Instanton contributions to the low-lying hadron mass spectrum

Thomas, Samuel D.; Kamleh, Waseem; Leinweber, Derek B.

doi:10.1103/physrevd.92.094515

Cited by 6 publications

(6 citation statements)

References 63 publications

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“…While the ground state masses are slightly lower due to the use of smoothing [38], the qualitative features of the spectrum are intact, in agreement with results seen for the quark propagator [26,27]. In particular, the pion remains much lighter than the other mesons.…”

Section: Discussionsupporting

confidence: 84%

“…After a small amount of cooling, the vortex-only backgrounds are capable of recreating all the salient features of the low-lying hadron spectrum. While the ground state masses are slightly lower due to the use of smoothing [38], the qualitative features of the spectrum are intact, in agreement with results seen for the quark propagator [26,27]. In particular, the pion remains much lighter than the other mesons.…”

Section: Discussionsupporting

confidence: 84%

“…The vortex-only ensemble is able to reproduce all qualitative features of the spectrum, although masses are slightly lower. This is most likely an artifact of cooling [26,27,38]. Notably, in both cases the pion is much lighter than the rho, a clear signal that it retains its nature as a pseudo-Goldstone boson, and thus that dynamical chiral symmetry breaking is present on the vortex-only ensemble.…”

Section: Vortex-only Spectrummentioning

confidence: 94%

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Centre vortex removal restores chiral symmetry

Trewartha¹,

Kamleh²,

Leinweber³

2017

J. Phys. G: Nucl. Part. Phys.

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Abstract. The influence of centre vortices on dynamical chiral symmetry breaking is investigated through the light hadron spectrum on the lattice. Recent studies of the quark propagator and other quantities have provided evidence that centre vortices are the fundamental objects underpinning dynamical chiral symmetry breaking in SU (3) gauge theory. For the first time, we use the chiral overlap fermion action to study the low-lying hadron spectrum on lattice ensembles consisting of Monte Carlo, vortexremoved, and vortex-projected gauge fields. We find that gauge field configurations consisting solely of smoothed centre vortices are capable of reproducing all the salient features of the hadron spectrum, including dynamical chiral symmetry breaking. The hadron spectrum on vortex-removed fields shows clear signals of chiral symmetry restoration at light values of the bare quark mass, while at heavy masses the spectrum is consistent with a theory of weakly-interacting constituent quarks.

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Section: Discussionsupporting

confidence: 84%

Section: Discussionsupporting

confidence: 84%

Section: Vortex-only Spectrummentioning

confidence: 94%

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Centre vortex removal restores chiral symmetry

Trewartha¹,

Kamleh²,

Leinweber³

2017

J. Phys. G: Nucl. Part. Phys.

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“…Following the observation made in Ref. [32] that the number of overimproved stoutlink smearing sweeps is related to the gradient flow time by…”

Section: B Smoothingmentioning

confidence: 92%

Gluon propagator on a center-vortex background

2018

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The impact of SU (3) centre vortices on the gluon propagator in Landau gauge is investigated on original, vortex-removed and vortex-only lattice gauge field configurations. Vortex identification is found to partition the gluon propagator into short range strength on the vortex removed configurations and long range strength on the vortex only configurations. The effect of smoothing vortex-only configurations is also studied, and a regime for recovering the form of the smoothed original propagator from vortex-only configurations is introduced. The results reinforce the significance of centre vortices in a fundamental understanding of QCD vacuum structure.

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“…The conserved quantum numbers of a symmetry group are determined using the little group, which for SO(3) and O h depend on the momenta type[35]. In this study we focus on states at rest.…”

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confidence: 99%

Searching for beauty-fully bound tetraquarks using lattice nonrelativistic QCD

2018

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Motivated by multiple phenomenological considerations, we perform the first search for the existence of abbbb tetraquark bound state with a mass below the lowest noninteracting bottomonium-pair threshold using the first-principles lattice nonrelativistic QCD methodology. We use a full S-wave color/spin basis for thebbbb operators in the three 0 þþ , 1 þ− and 2 þþ channels. We employ four gluon field ensembles at multiple lattice spacing values ranging from a ¼ 0.06-0.12 fm, all of which include u, d, s and c quarks in the sea, and one ensemble which has physical light-quark masses. Additionally, we perform novel exploratory work with the objective of highlighting any signal of a near threshold tetraquark, if it existed, by adding an auxiliary potential into the QCD interactions. With our results we find no evidence of a QCD bound tetraquark below the lowest noninteracting thresholds in the channels studied.

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Instanton contributions to the low-lying hadron mass spectrum

Cited by 6 publications

References 63 publications

Centre vortex removal restores chiral symmetry

Centre vortex removal restores chiral symmetry

Gluon propagator on a center-vortex background

Searching for beauty-fully bound tetraquarks using lattice nonrelativistic QCD

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