0000000000623279
AUTHOR
B. Knippschild
showing 2 related works from this author
Nucleon axial charge in lattice QCD with controlled errors
2012
We report on our calculation of the nucleon axial charge ${g}_{\mathrm{A}}$ in QCD with two flavors 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 ${g}_{\mathrm{A}}=1.223\ifmmode\pm\else\textpm\fi{}0.063(\mathrm{stat}{)}_{\ensuremath{-}0.060}^{+0.035}(\mathrm{syst})$, in good agreement with the experimental value.
Nucleon electromagnetic form factors in two-flavor QCD
2015
We present results for the nucleon electromagnetic form factors, including the momentum transfer dependence and derived quantities (charge radii and magnetic moment). The analysis is performed using O(a) improved Wilson fermions in Nf=2 QCD measured on the CLS ensembles. Particular focus is placed on a systematic evaluation of the influence of excited states in three-point correlation functions, which lead to a biased evaluation, if not accounted for correctly. We argue that the use of summed operator insertions and fit ans\"atze including excited states allow us to suppress and control this effect. We employ a novel method to perform joint chiral and continuum extrapolations, by fitting th…