2013/10/31 by M. Selim Mahbub, Waseem Kamleh, Derek B. Leinweber +1
Chemistry · Physics and Astronomy · #Advanced NMR Techniques and Applications #Eigenvalues and eigenvectors #Exponential decay #Exponential function #Fermion #Mathematical analysis #Particle physics theoretical and experimental studies #Physics #Propagator #Quantum Chromodynamics and Particle Interactions #Quantum electrodynamics #Quantum mechanics #Quark #Scattering #Wave function #hep-lat
paper · pdf · doi:10.1016/j.aop.2014.01.004
8 pages, 4 figures. Manuscript accepted for publication
arxiv created 2014/01/10 · openalex publication_date 2014/01/15 · arxiv updated 2015/06/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We explore the Euclidean-time tails of odd-parity nucleon correlation functions in a search for the S-wave pion-nucleon scattering-state threshold contribution. The analysis is performed using 2+1 flavor 323 x 64 PACS-CS gauge configurations available via the ILDG. Correlation matrices composed with various levels of fermion source/sink smearing are used to project low-lying states. The consideration of 25,600 fermion propagators reveals the presence of more than one state in what would normally be regarded as an eigenstate-projected correlation function. This observation is in accord with the scenario where the eigenstates contain a strong mixing of single and multi-particle states but only the single particle component has a strong coupling to the interpolating field. Employing a two-exponential fit to the eigenvector-projected correlation function, we are able to confirm the presence of two eigenstates. The lower-lying eigenstate is consistent with a N-pi scattering threshold and has a relatively small coupling to the three-quark interpolating field. We discuss the impact of this small scattering-state contamination in the eigenvector projected correlation function on previous results presented in the literature.