Observation of the decay KS → π+π-e+e-

A. Lai, D. Marras, L. Musa, A. Bevan, R. S. Dosanjh, T. J. Gershon, B. Hay, G. E. Kalmus, D. J. Munday, M. D. Needham, E. Olaiya, M. A. Parker, T. O. White, S. A. Wotton, G. Barr, H. Blümer, G. Bocquet, A. Ceccucci, D. Cundy, G. D'AgostiniN. Doble, V. Falaleev, L. Gatignon, A. Gonidec, G. Govi, P. Grafström, W. Kubischta, A. Lacourt, A. Norton, S. Palestini, B. Panzer-Steindel, B. Peyaud, H. Taureg, M. Velasco, H. Wahl, C. Cheshkov, P. Hristov, V. Kekelidze, D. Madigojine, A. Mestvirishvili, N. Molokanova, Y. Potrebenikov, G. Tatishvili, A. Tkatchev, A. Zinchenko, I. Knowles, V. Martin, H. Parsons, R. Sacco, C. Lazzeroni, A. Walker, M. Contalbrigo, P. Dalpiaz, J. Duclos, P. L. Frabetti, A. Gianoli, M. Martini, F. Petrucci, M. Savrié, A. Bizzeti, M. Calvetti, G. Collazuol, G. Graziani, E. Iacopini, M. Lenti, H. G. Becker, M. Eppard, H. Fox, K. Holtz, A. Kalter, K. Kleinknecht, U. Koch, L. Köpke, I. Pellmann, A. Peters, B. Renk, S. A. Schmidt, V. Schönharting, Y. Schué, A. Winhart, M. Wittgen, J. C. Chollet, S. Crépé, L. Fayard, L. Iconomidou-Fayard, J. Ocariz, G. Unal, I. Wingerter-Seez, G. Anzivino, P. Cenci, E. Imbergamo, P. Lubrano, A. Nappi, M. Pepe, M. Piccini, R. Carosi, R. Casali, C. Cerri, M. Cirilli, F. Costantini, R. Fantechi, S. Giudici, B. Gorini, I. Mannelli, G. Pierazzini, M. Sozzi, J. B. Cheze, J. Cogan, M. de Beer, P. Debu, A. Formica, R. Granier de Cassagnac, E. Mazzucato*, R. Turlay, B. Vallage, I. Augustin, M. Bender, M. Holder, M. Ziolkowski, R. Arcidiacono, C. Biino, F. Marchetto, E. Menichetti, N. Pastrone, J. Nassalski, E. Rondio, M. Szleper, W. Wislicki, S. Wronka, H. Dibon, G. Fischer, M. Jeitler, M. Markytan, I. Mikulec, G. Neuhofer, M. Pernicka, A. Taurok

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


We present the first observation of the decay KS → π+π-e+e- based upon the data collected in 1998 by the NA48 experiment at CERN. We have identified a clean sample of 56 events with negligible background contamination. Using KL → π+π-πD/0 decays as normalization sample, the branching ratio is measured to be BR(KS → π+π-e+e-) = [4,5 ± 0.7 (stat) ± 0.4(syst)] × 10-5. This result is in good agreement with the theoretical expectations from the mechanism of inner bremsstrahlung.

Original languageEnglish (US)
Pages (from-to)137-144
Number of pages8
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Issue number3-4
StatePublished - Dec 28 2000

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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