Measurement of the decay rate and the parameter αK* of the decay KL → μμγ

V. Fanti*, A. Lai, L. Musa, A. Nappi, M. G. Setzu, R. W. Moore, D. J. Munday, M. A. Parker, S. F. Takach, T. O. White, G. Barr, G. Bocquet, J. Bremer, A. Ceccucci, J. Cogan, D. Cundy, N. Doble, G. Fischer, W. Funk, L. GatignonA. Gianoli, A. Gonidec, P. Grafstrom, W. Kubischta, V. Marzulli, G. Kesseler, J. P. Matheys, A. Norton, S. Palestini, B. Panzer-Steindel, H. Taureg, M. Velasco, O. Vossnack, H. Wahl, V. Kekelidze, I. Kojevnikov, I. Potrebenikov, G. Tatichvili, A. Tkatchev, L. Bertolotto, O. Boyle, B. Hay, N. E. Mc Kay, G. Oakland, H. Parsons, K. J. Peach, C. Talamonti, A. Walker, P. Dalpiaz, J. Duclos, A. Formica, P. L. Frabetti, M. Martini, F. Petrucci, M. Porcu, F. Rossi, M. Savrie, C. Simani, A. Bizzeti, M. Calvetti, M. Lenti, A. Michetti, H. G. Becker, T. Beier, H. Blümer, P. Buchholz, D. Coward, C. Ebersberger, A. Kalter, K. Kleinknecht, U. Koch, L. Köpke, F. Leber, S. Luitz, B. Renk, J. Scheidt, J. Schmidt, V. Schönharting, R. Wilhelm, O. Zeitnitz, J. C. Chollet, S. Crépé, L. Fayard, J. Ocariz, G. Unal, G. Anzivino, P. Cenci, P. Lubrano, M. Pepe, P. Calafiura, R. Carosi, R. Casali, C. Cerri, F. Costantini, R. Fantechi, S. Giudici, B. Gorini, I. Mannelli, G. Pierazzini, M. Sozzi, J. B. Cheze, M. De Beer, P. Debu, P. Hristov, E. Mazzucato, B. Peyaud, S. Schanne, O. Steinkamp, R. Turlay, B. Vallage, I. Augustin, M. Bender, M. Holder, I. Schwarze, M. Ziolkowski, R. Arcidiacono, C. Biino, G. Govi, P. Maas, F. Marchetto, E. Menichetti, H. Dibon, M. Jeitler, M. Markytan, I. Mikulec, G. Neuhofer, M. Pernicka, A. Taurok

*Corresponding author for this work

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9 Scopus citations


The rate of the decay of the neutral K meson into KL0 → μμγ has been measured with the NA48 detector at the CERN SPS. A total of 59 events has been observed with an estimated background of 14 events. The overall Kaon flux was determined to be 1.2 × 109. This observation corresponds to a branching ratio of (3.4 ± 0.6stat ± 0.4sys) × 10-7. Using this branching ratio the parameter αK* describing the relative strength of the two contributing amplitudes to this decay, through intermediate pseudoscalar or vector-like mesons, was measured to be αK*= -0.04-0.21+0.24.

Original languageEnglish (US)
Pages (from-to)653-657
Number of pages5
JournalZeitschrift fur Physik C-Particles and Fields
Issue number4
StatePublished - Dec 1997

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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