Precision measurement of the ratio BR(K-S -> pi(+)pi(-)e(+)e(-))/BR(K-L -> pi(+)pi(-)pi(0)(D))

J. R. Batley, G. E. Kalmus, C. Lazzeroni, D. J. Munday, M. Patel, M. W. Slater, S. A. Wotton, R. Arcidiacono, G. Bocquet, A. Ceccucci, D. Cundy, N. Doble, V. Falaleev, L. Gatignon, A. Gonidec, R. Grafstroem, W. Kubischta, F. Marchetto, I. Mikulec, A. NortonB. Panzer-Steindel, P. Rubin, H. Wahl, E. Goudzovski, P. Hristov, V. Kekelidze, V. Kozhuharov, L. Litov, D. Madigozhin, N. Molokanova, Yu. Potrebenikov, S. Stoynev, A. Zinchenko, E. Monnier, E. C. Swallow, R. Winston, R. Sacco, A. Walker, W. Baldini, P. Dalpiaz, P. L. Frabetti, A. Gianoli, M. Martini, F. Petrucci, M. Savrie, M. Scarpa, M. Calvetti, G. Collazuol, E. Iacopini, G. Ruggiero, A. Bizzeti, M. Lenti, M. Veltri, M. Behler, K. Eppard, M. Eppard, A. Hirstius, K. Kleinknecht, U. Koch, P. Marouelli, L. Masetti, U. Moosbrugger, C. Morales Morales, A. Peters, R. Wanke, A. Winhart, A. Dabrowski, T. Fonseca Martin, M. Szleper, M. Velasco, G. Anzivino, E. Imbergamo, G. Lamanna, P. Lubrano, A. Michetti, A. Nappi, M. Piccini, M. Valdata-Nappi, P. Cenci, M. Pepe, M. C. Petrucci, C. Cerri, R. Fantechi, I. Mannelli, F. Costantini, L. Fiorini, S. Giudici, G. Pierazzini, M. Sozzi, C. Cheshkov, J. B. Cheze, M. De Beer, P. Debu, G. Gouge, G. Marel, E. Mazzucato, B. Peyaud, B. Vallage, M. Holder, A. Maier, M. Ziolkowski, C. Biino, N. Cartiglia, M. Clemencic, S. Goy Lopez, E. Menichetti, N. Pastrone, W. Wislicki, H. Dibon, M. Jeitler, M. Markytan, G. Neuhofer, L. Widhalm

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Abstract / Description of output

The K-S -> pi(+)pi(-)e(+)e(-) decay mode was investigated using the data collected in 2002 by the NA48/1 Collaboration. With about 23 k K-S -> pi(+)pi(-)e(+)e(-) events and 59 k K-L -> pi(+)pi(-)pi(0)(D) normalization decays, the K-S -> pi(+)pi(-)e(+)e(-) branching ratio relative to the K-L -> pi(+)pi(-)pi(0)(D) one was determined to be BR(K-S -> pi(+)pi(-)e(+)e(-))/BR(K-L -> pi(+)pi(-)pi(0)(D)) = (3.28 +/- 0.06(stat) +/- 0.04(syst)) x 10(-2). This result was used to set the upper limit vertical bar g(E1)/g(BR)vertical bar < 3.0 at 90% CL on the presence, in the decay amplitude, of an E1 direct emission (g(E1)) term relative to the dominant inner bremsstrahlung (g(BR)) term. The CP-violating asymmetry A(phi) in the sin phi cos phi distribution of K-S -> pi(+)pi(-)e(+)e(-) events, where phi is the angle between the pi(+)pi(-) and the e(+)e(-) decay planes in the kaon centre of mass, was found to be A(phi) = (-0.4 +/- 0.8)%, consistent with zero. These results are in good agreement with a description of the K-S -> pi(+)pi(-)e(+)e(-) decay amplitude dominated by the CF-even inner bremsstrahlung process. (C) 2010 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)301-309
Number of pages9
JournalPhysics Letters B
Issue number4-5
Publication statusPublished - 3 Jan 2011


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