Excited-state contamination in nucleon correlators from chiral perturbation theory

Understand

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.