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arXiv · 2310.20295

First observation and study of the $K^{\pm} \rightarrow \pi^{0} \pi^{0} \mu^{\pm} \nu$ decay

2 Collaboration·J. R. Batley·G. Kalmus·C. Lazzeroni·D. J. Munday·M. W. Slater·S. A. Wotton·R. Arcidiacono·A. Ceccucci·G. Bocquet·N. Cabibbo·D. Cundy·V. Falaleev·L. Gatignon·M. Fidecaro·A. Gonidec·W. Kubischta·A. Maier·A. Norton·M. Patel·A. Peters·S. Balev·P. L. Frabetti·E. Gersabeck·E. Goudzovski·P. Hristov·V. Kekelidze·D. Madigozhin·N. Molokanova·I. Polenkevich·Yu. Potrebenikov·A. Korotkova·S. Stoynev·A. Zinchenko·V. Kozhuharov·L. Litov·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. Veltri·M. Calvetti·E. Celeghini·E. Iacopini·M. Lenti·G. Ruggiero·M. Behler·K. Eppard·M. Hita-Hochgesand·K. Kleinknecht·P. Marouelli·L. Masetti·U. Moosbrugger·C. Morales Morales·B. Renk·M. Wache·A. Winhart·R. Wanke·D. Coward·A. Dabrowski·T. Fonseca Martin·M. Shieh·M. Szleper·M. Velasco·M. D. Wood·P. Cenci·M. Pepe·M. C. Petrucci·G. Anzivino·E. Imbergamo·A. Nappi·M. Piccini·M. Raggi·M. Valdata-Nappi·C. Cerri·R. Fantechi·G. Collazuol·L. Di Lella·G. Lamanna·I. Mannelli·A. Michetti·F. Costantini·N. Doble·L. Fiorini·S. Giudici·G. Pierazzini·M. Sozzi
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Abstract

The NA48/2 experiment at CERN reports the first observation of the $K^{\pm} \rightarrow \pi^{0} \pi^{0} \mu^{\pm} \nu$ 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 $0.03$~GeV$^2/c^4$ is measured to be $(0.65 \pm 0.03) \times 10^{-6}$. The extrapolation to the full kinematic space, using a specific model, is found to be $(3.45 \pm 0.16) \times 10^{-6}$, in agreement with chiral perturbation theory predictions.

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2 Collaboration, J. R. Batley, G. Kalmus, C. Lazzeroni, D. J. Munday, M. W. Slater, S. A. Wotton, R. Arcidiacono, A. Ceccucci, G. Bocquet, N. Cabibbo, D. Cundy, V. Falaleev, L. Gatignon, M. Fidecaro, A. Gonidec, W. Kubischta, A. Maier, A. Norton, M. Patel, A. Peters, S. Balev, P. L. Frabetti, E. Gersabeck, E. Goudzovski, P. Hristov, V. Kekelidze, D. Madigozhin, N. Molokanova, I. Polenkevich, Yu. Potrebenikov, A. Korotkova, S. Stoynev, A. Zinchenko, V. Kozhuharov, L. Litov, 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. Veltri, M. Calvetti, E. Celeghini, E. Iacopini, M. Lenti, G. Ruggiero, M. Behler, K. Eppard, M. Hita-Hochgesand, K. Kleinknecht, P. Marouelli, L. Masetti, U. Moosbrugger, C. Morales Morales, B. Renk, M. Wache, A. Winhart, R. Wanke, D. Coward, A. Dabrowski, T. Fonseca Martin, M. Shieh, M. Szleper, M. Velasco, M. D. Wood, P. Cenci, M. Pepe, M. C. Petrucci, G. Anzivino, E. Imbergamo, A. Nappi, M. Piccini, M. Raggi, M. Valdata-Nappi, C. Cerri, R. Fantechi, G. Collazuol, L. Di Lella, G. Lamanna, I. Mannelli, A. Michetti, F. Costantini, N. Doble, L. Fiorini, S. Giudici, G. Pierazzini, M. Sozzi. 2023-10-31. First observation and study of the $K^{\pm} \rightarrow \pi^{0} \pi^{0} \mu^{\pm} \nu$ decay. https://doi.org/10.1007/jhep03(2024)137

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