An analysis of the nucleon spectrum from lattice partially-quenched QCD

Armour, Wes; Allton, Chris; Leinweber, Derek B.; Thomas, A. W.; Young, R.

doi:10.1016/j.nuclphysa.2010.03.012

Cited by 17 publications

(14 citation statements)

References 37 publications

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“…Only with the specific introduction of four-quark operators, could the ππ contributions to the channel be resolved. This is in accord with the very different nature of the quark flow diagrams and associated couplings describing meson dressings of mesons and baryons in QCD [21,22].…”

Section: Resultssupporting

confidence: 63%

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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Section: Resultssupporting

confidence: 63%

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

Mahbub¹,

Kamleh²,

Leinweber³

et al. 2014

Annals of Physics

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“…When vector mesons are included, the result is close to the experiments with Q 2 less than 0.4 GeV 2 [21].An alternative regularization method, namely finite-range-regularization (FRR) has been proposed. Inspired by quark models that account for the finite-size of the nucleon as the source of the pion cloud, effective field theory with FRR has been widely applied to extrapolate the vector meson mass, magnetic moments, magnetic form factors, strange form factors, charge radii, first moments of GPDs, nucleon spin, etc [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]. In the finite-range-regularization, there is no cut for the energy integral.…”

mentioning

confidence: 99%

Strange form factors of the nucleon with a nonlocal chiral effective Lagrangian

Wang

2018

Phys. Rev. D

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The strange form factors of the nucleon are studied with the nonlocal chiral effective Lagrangian. One loop contributions from both octet and decuplet intermediate states are included. The relativistic regulator is obtained by the nonlocal Lagrangian where the gauge link is introduced to guarantee the local gauge symmetry. With the kaon loop, the calculated charge form factor is positive, while the magnetic form factor is negative. The strange magnetic moment is −0.041 þ0.012 −0.014 with Λ ¼ 0.9 AE 0.1 determined from the nucleon electromagnetic form factors. Our results are comparable with the recent lattice simulation.

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“…f 1 (a) ≡ −0.888a 2 + 1.01a 2 log(a) − 1.55a 2 (log(a) + 1.20) −0.402a 2 (log(a) + 1.24) − 0.00369a + 0.280a log(a) + 0.310 (15) f 2 (a) ≡ (5.48a 2 + 1.46a 2 log(a) + 2.39a 2 (log(a) + 1.20) +0.128a 2 (log(a) + 1.24) + 1.02a + 0.318a log(a) − 0.0196), (16) where the tilde indicates that a chiral expansion has been made. The terms of order µ 4 log µ 2 emphasized by [5], [34] are included, but the expression also contains previously noted [33] dominating non-analytic terms of the form µ 2 log µ 2 . The total pionic contribution to the nucleon mass Σ π is given by…”

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confidence: 99%

Taming the Pion Cloud of the Nucleon

Alberg

Miller

2012

Phys. Rev. Lett.

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We present a light-front determination of the pionic contribution to the nucleon self-energy, Σ(π), to second order in pion-baryon coupling constants that allows the pion-nucleon vertex function to be treated in a model-independent manner constrained by experiment. The pion mass μ dependence of Σ(π) is consistent with chiral perturbation theory results for small values of μ and is also linearly dependent on μ for larger values, in accord with the results of lattice QCD calculations. The derivative of Σ(π) with respect to μ(2) yields the dominant contribution to the pion content, which is consistent with the d[over ¯]-u[over ¯] difference observed experimentally in the violation of the Gottfried sum rule.

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An analysis of the nucleon spectrum from lattice partially-quenched QCD

Cited by 17 publications

References 37 publications

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

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

Strange form factors of the nucleon with a nonlocal chiral effective Lagrangian

Taming the Pion Cloud of the Nucleon

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