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Pion-pion scattering amplitude. IV. Improved analysis with once subtracted Roy-like equations up to 1100 MeV



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Garcia-Martin, R. and Kamiński, Robert and Peláez Sagredo, José Ramón and Ruiz de Elvira, Jacobo and Yndurain, F.J. (2011) Pion-pion scattering amplitude. IV. Improved analysis with once subtracted Roy-like equations up to 1100 MeV. Physical review D, 83 . ISSN 1550-7998

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Official URL: http://dx.doi.org/10.1103/PhysRevD.83.074004


We improve our description of π π scattering data by imposing additional requirements on our previous fits, in the form of once-subtracted Roy-like equations, while extending our analysis up to 1100 MeV. We provide simple and ready to use parametrizations of the amplitude. In addition, we present a detailed description and derivation of these once-subtracted dispersion relations that, in the 450 to 1100 MeV region, provide an additional constraint which is much stronger than our previous requirements of forward dispersion relations and standard Roy equations. The ensuing constrained amplitudes describe the existing data with rather small uncertainties in the whole region from threshold up to 1100 MeV, while satisfying very stringent dispersive constraints. For the S0 wave, this requires an improved matching of the low and high energy parametrizations. Also for this wave we have considered the latest low energy K_(l4) decay results, including their isospin violation correction, and we have removed some controversial data points. These changes on the data translate into better determinations of threshold and subthreshold parameters which remove almost alldisagreement with previous chiral perturbation theory and Roy equation calculations below 800 MeV. Finally, our results favor the dip structure of the S0 inelasticity around the controversial 1000 MeV region.

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©2011 American Physical Society.
At the early stages of this collaboration, we suffered the devastating loss of one of the authors, F. J. Ynduraín, whose contributions were essential for this work. He was an example of humanity and scientific dedication. We also thank I. Caprini, G. Colangelo, J. Gasser, and H. Leutwyler for many discussions and suggestions on possible improvements of our parametrizations, as well as D. V. Bugg for comments on the S0 wave inelasticity, and B. Kubis for his comments on K3 decays. This work is partly supported by DGICYT Contracts No. FIS2006-03438 and No. FPA2005-02327, Santander/Complutense Contract No. PR27/05-13955-BSCH and the EU Integrated Infrastructure Initiative Hadron Physics Project under Contract No. RII3-CT-2004-506078.

Uncontrolled Keywords:Phase-sift analysis; Chiral perturbation-theory; Gev-C; Extraordinary hadrons; Momentum-transfer; π π mplitudes; High statistics; Decays; Region; π& π
Subjects:Sciences > Physics > Physics-Mathematical models
Sciences > Physics > Mathematical physics
ID Code:35008
Deposited On:14 Jan 2016 16:30
Last Modified:10 Dec 2018 15:09

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