A dispersive treatment of Kℓ₄ decays

Stoffer, Peter; Colangelo, Gilberto; Passemar, Emilie (27 March 2017). A dispersive treatment of Kℓ₄ decays. Journal of Physics: Conference Series, 800(1), 012026. Institute of Physics Publishing IOP 10.1088/1742-6596/800/1/012026

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Kℓ₄ decays have several features of interest: they allow an accurate measurement of ππ -scattering lengths; the decay is the best source for the determination of some low-energy constants of chiral perturbation theory (χPT); one form factor of the decay is connected to thechiral anomaly. We present the results of our dispersive analysis of Kℓ₄ decays, which provides a resummation of ππ- and Kπ-rescattering effects. The free parameters of the dispersion relation are fitted to the data of the high-statistics experiments E865 and NA48/2. By matching to χPT at NLO and NNLO, we determine the low-energy constants Lr1, Lr2 and Lr3. In contrast to a pure chiral treatment, the dispersion relation describes the observed curvature of one of the Kℓ₄ form factors, which we understand as an effect of rescattering beyond NNLO.

Item Type:

Conference or Workshop Item (Paper)

Division/Institute:

10 Strategic Research Centers > Albert Einstein Center for Fundamental Physics (AEC)
08 Faculty of Science > Institute of Theoretical Physics

UniBE Contributor:

Stoffer, Peter; Colangelo, Gilberto and Passemar, Emilie

Subjects:

500 Science > 530 Physics

ISSN:

1742-6588

Publisher:

Institute of Physics Publishing IOP

Language:

English

Submitter:

Esther Fiechter

Date Deposited:

03 Nov 2017 10:14

Last Modified:

03 Nov 2017 10:14

Publisher DOI:

10.1088/1742-6596/800/1/012026

BORIS DOI:

10.7892/boris.102042

URI:

https://boris.unibe.ch/id/eprint/102042

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