Hadron masses and the sigma commutator in light of chiral perturbation theory

Gasser, J.

doi:10.1016/0003-4916(81)90086-5

Cited by 209 publications

(226 citation statements)

References 58 publications

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“…The strange contribution to the nucleon mass is < p|m ss s|p >= 150 ± 50 MeV which translates into the strangeness fraction y = 0.25±0.05 andσ = 33±3 MeV. The results are in good agreement with previous calculations [6,7]. While a definite statement about the convergence of the chiral expansions for the σ-terms cannot be made in dimensional regularization, there is a clear convergence in the cutoff scheme.…”

Section: Discussionsupporting

confidence: 86%

Sigma-terms in heavy baryon chiral perturbation theory revisited

Borasoy

1999

Eur. Phys. J. C

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The σ-terms are calculated at next-to-leading order in heavy baryon chiral perturbation theory by employing a cutoff regularization. The results do not depend on the cutoff value to the order we are working . The baryon masses and σ πN (0) are used to perform a least-squares fit to the three appearing low-energy constants and predictions for the two KN σ-terms and the strange contribution to the nucleon mass are made. The lack of convergence in the chiral expansions of these quantities when regularized dimensionally is overcome in the cutoff scheme. The σ-term shifts to the pertinent Cheng-Dashen points are calculated. We also include the spin-3/2 decuplet in the effective theory.

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Section: Discussionsupporting

confidence: 86%

Sigma-terms in heavy baryon chiral perturbation theory revisited

Borasoy

1999

Eur. Phys. J. C

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“…[15,80,81], and of the strangeness content, see refs. [83][84][85][86] for instance. A high-precision determination of the σ πN was done from RS-equation analysis based on the improved Cheng-Dashen low-energy theorem and σ πN = (59.1 ± 3.5) MeV was reported in ref.…”

Section: Baryon Sigma Terms and The Strangeness Content Of The Nucleonmentioning

confidence: 99%

Pion-nucleon scattering in covariant baryon chiral perturbation theory with explicit Delta resonances

Yao

Siemens

Bernard

et al. 2016

J. High Energ. Phys.

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We present the results of a third order calculation of the pion-nucleon scattering amplitude in a chiral effective field theory with pions, nucleons and delta resonances as explicit degrees of freedom. We work in a manifestly Lorentz invariant formulation of baryon chiral perturbation theory using dimensional regularization and the extended on-mass-shell renormalization scheme. In the delta resonance sector, the on mass-shell renormalization is realized as a complex-mass scheme. By fitting the low-energy constants of the effective Lagrangian to the S-and P -partial waves a satisfactory description of the phase shifts from the analysis of the Roy-Steiner equations is obtained. We predict the phase shifts for the D and F waves and compare them with the results of the analysis of the George Washington University group. The threshold parameters are calculated both in the delta-less and delta-full cases. Based on the determined low-energy constants, we discuss the pion-nucleon sigma term. Additionally, in order to determine the strangeness content of the nucleon, we calculate the octet baryon masses in the presence of decuplet resonances up to next-to-next-to-leading order in SU(3) baryon chiral perturbation theory. The octet baryon sigma terms are predicted as a byproduct of this calculation.

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“…A possible resolution is that the variation of the π-N amplitude from the Cheng-Dashen point t = 2µ 2 to t = 0, where the σ term (1) is defined, is substantial, resulting in a smaller value σ ≈ 45MeV [3]. Combined with the suggestion [4] that one-loop chiral perturbative corrections raises the value of σ 0 to σ 0 = 35MeV, this would imply a more reasonable value y ≈ 0.2 of the nucleon strangeness content.…”

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confidence: 99%

Pion-nucleon σ term in lattice QCD

et al. 1995

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We calculate both connected and disconnected contribution to the π-N σ-term in quenched lattice QCD with Wilson quark action on a 12 3 × 20 lattice at β = 5.7. The latter is evaluated with the aid of the variant wall source method, which was previously applied successfully for extraction of π-π scattering lengths and η ′ meson mass. We found that the disconnected contribution is about twice larger than the connected one. The value for the full π-N σ term σ = 40 − 60 MeV is consistent with the experimental estimates. The nucleon matrix element of the strange quark densityss is fairly large in our result.

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Hadron masses and the sigma commutator in light of chiral perturbation theory

Cited by 209 publications

References 58 publications

Sigma-terms in heavy baryon chiral perturbation theory revisited

Sigma-terms in heavy baryon chiral perturbation theory revisited

Pion-nucleon scattering in covariant baryon chiral perturbation theory with explicit Delta resonances

Pion-nucleon σ term in lattice QCD

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