$N\pi$-states and the projection method for the nucleon axial and pseudoscalar form factors

Abstract

The RQCD collaboration proposed a projection method to remove the excited state contamination in lattice OCD calculations of nuclear form factors. The effectiveness of this method in removing the two-particle nucleon-pion-state contamination is examined using chiral perturbation theory. It is shown that the projection method has practically no impact in the calculation of the axial and induced pseudoscalar form factors. In the pseudoscalar form factor the projection method strongly enhances the nucleon-pion-state contamination. The generalized Goldberger-Treiman relation is satisfied even though large nucleon-pion-state contaminations are present in individual form factors. Therefore, the projection method is not a solution to the excited state problem in nucleon form factor calculations.

17 pages, 5 figures

References in corpus (5)

• Nucleon isovector couplings from $N_f=2$ lattice QCD
• $N\pi$-state contamination in lattice calculations of the nucleon axial form factors
• Nucleon form factors from quenched lattice QCD with domain wall fermions
• Chiral perturbation theory and nucleon-pion-state contaminations in lattice QCD
• Nucleon-pion-state contribution in lattice calculations of moments of parton distribution functions

Cited by in corpus (7)

• Nucleon axial-vector and pseudoscalar form factors, and PCAC relations
• Toward $N$ to $N\pi$ matrix elements from lattice QCD
• Excited states in nucleon structure calculations
• $N\pi$-state contamination in lattice calculations of the nucleon electromagnetic form factors
• Detailed analysis of excited state systematics in a lattice QCD calculation of $g_A$
• Investigation of pion-nucleon contributions to nucleon matrix elements
• Elastic Nucleon-Pion scattering amplitudes in the $\Delta$ channel at physical pion mass from Lattice QCD