June 29, 2015 to July 3, 2015
Europe/Rome timezone

Excited-state contamination in nucleon correlators from chiral perturbation theory

Jun 30, 2015, 4:50 PM
Room PS4 (Building E, Polo Fibonacci, Pisa)

Room PS4

Building E, Polo Fibonacci, Pisa

Talk Hadron Structure and Meson-Baryon Interaction Working Group Parallel Session 4 - Hadron Structure & Meson-Baryon Interaction WG


Brian Tiburzi (City College of New York)


Techniques to compute hadron properties from lattice QCD rely upon the limit of long time separation. For baryons, the signal-to-noise problem often restricts one to time separations that are not ideally long, and for which couplings to excited states can obstruct the isolation of ground-state baryon properties. We consider excited-state contamination in nucleon two- and three-point functions. Using chiral perturbation theory, we determine couplings to pion-nucleon and pion-delta excited states. In two-point functions, these contributions are small, in accordance with general properties of the spectral density on a torus. For the axial-current correlation function in the nucleon, the sign of excited-state contributions suggests overestimation of the nucleon axial charge. Thus contamination from pion-nucleon excited states will not likely explain the trend in lattice QCD data.

Primary author

Brian Tiburzi (City College of New York)

Presentation materials