Colangelo, Gilberto; Passemar, Emilie; Stoffer, Peter (2015). A dispersive treatment of K ℓ 4 decays. European physical journal. C - particles and fields, 75(4) EDP Sciences 10.1140/epjc/s10052-015-3357-1
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Kℓ4 decays have several features of interest: they allow an accurate measurement of ππ-scattering lengths; they provide the best source for the determination of some low-energy constants of χPT; one form factor is directly related to the chiral anomaly, which can be measured here. We present a dispersive treatment of Kℓ4 decays that 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. The matching to χPT at NLO and NNLO enables us to determine the LECs Lr1, Lr2 and Lr3. With recently published data from NA48/2, the LEC Lr9 can be determined as well. In contrast to a pure chiral treatment, the dispersion relation describes the observed curvature of one of the form factors, which we understand as a rescattering effect beyond NNLO.
Item Type: |
Journal Article (Original Article) |
|---|---|
Division/Institute: |
10 Strategic Research Centers > Albert Einstein Center for Fundamental Physics (AEC) 08 Faculty of Science > Institute of Theoretical Physics |
UniBE Contributor: |
Colangelo, Gilberto, Passemar, Emilie, Stoffer, Peter |
Subjects: |
500 Science > 530 Physics |
ISSN: |
1434-6044 |
Publisher: |
EDP Sciences |
Language: |
English |
Submitter: |
Esther Fiechter |
Date Deposited: |
31 Aug 2015 17:11 |
Last Modified: |
05 Dec 2022 14:49 |
Publisher DOI: |
10.1140/epjc/s10052-015-3357-1 |
BORIS DOI: |
10.7892/boris.71428 |
URI: |
https://boris.unibe.ch/id/eprint/71428 |
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