Multi-hadron-state contamination in nucleon observables from chiral perturbation theory

Abstract

Multi-particle states with additional pions are expected to be a non-negligible source of the excited-state contamination in lattice simulations at the physical point. It is shown that baryon chiral perturbation theory (ChPT) can be employed to calculate the contamination due to two-particle nucleon-pion states in various nucleon observables. Results to leading order are presented for the nucleon axial, tensor and scalar charge and three Mellin moments of parton distribution functions: the average quark momentum fraction, the helicity and the transversity moment. Taking into account experimental and phenomenological results for the charges and moments the impact of the nucleon-pion-states on lattice estimates for these observables can be estimated. The nucleon-pion-state contribution leads to an overestimation of all charges and moments obtained with the plateau method. The overestimation is at the 5-10% level for source-sink separations of about 2 fm. Existing lattice data is not in conflict with the ChPT predictions, but the comparison suggests that significantly larger source-sink separations are needed to compute the charges and moments with few-percent precision.

17 pages, 8 figures. Talk given at the 35th International Symposium on Lattice Field Theory, 18 - 24 June 2017, Granada, Spain

References in corpus (9)

• Chiral Perturbation Theory and Baryon Properties
• Chiral Perturbation Theory and the first moments of the Generalized Parton Distriputions in a Nucleon
• Chiral perturbation theory and nucleon-pion-state contaminations in lattice QCD
• On the effect of excited states in lattice calculations of the nucleon axial charge
• Multi-boson block factorization of fermions
• An introduction to chiral perturbation theory
• Novel applications of Lattice QCD: Parton distribution functions, proton charge radius and neutron electric dipole moment
• Life Outside the Golden Window: Statistical Angles on the Signal-to-Noise Problem
• Taming the Signal-to-Noise Problem in Lattice QCD by Phase Reweighting

Cited by in corpus (13)

• FLAG Review 2019
• FLAG Review 2021
• Nucleon axial structure from lattice QCD
• FLAG Review 2024
• $N\pi$-state contamination in lattice calculations of the nucleon axial form factors
• Solving the PCAC puzzle for nucleon axial and pseudoscalar form factors
• $N\pi$-state contamination in lattice calculations of the nucleon pseudoscalar form factor
• $N\pi$-states and the projection method for the nucleon axial and pseudoscalar form factors
• Multi-boson block factorization of fermions
• $N\pi$-state contamination in lattice calculations of the nucleon electromagnetic form factors
• Three-particle $N\pi \pi$ state contribution to the nucleon two-point function in lattice QCD
• Hints and challenges in heavy flavor physics
• Nucleon-pion-state contamination in lattice calculations of the axial form factors of the nucleon