https://doi.org/10.1140/epjc/s10052-020-8417-5
Regular Article - Theoretical Physics
On the axial-vector form factor of the nucleon and chiral symmetry
1
GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planck Str. 1, 64291, Darmstadt, Germany
2
Technische Universität Darmstadt, 64289, Darmstadt, Germany
3
Van Swinderen Institute for Particle Physics and Gravity, University of Groningen, 9747, Groningen, AG, The Netherlands
Received:
19
May
2020
Accepted:
26
August
2020
Published online:
12
September
2020
We consider the chiral Lagrangian with nucleon, isobar, and pion degrees of freedom. The baryon masses and the axial-vector form factor of the nucleon are derived at the one-loop level. We explore the impact of using on-shell baryon masses in the loop expressions. As compared to results from conventional chiral perturbation theory we find significant differences. An application to QCD lattice data is presented. We perform a global fit to the available lattice data sets for the baryon masses and the nucleon axial-vector form factor, and determine the low-energy constants relevant at 
LO for the baryon masses and at 
LO for the form factor. Partial finite-volume effects are considered. We point out that the use of on-shell masses in the loops results in non-analytic behavior of the baryon masses and the form factor as function of the pion mass, which becomes prominent for larger lattice volumes than presently used.
© The Author(s) 2020
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