Axial nucleon form factors from lattice QCD

We present results on the nucleon axial form factors within lattice QCD using two flavors of degenerate twisted mass fermions. Volume effects are examined using simulations at two volumes of spatial length L=2.1fm and L=2.8fm. Cut-off effects are investigated using three different values of the lattice spacings, namely a=0.089fm, a=0.070fm and a=0.056fm. The nucleon axial charge is obtained in the continuum limit and chirally extrapolated to the physical pion mass enabling comparison with experiment. © 2011 American Physical Society.