The positive-parity nucleon spectrum is studied in 2 + 1 flavour lattice QCD in an attempt to discover novel low-lying energy eigenstates in the region of the Roper resonance. In this work, we employ standard three-quark interpolating fields and introduce new local five-quark meson-baryon operators that hold the possibility of revealing new states that have been missed in previous studies. Motivated by phenomenological arguments, five-quark interpolators based on the σN, πN and a0N channels are constructed. Despite the introduction of qualitatively different operators, no novel energy levels are extracted near the regime of the Roper resonance.
@article{arxiv.1704.08816,
title = {Spectroscopy with Local Multi-hadron Interpolators in Lattice QCD},
author = {Adrian L. Kiratidis and Waseem Kamleh and Derek B. Leinweber and Zhan-Wei Liu and Finn M. Stokes and Anthony W. Thomas},
journal= {arXiv preprint arXiv:1704.08816},
year = {2017}
}