Progress with excited states in lattice QCD

Morningstar, Colin; Bulava, John; Fahy, Brendan; Foley, J.; Jhang, You-Cyuan; Juge, Keisuke Jimmy; Lenkner, David; Wong, Chik Him

doi:10.1063/1.4826815

Cited by 18 publications

(32 citation statements)

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“…Research is already well underway in exploring the best manner to do this [8,12,23,24]. The aim is to create correlation matrices composed from three-and five-quark operators.…”

Section: Discussionmentioning

confidence: 99%

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Searching for low-lying multi-particle thresholds in lattice spectroscopy

Mahbub¹,

Kamleh²,

Leinweber³

et al. 2014

Annals of Physics

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We explore the Euclidean-time tails of odd-parity nucleon correlation functions in a search for the S -wave pionnucleon scattering-state threshold contribution. The analysis is performed using 2 + 1 flavor 32 3 × 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 twoexponential 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 Nπ 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.

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“…Research is already well underway in exploring the best manner to do this [8,12,23,24]. The aim is to create correlation matrices composed from three-and five-quark operators.…”

Section: Discussionmentioning

confidence: 99%

“…Correlation matrices composed of traditional three-quark operators have been very successful in revealing a dense spectrum of baryon excited states in lattice QCD [1][2][3][4][5][6][7][8][9][10][11][12]. However the lowest lying multi-particle scattering state thresholds are often absent in the observed spectra.…”

Section: Introductionmentioning

confidence: 99%

Searching for low-lying multi-particle thresholds in lattice spectroscopy

Mahbub¹,

Kamleh²,

Leinweber³

et al. 2014

Annals of Physics

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“…Further analysis of finite volume effects [51] on the spectrum is highly desirable. Future calculations should also investigate the use of five-quark operators to ensure better overlap with the multiparticle states and to better resolve and probe the excited state spectrum [35,42,43].…”

Section: Fig 6 (Color Onlinementioning

confidence: 99%

“…To monitor this we use the full covariance-matrix based 2 =dof in order to accurately assess the extent to which our effective mass function plateau is associated with a single state. Ultimately, in addition to the 3-quark operators, one needs to include 5-or 7-or more-quark operators [35,42,43] in the correlation matrix to extract all the states in the spectrum.…”

Section: Introductionmentioning

confidence: 99%

Structure and flow of the nucleon eigenstates in lattice QCD

et al. 2013

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A determination of the excited energy eigenstates of the nucleon, s = 1 2 , I = 1 2 , N ± , is presented in full QCD using 2 + 1 flavor PACS-CS gauge configurations. The correlation-matrix method is used and is built using standard nucleon interpolators employing smearings at the fermion sources and sinks. We develop and demonstrate a new technique that allows the eigenvectors obtained to be utilized to track the propagation of the intrinsic nature of energy-states from one quark mass to the next. This approach is particularly useful for larger dimension correlation matrices where more near-degenerate energy-states can appear in the spectrum.

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“…In a series of papers [1,2,3,4,5,6], we have been striving to compute the finite-volume stationary-state energies of QCD using Markov-chain Monte Carlo integration of the QCD path integrals formulated on a space-time lattice. In this talk, our progress made during the past year is described.…”

Section: Introductionmentioning

confidence: 99%

Excited isovector mesons using the stochastic LapH method

Morningstar¹,

Fahy²,

Jhang³

et al. 2015

Proceedings of the 32nd International Symposium on Lattice Field Theory — PoS(LATTICE2014)

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The spectrum of excited isovector mesons is studied using a 32 3 × 256 anisotropic lattice with u, d quark masses set to give a pion mass near 240 MeV. Results in the bosonic isovector nonstrange symmetry channels of zero total momentum are presented using correlation matrices of unprecedented size. In addition to spatially-extended single-meson operators, large numbers of two-meson operators are used, involving a wide variety of light isovector, isoscalar, and strange meson operators of varying relative momenta. All needed Wick contractions are efficiently evaluated using a stochastic method of treating the low-lying modes of quark propagation that exploits Laplacian Heaviside quark-field smearing. Level identification is discussed.

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Progress with excited states in lattice QCD

Cited by 18 publications

References 0 publications

Searching for low-lying multi-particle thresholds in lattice spectroscopy

Searching for low-lying multi-particle thresholds in lattice spectroscopy

Structure and flow of the nucleon eigenstates in lattice QCD

Excited isovector mesons using the stochastic LapH method

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