Author:
,Batley J. R.,Kalmus G.,Lazzeroni C.,Munday D. J.,Slater M. W.,Wotton S. A.,Arcidiacono R.,Bocquet G.,Cabibbo N.,Ceccucci A.,Cundy D.,Falaleev V.,Fidecaro M.,Gatignon L.,Gonidec A.,Kubischta W.,Maier A.,Norton A.,Patel M.,Peters A.,Monnier E.,Swallow E.,Winston R.,Rubin P.,Walker A.,Dalpiaz P.,Damiani C.,Fiorini M.,Martini M.,Petrucci F.,Savrié M.,Scarpa M.,Wahl H.,Baldini W.,Cotta Ramusino A.,Gianoli A.,Calvetti M.,Celeghini E.,Iacopini E.,Lenti M.,Ruggiero G.,Bizzeti A.,Veltri M.,Behler M.,Eppard K.,Hita-Hochgesand M.,Kleinknecht K.,Marouelli P.,Masetti L.,Moosbrugger U.,Morales Morales C.,Renk B.,Wache M.,Wanke R.,Winhart A.,Coward D.,Dabrowski A.,Fonseca Martin T.,Shieh M.,Szleper M.,Velasco M.,Wood M. D.,Anzivino G.,Imbergamo E.,Nappi A.,Piccini M.,Raggi M.,Valdata-Nappi M.,Cenci P.,Pepe M.,Petrucci M. C.,Costantini F.,Doble N.,Fiorini L.,Giudici S.,Pierazzini G.,Sozzi M.,Venditti S.,Collazuol G.,Di Lella L.,Lamanna G.,Mannelli I.,Michetti A.,Cerri C.,Fantechi R.,Bloch-Devaux B.,Cheshkov C.,Chèze J. B.,De Beer M.,Derré J.,Marel G.,Mazzucato E.,Peyaud B.,Vallage B.,Holder M.,Ziolkowski M.,Bifani S.,Clemencic M.,Goy Lopez S.,Biino C.,Cartiglia N.,Marchetto F.,Dibon H.,Jeitler M.,Markytan M.,Mikulec I.,Neuhofer G.,Widhalm L.,Balev S.,Frabetti P. L.,Gersabeck E.,Goudzovski E.,Hristov P.,Kekelidze V.,Korotkova A.,Kozhuharov V.,Litov L.,Madigozhin D.,Molokanova N.,Polenkevich I.,Potrebenikov Yu.,Stoynev S.,Zinchenko A.
Abstract
Abstract
The NA48/2 experiment at CERN reports the first observation of the K± → π0π0μ±ν decay based on a sample of 2437 candidates with 15% background contamination collected in 2003–2004. The decay branching ratio in the kinematic region of the squared dilepton mass above 0.03 GeV2/c4 is measured to be (0.65 ± 0.03) × 10−6. The extrapolation to the full kinematic space, using a specific model, is found to be (3.45 ± 0.16) × 10−6, in agreement with chiral perturbation theory predictions.
Publisher
Springer Science and Business Media LLC
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