Global analysis of π<i>N</i>→ππ<i>N</i>data near threshold and chiral-symmetry breaking

Burkhardt, Hugh; Lowe, J.

doi:10.1103/physrevlett.67.2622

Cited by 38 publications

(44 citation statements)

References 27 publications

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“…[18,64] where the authors have stated that the database on total cross sections is internally consistent up to p lab = 400MeV /c (apart from a momentum region 310 − 370MeV /c in the π + π + n-channel). It is interesting to elaborate on this aspect in more detail.…”

Section: Results Of the Fitmentioning

confidence: 99%

“…[18,64] points nn. 73, 75 have been omitted along with those quoted above, while near threshold points nn.…”

Section: Results Of the Fitmentioning

confidence: 99%

“…The same is true for the πNN vertex also. We use the familiar pseudovector type (18). This note also explains the absence of the terms with the derivative of the nucleon field in (21) -such a term could again only renormalize the parameters already taken into account.…”

Section: The ∆ Contributionmentioning

confidence: 99%

“…The effective Lagrangians (18)(19)(20)(21) describe the ∆ contribution to the πN → ππN amplitude (in the energy region under consideration) in the most general way. They contain 6 real free parameters (g πN ∆ , g π∆∆ , f 0 , f 1 , g 0 , g 1 ), one of them (g πN ∆ ) can be fixed in accordance with the known ∆ → πN decay width.…”

Section: The ∆ Contributionmentioning

confidence: 99%

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Analysis of data on low energy πN → ππN reaction I. Total cross sections

et al. 1995

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This is the first of a series of papers on a consistent model independent analysis of the complete experimental information on the reaction πN → ππN at pion momenta up to 500 MeV/c. The paper summarizes the theoretical approach and details of the computational procedure. The complete database on total cross sections in 5 ππN channels is given together with a critical discussion of their model independent analysis. * This work was funded by the Deutsche Forschungsgemeinschaft (DFG), Bundesminister für Forschung und Technologie (BMFT), and the Kernforschungsanlage Jülich (KFA) and Russian Ministry of Education Grant G13.018 0

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Section: Results Of the Fitmentioning

confidence: 99%

“…[18,64] points nn. 73, 75 have been omitted along with those quoted above, while near threshold points nn.…”

Section: Results Of the Fitmentioning

confidence: 99%

Section: The ∆ Contributionmentioning

confidence: 99%

Section: The ∆ Contributionmentioning

confidence: 99%

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Analysis of data on low energy πN → ππN reaction I. Total cross sections

et al. 1995

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“…It should be noted, that before the OMICRON measurements [41]- [44] only the {− + n} channel allowed to obtain the definite results of the linear fit; the above mentioned OMICRON data provided the possibility to carry out the procedure also for the {− 0 p} and {+ + n} channels. The authors of the paper [27] took advantage of the precise data [53] on the σ {00n} (very close to threshold) and provided the simultaneous linear fit of all channels.…”

Section: Databasementioning

confidence: 99%

Phenomenological πN→ππN amplitude and analysis of low energy data on total cross sections and 1--D distributions

Bolokhov

Polyakov²,

Sherman³

1998

EPJ A

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We develop the phenomenological amplitude of the πN → ππN reaction describing the exchanges of ∆ and N * along with the OPE mechanism. The contribution of the latter contains 4 independent low energy parameters (up to O(k 4 ) order). The terms of the polynomial background are added to stand for far resonances and for contact terms originating from the off-mass-shell interactions. These terms are introduced with the account of isotopic, crossing, C, P and T symmetries of strong interactions.The data consisting of total cross sections in the energy region 0.300 ≤ P Lab ≤ 500 MeV/c and 1D distributions from the bubble-chamber experiments for three reaction channels were undergoing fittings to determine free parameters of the amplitude. The best solutions are characterized by χ 2 DF = 1.16. At the considered energies the isobar exchanges are found to be more important than OPE. The obtained solutions reveal the need in more precise data and/or in polarization measurements because of large correlations of isobar parameters with the OPE ones.The theoretical solutions were used for modeling the Chew-Low extrapolation and the Olsson-Turner threshold approach. It is shown that the noncritical application of the former results in 100% theoretical errors, the extracted values being in fact the random numbers. The results of the Olsson-Turner method are characterized by significant systematic errors coming from unknown details of isobar physics. Sankt-Petersburg 1997

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Summary of π-π scattering experiments

Počanić

Chiral Dynamics: Theory and Experiment

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The ππ scattering amplitude at threshold is fully determined by the chiral symmetry breaking part of the strong interaction, and, thus, directly constrains the form of the low energy effective lagrangians. Current status of the study of the low energy ππ interaction is discussed, particularly the recent results on reactions πN → ππN near threshold. Present levels of experimental uncertainties and limitations inherent to the available analysis methods leave ample room for improvements in the determination of the s-wave ππ scattering lengths. Experimental improvements are expected from new measurements of K e4 decays and from attempts to study π + π − atoms, while further theoretical work is required in order to make full use of the extensive near-threshold πN → ππN data that has recently become available.

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Global analysis of πN→ππNdata near threshold and chiral-symmetry breaking

Cited by 38 publications

References 27 publications

Analysis of data on low energy πN → ππN reaction I. Total cross sections

Analysis of data on low energy πN → ππN reaction I. Total cross sections

Phenomenological πN→ππN amplitude and analysis of low energy data on total cross sections and 1--D distributions

Summary of π-π scattering experiments

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