Positive-parity Excited-states of the Nucleon in Quenched Lattice QCD

Abstract

Positive-parity spin-1/2 excitations of the nucleon are explored in lattice QCD. The variational method is used in this investigation and several correlation matrices are employed. As our focus is on the utility and methodology of the variational approach, we work in the quenched approximation to QCD. Various sweeps of Gaussian fermion-field smearing is applied at the source and at the sink of ${\chi }_1{\bar{\chi }}_1$ and ${\chi }_1{\chi }_2$ correlation functions to obtain a large basis of operators. Using several different approaches for constructing basis interpolators, we demonstrate how improving the basis can split what otherwise might be interpreted as a single state into multiple eigenstates. Consistency of the extracted excited energy states are explored over various dimensions of the correlation matrices. The use of large correlation matrices is emphasized for the reliable extraction of the excited eigenstates of QCD.

14 pages. 12 figures, added some references and 1 figure, some sections have been revised, results unchanged

References in corpus (6)

• Ab-initio Determination of Light Hadron Masses
• Excited hadrons on the lattice: Baryons
• Lattice QCD determination of patterns of excited baryon states
• Excited State Nucleon Spectrum with Two Flavors of Dynamical Fermions
• Ordering of Spin-$\frac{1}{2}$ Excitations of the Nucleon in Lattice QCD
• Isolating the Roper Resonance in Lattice QCD

Cited by in corpus (7)

• Three particle quantization condition in a finite volume: 2. general formalism and the analysis of data
• Light Hadron Masses from Lattice QCD
• Three-particle quantization condition in a finite volume: 1. The role of the three-particle force
• A novel analysis method for excited states in lattice QCD - the nucleon case
• Lattice baryon spectroscopy with multi-particle interpolators
• Ordering of Spin-$\frac{1}{2}$ Excitations of the Nucleon in Lattice QCD
• Excited States of the Nucleon in 2+1 Flavor QCD