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

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.

16pages, 5 figures, minor corrections, references added, published by PRD

References in corpus (7)

• Two-flavor lattice QCD simulation in the epsilon-regime with exact chiral symmetry
• Low energy chiral constants from epsilon-regime simulations with improved Wilson fermions
• The Chiral Condensate in a Finite Volume
• Lattice study of meson correlators in the epsilon-regime of two-flavor QCD
• Probing the chiral regime of Nf=2 QCD with mixed actions
• The condensate for two dynamical chirally improved quarks in QCD
• Electromagnetic form factor of pion from N_f=2+1 dynamical flavor QCD

Cited by in corpus (9)

• FLAG Review 2021
• Timelike pion form factor in lattice QCD
• The Present and Future of QCD
• Pion form factor and charge radius from Lattice QCD at physical point
• The valence quark, sea, and gluon content of the pion from the parton distribution functions and the electromagnetic form factor
• The scalar, vector and tensor form factors for the pion and kaon from lattice QCD
• QCD Predictions for Meson Electromagnetic Form Factors at High Momenta: Testing Factorization in Exclusive Processes
• Spin-orbit correlation and spatial distributions for spin-0 hadrons
• Extracting the electro-magnetic pion form factor from QCD in a finite volume