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

Excited-state contamination in nucleon correlators from chiral perturbation theory

Jun 30, 2015, 4:50 PM
20m
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

Speaker

Brian Tiburzi (City College of New York)

Description

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