Pion-nucleon scattering in a meson-exchange model

Gasparyan, A. M.; Haidenbauer, J.; Hanhart, C.; Speth, J.

doi:10.1103/physrevc.68.045207

Cited by 131 publications

(244 citation statements)

References 62 publications

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“…Indeed, such effects are predicted e.g. in the analysis of the EBAC group [73], whereas in the Jülich framework no such bare state is needed [422]. The result is interesting because it shows that a mutually consistent description of quark-core states for the nucleon and its first radial excitation is in principle possible in such models.…”

Section: Octet and Decuplet Baryonsmentioning

confidence: 71%

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: 71%

Baryons as relativistic three-quark bound states

Eichmann

Sanchis-Alepuz

Williams

et al. 2016

Progress in Particle and Nuclear Physics

436

530

View full text Add to dashboard Cite

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“…From the theory side, in order to describe such a fundamental process, dispersion relations for πN scattering have been investigated several decades ago [3][4][5] and many phenomenological models and different approaches have been proposed (see, e.g., refs. [6][7][8][9][10][11][12][13]). Roy-Steiner equations for the pion-nucleon scattering have been also analysed recently [14][15][16][17].…”

Section: Introductionmentioning

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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100

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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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“…For g σN N and m σ , their values can be found in many literatures on the nucleon-nucleon potential, and we list some of these [39][40][41][42] in the Tab. I, where we see there is about 20% difference between the values for g σN N and m σ .…”

Section: B Input Parameters For σ Intermediate State In T-channelmentioning

confidence: 99%