Poles of Karlsruhe-Helsinki KH80 and KA84 solutions extracted by using the Laurent-Pietarinen method

Švarc, Alfred; Hadžimehmedović, M.; Omerović, R.; Osmanović, H.; Stahov, J.

doi:10.1103/physrevc.89.045205

Cited by 32 publications

(46 citation statements)

References 19 publications

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“…Interestingly, not only values but also the errors of θ are in accordance with the experimental ones. Plots of amplitudes from L+P analysis18 are shown in Fig. 2, where we can see that the Breit-Wigner masses are fully consistent with equation (12).…”

Section: Resultssupporting

confidence: 59%

“…We plot the resulting amplitude phase in the complex plane in Fig. 3 and compare it to L+P amplitude from Švarc et al 18…”

Section: Resultsmentioning

confidence: 99%

“…We estimate its contribution using equation (6) with β = 0°, δ = −180°, Γ → 0 MeV, and x → ∞. We choose | r | = 59 MeV because with that value the amplitude at the real axis (its real and imaginary part) roughly resembles the realistic one in Švarc et al 18. close to N(1440).…”

Section: Resultsmentioning

confidence: 99%

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Fundamental properties of resonances

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Hadžimehmedović

Osmanović

et al. 2017

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All resonances, from hydrogen nuclei excited by the high-energy gamma rays in deep space to newly discovered particles produced in Large Hadron Collider, should be described by the same fundamental physical quantities. However, two distinct sets of properties are used to describe resonances: the pole parameters (complex pole position and residue) and the Breit-Wigner parameters (mass, width, and branching fractions). There is an ongoing decades-old debate on which one of them should be abandoned. In this study of nucleon resonances appearing in the elastic pion-nucleon scattering we discover an intricate interplay of the parameters from both sets, and realize that neither set is completely independent or fundamental on its own.

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Section: Resultssupporting

confidence: 59%

“…We plot the resulting amplitude phase in the complex plane in Fig. 3 and compare it to L+P amplitude from Švarc et al 18…”

Section: Resultsmentioning

confidence: 99%

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Fundamental properties of resonances

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Hadžimehmedović

Osmanović

et al. 2017

Sci Rep

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“…From scattering amplitudes we can use the LaurentPietarinen expansion [39][40][41][42] to extract the information about the S-matrix poles shown in Table I which offers a deeper insight into the mechanism of resonance formation. Notice that the pole in the S matrix emerges already before the critical value of g is reached.…”

Section: Solution Without Three-quark Resonant Statesmentioning

confidence: 99%

Genuine quark state versus dynamically generated structure for the Roper resonance

et al. 2018

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In view of the recent results of lattice QCD simulation in the P 11 partial wave that has found no clear signal for the three-quark Roper state we investigate a different mechanism for the formation of the Roper resonance in a coupled channel approach including the πN, π , and σ N channels. We fix the pion-baryon vertices in the underlying quark model while the s-wave sigma-baryon interaction is introduced phenomenologically with the coupling strength, the mass, and the width of the σ meson as free parameters. The Laurent-Pietarinen expansion is used to extract the information about the S-matrix pole. The Lippmann-Schwinger equation for the K matrix with a separable kernel is solved to all orders. For sufficiently strong σ NN coupling the kernel becomes singular and a quasibound state emerges at around 1.4 GeV, dominated by the σ N component and reflecting itself in a pole of the S matrix. The alternative mechanism involving a (1s) 2 2s quark resonant state is added to the model and the interplay of the dynamically generated state and the three-quark resonant state is studied. It turns out that for the mass of the three-quark resonant state above 1.6 GeV the mass of the resonance is determined solely by the dynamically generated state, nonetheless, the inclusion of the three-quark resonant state is imperative to reproduce the experimental width and the modulus of the resonance pole.

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“…In this paper, we use a Laurent (more precisely MittagLeffler [45]) method [46][47][48][49][50][51][52], called the L+P method, to separate the singularities and the regular parts. The background is represented by analytic functions with well defined cuts.…”

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confidence: 99%

Strong Evidence for Nucleon Resonances near 1900 MeV

et al. 2017

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Data on the reaction γp → K + Λ from the CLAS experiments are used to derive the leading multipoles, E0+, M1−, E1+, and M1+, from the production threshold to 2180 MeV in 24 slices of the invariant mass. The four multipoles are determined without any constraints. The multipoles are fitted using a multichannel L + P model which allows us to search for singularities and to extract the positions of poles on the complex energy plane in an almost model-independent method. The multipoles are also used as additional constraints in an energy-dependent analysis of a large body of pion and photo-induced reactions within the Bonn-Gatchina (BnGa) partial wave analysis. The study confirms the existence of poles due to nucleon resonances with spin-parity J P = 1/2 − ; 1/2 + , and 3/2 + in the region at about 1.9 GeV."Three quarks for Muster Mark" [1]. This sentence inspired Gell-Mann [2] to call quarks the three constituents of nucleons, of protons or neutrons. As a three-body system, the nucleon is expected to exhibit a large number of excitation modes. The most comprehensive predictions of the resonance excitation spectrum stem from quark-model calculations [3]-[8]; this predicted spectrum is qualitatively confirmed by recent Lattice QCD calculations [9], even though the quark masses used lead to a pion mass of 396 MeV. The predicted resonances may decay into a large variety of different decay modes. The most easily accessible was, for a long time, the πN decay of nucleon excitations by studying π ± p elastic scattering and the π − p → π 0 n charge exchange reaction. A large amount of data were analyzed by the groups at Karlsruhe-Helsinki (KH) [10], Carnegie-Mellon (CM) [11] and at GWU [12]. Real and imaginary parts of partial waves amplitudes with defined spin and parity (J P ) were extracted in slices of the πN invariant mass, and resonant contributions were identified. However, only a small fraction of the predicted energy levels has been observed experimentally, and for some of them, the evidence for their existence is only fair or even poor [13,14].The small number of observed excitations of the nucleon, as compared to quark model calculations, led to a number of speculations: Are nucleon resonances quarkdiquark oscillations with quasi-stable diquarks [15][16][17][18][19]) ? Are resonances generated by meson-baryon interactions [20][21][22][23][24][25], and are quarks and gluons misleading as degrees of freedom to interpret the excitation spectrum ? Does the mass-degeneracy of high-mass baryon resonances with positive and negative-parity hadron resonances indicate the onset of a new regime in which chiral symmetry is restored [26][27][28] ? At low excitation energy, chiral symmetry is strongly violated as indicated by the large mass gap between the nucleon mass (with spinparity J P = 1/2 + ) and its chiral partner N (1535) with [36]. The resonances stem from energydependent fits to the data. The resonances and the background contributions in all partial waves need to be determined in a single step. New data on γp → K +...

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Poles of Karlsruhe-Helsinki KH80 and KA84 solutions extracted by using the Laurent-Pietarinen method

Cited by 32 publications

References 19 publications

Fundamental properties of resonances

Fundamental properties of resonances

Genuine quark state versus dynamically generated structure for the Roper resonance

Strong Evidence for Nucleon Resonances near 1900 MeV

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