Measurements of charged kaon semileptonic decay branching fractions K±→π0μ±ν and K±→π0e±ν and their ratio

J.R. Batley; C. Lazzeroni; D.J. Munday; M.W. Slater; S.A. Wotton; R. Arcidiacono; G. Bocquet; N. Cabibbo; A. Ceccucci; D. Cundy; V. Falaleev; M. Fidecaro; L. Gatignon; A. Gonidec; W. Kubischta; A. Norton; M. Patel; A. Peters; S. Balev; P.L. Frabetti; E. Goudzovski; P. Hristov; V. Kozhuharov; L. Litov; D. Madigozhin; E. Marinova; N. Molokanova; I. Polenkevich; Y. Potrebenikov; S. Stoynev; A. Zinchenko; E. Monnier; E. Swallow; R. Winston; P. Rubin; A. Walker; W. Baldini; A. Cotta Ramusino; P. Dalpiaz; C. Damiani; M. Fiorini; A. Gianoli; M. Martini; F. Petrucci; M. Savrié; M. Scarpa; H. Wahl; A. Bizzeti; M. Calvetti; E. Celeghini; E. Iacopini; M. Lenti; F. Martelli; G. Ruggiero; M. Veltri; M. Behler; K. Eppard; K. Kleinknecht; P. Marouelli; L. Masetti; U. Moosbrugger; C. Morales Morales; B. Renk; M. Wache; R. Wanke; A. Winhart; D. Coward; A. Dabrowski; T. Fonseca Martin; M. Shieh; M. Szleper; M. Velasco; M.D. Wood; G. Anzivino; P. Cenci; E. Imbergamo; M. Pepe; M.C. Petrucci; M. Piccini; M. Raggi; M. Valdata-Nappi; C. Cerri; G. Collazuol; F. Costantini; L. DiLella; N. Doble; R. Fantechi; L. Fiorini; S. Giudici; G. Lamanna; I. Mannelli; A. Michetti; G. Pierazzini; M. Sozzi; B. Bloch-Devaux; C. Cheshkov; J.B. Chèze; M. De Beer; J. Derré; G. Marel; E. Mazzucato; B. Peyaud; B. Vallage; M. Holder; A. Maier; M. Ziolkowski; S. Bifani; C. Biino; N. Cartiglia; M. Clemencic; S. Goy Lopez; F. Marchetto; H. Dibon; M. Jeitler; M. Markytan; I. Mikulec; G. Neuhofer; L. Widhalm

doi:10.1140/epjc/s10052-007-0253-3

2023 Impact factor 4.2

Particles and Fields

This article has an erratum: [https://doi.org/10.1140/epjc/s10052-007-0454-9]

Eur. Phys. J. C (2007) 50: 329-340
https://doi.org/10.1140/epjc/s10052-007-0253-3

Regular Article - Experimental Physics

Measurements of charged kaon semileptonic decay branching fractions K^±→π⁰μ^±ν and K^±→π⁰e^±ν and their ratio

J.R. Batley¹, C. Lazzeroni¹, D.J. Munday¹, M.W. Slater¹, S.A. Wotton¹, R. Arcidiacono², G. Bocquet², N. Cabibbo², A. Ceccucci², D. Cundy², V. Falaleev², M. Fidecaro², L. Gatignon², A. Gonidec², W. Kubischta², A. Norton², M. Patel², A. Peters², S. Balev³, P.L. Frabetti³, E. Goudzovski³, P. Hristov³, V. Kozhuharov³, L. Litov³, D. Madigozhin³, E. Marinova³, N. Molokanova³, I. Polenkevich³, Y. Potrebenikov³, S. Stoynev³, A. Zinchenko³, E. Monnier⁴^,16, E. Swallow⁴, R. Winston⁴, P. Rubin⁵, A. Walker⁵, W. Baldini⁶, A. Cotta Ramusino⁶, P. Dalpiaz⁶, C. Damiani⁶, M. Fiorini⁶, A. Gianoli⁶, M. Martini⁶, F. Petrucci⁶, M. Savrié⁶, M. Scarpa⁶, H. Wahl⁶, A. Bizzeti⁷^,17, M. Calvetti⁷, E. Celeghini⁷, E. Iacopini⁷, M. Lenti⁷, F. Martelli⁷^,18, G. Ruggiero⁷, M. Veltri⁷^,18, M. Behler⁸, K. Eppard⁸, K. Kleinknecht⁸, P. Marouelli⁸, L. Masetti⁸, U. Moosbrugger⁸, C. Morales Morales⁸, B. Renk⁸, M. Wache⁸, R. Wanke⁸, A. Winhart⁸, D. Coward⁹, A. Dabrowski⁹, T. Fonseca Martin⁹, M. Shieh⁹, M. Szleper⁹, M. Velasco⁹^*, M.D. Wood⁹, G. Anzivino¹⁰, P. Cenci¹⁰, E. Imbergamo¹⁰, M. Pepe¹⁰, M.C. Petrucci¹⁰, M. Piccini¹⁰, M. Raggi¹⁰, M. Valdata-Nappi¹⁰, C. Cerri¹¹, G. Collazuol¹¹, F. Costantini¹¹, L. DiLella¹¹, N. Doble¹¹, R. Fantechi¹¹, L. Fiorini¹¹, S. Giudici¹¹, G. Lamanna¹¹, I. Mannelli¹¹, A. Michetti¹¹, G. Pierazzini¹¹, M. Sozzi¹¹, B. Bloch-Devaux¹², C. Cheshkov¹², J.B. Chèze¹², M. De Beer¹², J. Derré¹², G. Marel¹², E. Mazzucato¹², B. Peyaud¹², B. Vallage¹², M. Holder¹³, A. Maier¹³, M. Ziolkowski¹³, S. Bifani¹⁴, C. Biino¹⁴, N. Cartiglia¹⁴, M. Clemencic¹⁴, S. Goy Lopez¹⁴, F. Marchetto¹⁴, H. Dibon¹⁵, M. Jeitler¹⁵, M. Markytan¹⁵, I. Mikulec¹⁵, G. Neuhofer¹⁵, L. Widhalm¹⁵ and The NA48/2 Collaboration

¹ Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK
² CERN, 1211, Geneva 23, Switzerland
³ Joint Institute for Nuclear Research, Dubna, Russian Federation
⁴ The Enrico Fermi Institute, The University of Chicago, Chicago, IL, 60126, USA
⁵ Department of Physics and Astronomy, University of Edinburgh, JCMB King’s Buildings, Mayfield Road, Edinburgh, EH9 3JZ, UK
⁶ Dipartimento di Fisica dell’Università e Sezione dell’INFN di Ferrara, 44100, Ferrara, Italy
⁷ Dipartimento di Fisica dell’Università e Sezione dell’INFN di Firenze, 50125, Firenze, Italy
⁸ Institut für Physik, Universität Mainz, 55099, Mainz, Germany
⁹ Department of Physics and Astronomy, Northwestern University , Evanston, IL, 60208-3112, USA
¹⁰ Dipartimento di Fisica dell’Università e Sezione dell’INFN di Perugia, 06100, Perugia, Italy
¹¹ Dipartimento di Fisica, Scuola Normale Superiore e Sezione dell’INFN di Pisa, 56100, Pisa, Italy
¹² DSM/DAPNIA – CEA Saclay, 91191, Gif-sur-Yvette, France
¹³ Fachbereich Physik, Universität Siegen, 57068, Siegen, Germany
¹⁴ Dipartimento di Fisica Sperimentale dell’Università e, Sezione dell’INFN di Torino, 10125, Torino, Italy
¹⁵ Institut für Hochenergiephysik, Österreichische Akademie der Wissenschaften, 10560, Wien, Austria
¹⁶ Centre de Physique des Particules de Marseille, IN2P3-CNRS ,Université de la Méditerranée, Marseille, France
¹⁷ Dipartimento di Fisica, Università di Modena, 41100, Modena, Italy
¹⁸ Istituto di Fisica, Università di Urbino, 61029, Urbino, Italy

^* e-mail: mvelasco@lotus.phys.northwestern.edu

Received: 22 December 2006
Revised: 6 February 2007
Published online: 13 March 2007

Abstract

Measured ratios of decay rates for ${\mathcal{R}}_{K e 3 / K2\pi}$ , ${\mathcal{R}}_{K \mu3 / K2\pi}$ and ${\mathcal{R}}_{K \mu3 / Ke3}$ are presented. These measurements are based on K^± decays collected in a dedicated run in 2003 by the NA48/2 experiment at CERN. The results obtained are ${\mathcal{R}}_{K e 3 / K2\pi} = 0.2496\pm0.0009 ({\text{stat}})\pm0.0004 ({\text{syst}})$ and ${\mathcal{R}}_{K \mu3 / K2\pi} = 0.1637\pm0.0006 ({\text{stat}})\pm0.0003 ({\text{syst}})$ . Using the PDG average for the K^±→π^±π⁰ normalisation mode, both values are found to be larger than the current values given by the particle data book and lead to a larger magnitude of the |V_us| CKM element than previously accepted. When combined with the latest particle data book value of |V_ud|, the result is in agreement with unitarity of the CKM matrix. In addition, a new measured value of ${\mathcal{R}}_{K \mu3 / Ke3} = 0.656\pm0.003({\text{stat}})\pm0.001({\text{syst}})$ is compared to the semi-empirical predictions based on the latest form factor measurements.

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