Scattering in the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>π</mml:mi><mml:mi>N</mml:mi></mml:math>negative parity channel in lattice QCD

Lang, C. B.; Verduci, V.

doi:10.1103/physrevd.87.054502

Cited by 124 publications

(164 citation statements)

References 84 publications

(172 reference statements)

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“…Consequently, also here the errors are substantial and the results by far do not have the quality of the positive-parity ground state calculations. Nevertheless, within error bars there is agreement between different groups that the N (1535) is seen although the extracted mass is still larger than the experimental one, see [264,279,416,417,425,427] and references therein. The structure of this state has been investigated in Ref.…”

Section: Octet and Decuplet Baryonsmentioning

confidence: 84%

“…For example, the first radial excitation of the nucleon, the Roper, will be affected by the presence of (p-wave) πN scattering states and therefore meson-nucleon interpolators should be included in the operator basis [281]. Whether these have a material impact is not clear from an outsider's perspective since potentially conflicting results have been found by different lattice groups [279,280]. We will return to the issue in the results part of this section.…”

Section: Extracting the Hadron Spectrum From Qcdmentioning

confidence: 96%

“…Another reason are the large operator bases involved in such extractions and the need for taking into account multiquark operators with the same quark content as the scattering states to provide maximal overlap. For baryons such bases have only been begun to be studied [279,280]. The influence of scattering states, however, may be important already in the positive-and negative-parity nucleon channel.…”

Section: Extracting the Hadron Spectrum From Qcdmentioning

confidence: 99%

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Baryons as relativistic three-quark bound states

Eichmann

Sanchis-Alepuz

Williams

et al. 2016

Progress in Particle and Nuclear Physics

436

530

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We review the spectrum and electromagnetic properties of baryons described as relativistic three-quark bound states within QCD. The composite nature of baryons results in a rich excitation spectrum, whilst leading to highly non-trivial structural properties explored by the coupling to external (electromagnetic and other) currents. Both present many unsolved problems despite decades of experimental and theoretical research. We discuss the progress in these fields from a theoretical perspective, focusing on nonperturbative QCD as encoded in the functional approach via Dyson-Schwinger and Bethe-Salpeter equations. We give a systematic overview as to how results are obtained in this framework and explain technical connections to lattice QCD. We also discuss the mutual relations to the quark model, which still serves as a reference to distinguish 'expected' from 'unexpected' physics. We confront recent results on the spectrum of non-strange and strange baryons, their form factors and the issues of two-photon processes and Compton scattering determined in the DysonSchwinger framework with those of lattice QCD and the available experimental data. The general aim is to identify the underlying physical mechanisms behind the plethora of observable phenomena in terms of the underlying quark and gluon degrees of freedom.

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Section: Octet and Decuplet Baryonsmentioning

confidence: 84%

Section: Extracting the Hadron Spectrum From Qcdmentioning

confidence: 96%

Section: Extracting the Hadron Spectrum From Qcdmentioning

confidence: 99%

See 1 more Smart Citation

Baryons as relativistic three-quark bound states

Eichmann

Sanchis-Alepuz

Williams

et al. 2016

Progress in Particle and Nuclear Physics

436

530

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show abstract

“…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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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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“…The pink hatched area, in contrast to the cyan one, also takes into account that the centroids of the generated pseudo-data scatter according to the assumed uncertainty (size of the error bars). Recently, first results on the spectrum of excited baryons including the decay dynamics have appeared [26]. A few phase shift points could be extracted using Lüscher's method, and first evidence for the N (1535)1/2 − and the N (1650)1/2 − resonances could be found.…”

Section: Multi-channel Scatteringmentioning

confidence: 99%

Resonance Extraction from the Finite Volume

Döring¹,

Molina²

2016

Proceedings of the 10th International Workshop on the Physics of Excited Nucleons (NSTAR2015)

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The spectrum of excited hadrons becomes accessible in simulations of Quantum Chromodynamics on the lattice. Extensions of Lüscher's method allow to address multi-channel scattering problems using moving frames or modified boundary conditions to obtain more eigenvalues in finite volume. As these are at different energies, interpolations are needed to relate different eigenvalues and to help determine the amplitude. Expanding the T -or the K-matrix locally provides a controlled scheme by removing the known non-analyticities of thresholds. This can be stabilized by using Chiral Perturbation Theory. Different examples to determine resonance pole parameters and to disentangle resonances from thresholds are discussed, like the scalar meson f 0 (980) and the excited baryons N (1535)1/2 − and Λ(1405)1/2 − .

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Scattering in theπNnegative parity channel in lattice QCD

Cited by 124 publications

References 84 publications

Baryons as relativistic three-quark bound states

Baryons as relativistic three-quark bound states

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

Resonance Extraction from the Finite Volume

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