First observation and measurement of the decay K± → π± e+ e- γ

J. R. Batley, A. J. Culling, G. Kalmus, 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, A. Maier, M. PatelA. Peters, S. Balev, P. L. Frabetti, E. Goudzovski, P. Hristov, V. Kekelidze, V. Kozhuharov, L. Litov, D. Madigozhin, E. Marinova, N. Molokanova, I. Polenkevich, Yu 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, C. Handel, 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, Mayda Velasco, M. D. Wood, G. Anzivino, P. Cenci, E. Imbergamo, A. Nappi, 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, 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

*Corresponding author for this work

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

Using the full data set of the NA48/2 experiment, the decay K± → π± e+ e- γ is observed for the first time, selecting 120 candidates with 7.3 ± 1.7 estimated background events. With K± → π± πD0 as normalisation channel, the branching ratio is determined in a model-independent way to be Br (K± → π± e+ e- γ, me e γ > 260  MeV / c2) = (1.19 ± 0.12stat ± 0.04syst) × 10-8. This measured value and the spectrum of the e+ e- γ invariant mass allow a comparison with predictions of chiral perturbation theory.

Original languageEnglish (US)
Pages (from-to)493-499
Number of pages7
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume659
Issue number3
DOIs
StatePublished - Jan 24 2008

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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