The Roper Puzzle

Keh Fei Liu, Ying Chen, Ming Gong, Raza Sufian, Mingyang Sun, Anyi Li

Research output: Contribution to journalConference articlepeer-review

1 Scopus citations


We carried out a calculation of the Roper state with the Sequential Empirical Bayesian (SEB) method with overlap valence fermion on 2+1-flavor domain-wall fermion configurations on the 243×64 lattice with a-1 = 1:73 GeV. The light sea quark mass corresponds to a pion mass of 330 MeV. The mass of the Roper, chirally extrapolated to the physical pion mass, is 1404(112) MeV which is consistent with the experimental value at 1440 MeV. When compared to the Roper state calculation with variational method for Clover and twisted mass fermions, it is found that the Roper states from SEB with overlap fermion are systematically lower by 400 - 800 MeV for all the quark masses ranging from light to the strange mass region. We study the origin of the difference by exploring the size of the interpolation field in relation to the radial wavefunction of the Roper and also the dynamical influence of the higher Fock space.

Original languageEnglish
Article number507
JournalProceedings of Science
StatePublished - 2013
Event31st International Symposium on Lattice Field Theory, LATTICE 2013 - Mainz, Germany
Duration: Jul 29 2013Aug 3 2013

ASJC Scopus subject areas

  • General


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