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Nucleon axial charge in lattice QCD with controlled errors

2012; American Physical Society; Volume: 86; Issue: 7 Linguagem: Inglês

10.1103/physrevd.86.074502

1550-7998

Stefano Capitani, Michele Della Morte, Georg von Hippel, Benjamin Jäger, Andreas Jüttner, Bastian Knippschild, Harvey B. Meyer, Hartmut Wittig,

High-Energy Particle Collisions Research

We report on our calculation of the nucleon axial charge gA in QCD with two flavours of dynamical quarks. A detailed investigation of systematic errors is performed, with a particular focus on contributions from excited states to three-point correlation functions. The use of summed operator insertions allows for a much better control over such contamination. After performing a chiral extrapolation to the physical pion mass, we find gA=1.223 +/- 0.063 (stat) +0.035 -0.060 (syst), in good agreement with the experimental value.