$N\pi$-state contamination in lattice calculations of the nucleon axial form factors

Abstract

The nucleon-pion-state contribution to QCD two-point and three-point functions used in lattice calculations of the nucleon axial form factors are studied in chiral perturbation theory. For small quark masses this contribution is expected to be the dominant excited-state contamination at large time separations. To leading order in chiral perturbation theory the results depend on only two experimentally known low-energy constants and the nucleon-pion-state contribution to the form factors can be estimated. The nucleon-pion-state contribution to the axial form factor $G_{\mathrm{A}}(Q^2)$ is at the 5 percent level for a source-sink separation of 2 fm and shows almost no dependence on the momentum transfer $Q^2$. In contrast, for the induced pseudoscalar form factor ${\tilde{G}}_{\mathrm{P}}(Q^2)$ the nucleon-pion-state contribution shows a rather strong dependence on $Q^2$ and leads to a 10 to 40 percent underestimation of ${\tilde{G}}_{\mathrm{P}}(Q^2)$ at small momentum transfers. The ChPT results can be used to analytically remove the nucleon-pion-state contribution from lattice data. Performing this removal for lattice data generated by the PACS collaboration we find agreement with experimental data and the predictions of the pion-pole dominance model. The removal works surprisingly well even for source-sink separations as small as 1.3 fm.

arXiv comment30 pages, 11 figures

References in corpus (24)

• The nucleon axial charge from lattice QCD with controlled errors
• Axial Vector Form Factors of the Nucleon from Lattice QCD
• Nucleon axial form factors using lattice QCD simulations with a physical value of the pion mass
• Axial, induced pseudoscalar, and pion-nucleon form factors in manifestly Lorentz-invariant chiral perturbation theory
• Up, down, and strange nucleon axial form factors from lattice QCD
• Iso-vector axial form factors of the nucleon in two-flavour lattice QCD
• Nucleon form factors on a large volume lattice near the physical point in 2+1 flavor QCD
• Chiral perturbation theory for gradient flow observables
• Domain decomposition, multi-level integration and exponential noise reduction in lattice QCD
• A local factorization of the fermion determinant in lattice QCD
• Solving the PCAC puzzle for nucleon axial and pseudoscalar form factors
• Nucleon-pion-state contribution in lattice calculations of the nucleon charges $g_A,g_T$ and $g_S$
• Nucleon-pion-state contribution to nucleon two-point correlation functions
• Chiral Corrections to Nucleon Two- and Three-Point Correlation Functions
• Time Dependence of Nucleon Correlation Functions in Chiral Perturbation Theory
• Chiral perturbation theory and nucleon-pion-state contaminations in lattice QCD
• Chiral extrapolation of nucleon wave function normalization constants
• Excited-state contribution to the axial-vector and pseudo-scalar correlators with two extra pions
• Multi-hadron-state contamination in nucleon observables from chiral perturbation theory
• Nucleon-pion-state contribution in lattice calculations of moments of parton distribution functions
• Nucleon Axial and Electromagnetic Form Factors
• Three-particle $N\pi \pi$ state contribution to the nucleon two-point function in lattice QCD
• Nucleon-pion-state contamination in lattice calculations of the axial form factors of the nucleon
• A new method for suppressing excited-state contaminations on the nucleon form factors

Cited by in corpus (25)

• Proton and neutron electromagnetic form factors from lattice QCD
• Axial Vector Form Factors from Lattice QCD that Satisfy the PCAC Relation
• Nucleon axial, tensor and scalar charges and $\sigma$-terms in lattice QCD
• Precision Nucleon Charges and Form Factors Using 2+1-flavor Lattice QCD
• White Paper on New Opportunities at the Next-Generation Neutrino Experiments (Part 1: BSM Neutrino Physics and Dark Matter)
• Nucleon axial structure from lattice QCD
• Moments of nucleon generalized parton distributions from lattice QCD simulations at physical pion mass
• Event Generators for High-Energy Physics Experiments
• Nucleon axial and pseudoscalar form factors from lattice QCD at the physical point
• Isovector electromagnetic form factors of the nucleon from lattice QCD and the proton radius puzzle
• Status of Lattice QCD Determination of Nucleon Form Factors and their Relevance for the Few-GeV Neutrino Program
• The pion-nucleon sigma term from lattice QCD
• Nucleon axial-vector and pseudoscalar form factors, and PCAC relations
• $N\pi$-state contamination in lattice calculations of the nucleon pseudoscalar form factor
• Toward $N$ to $N\pi$ matrix elements from lattice QCD
• $N\pi$-states and the projection method for the nucleon axial and pseudoscalar form factors
• Excited states in nucleon structure calculations
• $N\pi$-state contamination in lattice calculations of the nucleon electromagnetic form factors
• Theoretical tools for neutrino scattering: interplay between lattice QCD, EFTs, nuclear physics, phenomenology, and neutrino event generators
• Investigation of pion-nucleon contributions to nucleon matrix elements
• Axial transition form factors of octet baryons in the perturbative chiral quark model
• Excited-state effects in nucleon structure on the lattice using hybrid interpolators
• Method for high-precision determination of the nucleon axial structure using lattice QCD: Removing $\pi N$-state contamination
• Application of Laplace filters to the analysis of lattice time correlators
• A Lattice Story of Proton Spin