Detailed study of the K± → π 0π0e±ν (Ke400) decay properties

J. R. Batley, 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. Patel, A. PetersS. Balev, P. L. Frabetti, E. Gersabeck, E. Goudzovski, P. Hristov, V. Kekelidze, V. Kozhuharov, L. Litov, D. Madigozhin, 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. Lenti, M. Veltri, M. Calvetti, E. Celeghini, E. Iacopini, G. Ruggiero, M. Behler, K. Eppard, M. Gersabeck, 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, 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. DiLella, G. Lamanna, I. Mannelli, A. Michetti, F. Costantini, N. Doble, L. Fiorini, S. Giudici, G. Pierazzini, M. Sozzi, S. Venditti, 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, C. Biino, N. Cartiglia, F. Marchetto, S. Bifani, M. Clemencic, S. Goy Lopez, H. Dibon, M. Jeitler, M. Markytan, I. Mikulec, G. Neuhofer, L. Widhalm

*Corresponding author for this work

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2 Scopus citations


A sample of 65210 K± → π0π0e±ν (Ke400) decay candidates with 1% background contamination has been collected in 2003-2004 by the NA48/2 collaboration at the CERN SPS. A study of the differential rate provides the first measurement of the hadronic form factor variation in the plane (Mππ2, M2) and brings evidence for a cusp-like structure in the distribution of the squared π0π0 invariant mass around (Formula Presented). Exploiting a model independent description of this form factor, the branching ratio, inclusive of radiative decays, is obtained using the K± → π0π0π± decay mode as normalization. It is measured to be BR(Ke400) = (2.552 ± 0.010stat ± 0.010syst ± 0.032ext) × 10−5, which improves the current world average precision by an order of magnitude while the 1.4% relative precision is dominated by the external uncertainty from the normalization mode. A comparison with the properties of the corresponding mode involving a π+π pair (Ke4+ −) is also presented.

Original languageEnglish (US)
Article number159
JournalJournal of High Energy Physics
Issue number8
StatePublished - Jan 1 2014


  • Branching fraction
  • Fixed target experiments
  • Flavor physics
  • Rare decay

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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