Fitting strategies to extract the axial charge of the nucleon from lattice QCD

Jiayu Hua, Georg von Hippel, Benjamin Jaeger, Harvey Meyer, Thomas Rae, Hartmut Wittig
2014 Proceedings of 31st International Symposium on Lattice Field Theory LATTICE 2013 — PoS(LATTICE 2013)   unpublished
We report on a comparison of several fit methods used for the extraction of the nucleon axial charge g A from lattice QCD with two dynamical flavours of O(a) improved Wilson quarks. We use plateau fits, summed operator insertions (the summation method) and a new "midpoint" method to investigate contributions from excited states that affect the determination of g A . We also present a method to perform correlated fits when the standard estimator for the inverse of the covariance matrix becomes unstable.
doi:10.22323/1.187.0446 fatcat:a72lvfcvybfx7pecmpj7am4khq