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arXiv · 1405.4077

Computation of the electromagnetic pion form factor from lattice QCD in the epsilon regime

H. Fukaya·S. Aoki·S. Hashimoto·T. Kaneko·H. Matsufuru·J. Noaki
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Abstract

We calculate the electromagnetic pion form factor in lattice QCD with 2+1 flavors of the dynamical overlap quarks. Up and down quark masses are set below their physical values so that the system is in the so-called epsilon regime with the small size of our lattice ~ 1.8 fm. The finite volume corrections are generally expected to be ~ 100% in the epsilon regime. We, however, find a way to automatically cancel the dominant part of them. Inserting non-zero momenta and taking appropriate ratios of the two and three point functions, we can eliminate the contribution from the zero-momentum pion mode. Then the remaining finite volume effect is a small perturbation from the non-zero modes. Our lattice data agree with this theoretical prediction and the extracted pion charge radius is consistent with the experiment.

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H. Fukaya, S. Aoki, S. Hashimoto, T. Kaneko, H. Matsufuru, J. Noaki. 2014-09-01. Computation of the electromagnetic pion form factor from lattice QCD in the epsilon regime. https://doi.org/10.1103/physrevd.90.034506

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