Exploring the Roper resonance in Lattice QCD

Waseem Kamleh, Derek Leinweber, Dale S Roberts
2014 Proceedings of 31st International Symposium on Lattice Field Theory LATTICE 2013 — PoS(LATTICE 2013)   unpublished
Using a correlation matrix analysis consisting of a variety of smearings, the CSSM Lattice collaboration has successfully isolated states associated with the Roper resonance and other "exotic" excited states such as the Λ(1405) on the lattice at near-physical pion masses. We explore the nature of the Roper by examining the eigenvectors that arise from the variational analysis, demonstrating that the Roper state is dominated by the χ 1 nucleon interpolator and only poorly couples to χ 2 . By
more » ... ining the probability distribution of the Roper on the lattice, we find a structure consistent with a constituent quark model. In particular, the Roper d-quark wave function contains a single node consistent with a 2S state. A detailed comparison with constituent quark model wave functions is carried out, validating the approach of accessing these states by constructing a variational basis composed of different levels of fermion source and sink smearing.
doi:10.22323/1.187.0245 fatcat:pp7btnidhzfv3o67jsv3uens6a