The negative-parity ground state of the \Lambda{} baryon lies surprisingly low in mass. At 1405.1 MeV, it lies lower than the negative-parity ground state nucleon, even though it has a valence strange quark. Using the PACS-CS (2+1)-flavour full-QCD ensembles available through the ILDG, we employ a variational analysis using source and sink smearing to isolate this elusive state. We find three low-lying odd-parity states, and for the first time reproduce the correct level ordering with respect to the nearby scattering thresholds.
@article{arxiv.1109.6716,
title = {Isolating the \Lambda(1405) in Lattice QCD},
author = {Benjamin J. Menadue and Waseem Kamleh and Derek B. Leinweber and M. Selim Mahbub},
journal= {arXiv preprint arXiv:1109.6716},
year = {2012}
}