Excited States of the Nucleon in 2+1 Flavor QCD

Abstract

Recent developments on the determination of the spin-1/2 spectrum of the nucleon in full QCD are presented. Our focus is on the PACS-CS 2+1 flavor configurations made available through the ILDG. Using correlation matrix techniques, in which a wide variety of gauge-invariant Gaussian-smeared fermion-propagator sources and sinks are considered, excited states are determined. We consider several correlation matrices of various sizes, each constructed with a different set of basis interpolators, in order to demonstrate the invariance of the eigenstates on the basis choice. Of particular interest is the approach to the elusive Roper resonance and we report preliminary results in full QCD.

arXiv comment7 pages, 3 figures. Presented at the XXVIII International Symposium on Lattice Field Theory, Lattice2010, June 14-19, 2010, Villasimius, Italy

References in corpus (10)

• A New Way to Set the Energy Scale in Lattice Gauge Theories and its Application to the Static Force and ${\alpha }_s$ in SU(2) Yang--Mills Theory
• 2+1 Flavor Lattice QCD toward the Physical Point
• Excited Baryons in Lattice QCD
• Nucleon, $\Delta$ and $\Omega$ excited states in $N_f=2+1$ lattice QCD
• Excited State Nucleon Spectrum with Two Flavors of Dynamical Fermions
• Nucleon Properties from Unconventional Interpolating Fields
• Nonperturbative $O(a)$ improvement of the Wilson quark action with the RG-improved gauge action using the Schrödinger functional method
• Isolating Excited States of the Nucleon in Lattice QCD
• Positive-parity Excited-states of the Nucleon in Quenched Lattice QCD
• Isolating the Roper Resonance in Lattice QCD