(-kappa*L)/L to ~exp(-sqrt(2)kappa*L)/L. However, a twist angle of pi/2 in each of the spatial directions improves the volume dependence from ~exp(-kappa*L)/L to ~exp(-2kappa*L)/L. Twist averaging the binding energy with a random sampling of twist angles improves the volume dependence from ~exp^(-kappa*L)/L to ~exp(-2kappa*L)/L, but with a standard deviation of ~exp(-kappa*L)/L, introducing a signal-to-noise issue in modest lattice volumes. Using the experimentally determined phase shifts and mixing angles, we determine the expected energies of the deuteron states over a range of cubic lattice volumes for a selection of twisted boundary conditions.

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Raul A. Briceno, Zohreh Davoudi, Thomas C. Luu, Martin J. Savage. 2013-11-29. Two-Baryon Systems with Twisted Boundary Conditions. https://doi.org/10.1103/physrevd.89.074509

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