Chiral symmetry and the near-threshold pion-induced 2π production on the nucleon

Jäkel, Oliver; Dillig, M.; Vasconcellos, C. A. Z.

doi:10.1016/0375-9474(92)90227-b

Cited by 18 publications

(6 citation statements)

References 11 publications

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“…There is such a candidate at the energies where we are concerned which is the N * (1440) Roper resonance. The branching ratio for this decay is small but it plays a very important role in the πN → ππN reaction [54,55,56,57,58]. It has also been shown that this mechanism is the dominant in the NN → NNππ reaction close to threshold [59,60].…”

Section: Roper-hole Excitationmentioning

confidence: 98%

Renormalization of the and scalar resonances in a nuclear medium

Oset

Vacas

2000

Nuclear Physics A

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The meson meson interaction in the scalar sector in the presence of a nuclear medium is studied with particular attention to the change of the properties of the f 0 (980) and a 0 (980) resonances. By using a chiral unitary approach which generates the f 0 and a 0 resonances and reproduces their free properties, we find that the position of the resonances in the medium is barely changed but their widths are considerably broadened. New many body corrections generating from higher orders in the chiral Lagrangian plus the contribution from N*h excitations, not considered before in connection with the ππ interaction in the nuclear medium, are also investigated.

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Section: Roper-hole Excitationmentioning

confidence: 98%

Renormalization of the and scalar resonances in a nuclear medium

Oset

Vacas

2000

Nuclear Physics A

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“…A number of theoretical investigations of πN → ππN reactions have been performed using (1) tree-diagram calculations [17,18,19,20,21,22,23], (2) chiral perturbation theory [24,25,26,27], and (3)tree-diagram calculations including coupled-channels effects on nucleon resonances [28]. To see the scope of our investigation, it is useful to give a brief review of these previous works in the following subsections.…”

Section: Introductionmentioning

confidence: 99%

Dynamical coupled-channels study of pi N --> pi pi N reactions

Kamano,

Julia-Diaz,

Lee

et al. 2008

Preprint

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As a step toward performing a complete coupled-channels analysis of the world data of πN, γ * N → πN, ηN, ππN reactions, the πN → ππN reactions are investigated starting with the dynamical coupled-channels model developed in Phys. Rev. C76, 065201 (2007). The channels included are πN , ηN , and ππN which has π∆, ρN , and σN resonant components. The non-resonant amplitudes are generated from solving a set of coupled-channels equations with the meson-baryon potentials defined by effective Lagrangians. The resonant amplitudes are generated from 16 bare excited nucleon (N * ) states which are dressed by the non-resonant interactions as constrained by the unitarity condition. The data of total cross sections and πN and ππ invariant mass distributions of π + p → π + π + n, π + π 0 p and π − p → π + π − n, π − π 0 p, π 0 π 0 n reactions from threshold to the invariant mass W = 2 GeV can be described to a very large extent. We show the importance of the coupled-channels effects and the strong interference between the contributions from the π∆, σN , and ρN channels. The large interference between the resonant and non-resonant amplitudes is also demonstrated. Possible future developments are discussed.

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“…This has been done by Jensen and Miranda [17] and by Kammano and Arima [18] and in resonance models like e.g. [19,20,21,22]. Such an approach makes sense if one checks that at low energies the chiral perturbation theory results are recovered or if one enforces this behaviour through explicit matching of the pertinent amplitudes.…”

Section: Introductionmentioning

confidence: 99%