A new method for suppressing excited-state contaminations on the nucleon form factors

Abstract

One of the most challenging tasks in lattice calculations of baryon form factors is the analysis and control of excited-state contaminations. Taking the isovector axial form factors of the nucleon as an example, both a dispersive representation and a calculation in chiral effective field theory show that the excited-state contributions become dominant at fixed source-sink separation when the axial current is spatially distant from the nucleon source location. We address this effect with a new method in which the axial current is localized by a Gaussian wave-packet and apply it on a CLS ensemble with $N_f=2+1$ flavors of O($a$) improved Wilson fermions with a pion mass of $m_{\pi }=200$MeV.

arXiv comment7 pages, 6 figures, 1 table, Proceedings for the 36th Annual International Symposium on Lattice Field Theory, 22-28 July 2018, Michigan State University, East Lansing, Michigan, USA

References in corpus (8)

• Axial structure of the nucleon
• Simulation of QCD with N_f=2+1 flavors of non-perturbatively improved Wilson fermions
• Effective noise reduction techniques for disconnected loops in Lattice QCD
• Lattice QCD without topology barriers
• A new class of variance reduction techniques using lattice symmetries
• Setting the scale for the CLS $2+1$ flavor ensembles
• Variance Reduction and Cluster Decomposition
• Nucleon-pion-state contamination in lattice calculations of the axial form factors of the nucleon

Cited by in corpus (3)

• Nucleon axial structure from lattice QCD
• $N\pi$-state contamination in lattice calculations of the nucleon axial form factors
• Method for high-precision determination of the nucleon axial structure using lattice QCD: Removing $\pi N$-state contamination