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First Observation and Measurement of the Decay K$^{+-}$ $\to\pi^{+-}e^{+}e^{-}\gamma$ (2007) |
- Batley, J R,
- Culling, A J,
- Kalmus, George Ernest,
- Lazzeroni, C,
- Munday, D J,
- Slater, M W,
- Wotton, S A,
- Arcidiacono, R,
- Bocquet, G,
- Cabibbo, Nicola,
- Ceccucci, A,
- Cundy, Donald C,
- Falaleev, V,
- Fidecaro, Maria,
- Gatignon, L,
- Gonidec, A,
- Kubischta, Werner,
- Norton, A,
- Maier, A,
- Patel, M,
- Peters, A,
- Balev, S,
- Frabetti, P L,
- Goudzovski, E,
- Khristov, P Z,
- Kekelidze, V,
- Kozhuharov, V,
- Litov, L,
- Madigozhin, D T,
- Marinova, E,
- Molokanova, N,
- Polenkevich, I,
- Potrebenikov, Yu,
- Stoynev, S,
- Zinchenko, A,
- Monnier, E,
- Swallow, E,
- Winston, R,
- Rubin, P,
- Walker, A,
- Baldini, W,
- Cotta-Ramusino, A,
- Dalpiaz, P,
- Damiani, C,
- Fiorini, M,
- Gianoli, A,
- Martini, M,
- Petrucci, F,
- Savrié, M,
- Scarpa, M,
- Wahl, H,
- Bizzeti, A,
- Calvetti, M,
- Celeghini, E,
- Iacopini, E,
- Lenti, M,
- Martelli, F,
- Ruggiero, G,
- Veltri, M,
- Behler, M,
- Eppard, K,
- Handel, C,
- Kleinknecht, K,
- Marouelli, P,
- Masetti, L,
- Moosbrugger, U,
- Morales-Morales, C,
- Renk, B,
- Wache, M,
- Wanke, R,
- Winhart, A,
- Coward, D,
- Dabrowski, A,
- Fonseca-Martin, T,
- Shieh, M,
- Szleper, M,
- Velasco, M,
- Wood, M D,
- Anzivino, Giuseppina,
- Cenci, P,
- Imbergamo, E,
- Nappi, A,
- Pepé, M,
- Petrucci, M C,
- Piccini, M,
- Raggi, M,
- Valdata-Nappi, M,
- Cerri, C,
- Collazuol, G,
- Costantini, F,
- Di Lella, L,
- Doble, N,
- Fantechi, R,
- Fiorini, L,
- Giudici, S,
- Lamanna, G,
- Mannelli, I,
- Michetti, A,
- Pierazzini, G,
- Sozzi, M,
- Bloch-Devaux, B,
- Cheshkov, C,
- Chèze, J B,
- De Beer, M,
- Derré, J,
- Marel, Gérard,
- Mazzucato, E,
- Peyaud, B,
- Vallage, B,
- Holder, M,
- Ziolkowski, M,
- Bifani, S,
- Biino, C,
- Cartiglia, N,
- Clemencic, M,
- Goy-Lopez, S,
- Marchetto, F,
- Dibon, Heinz,
- Jeitler, Manfred,
- Markytan, Manfred,
- Mikulec, I,
- Neuhofer, G,
- Widhalm, L
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Abstract |
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Using the full data set of the NA48/2 experiment, the decay K+- -> pi+- e+ e- gamma is observed for the first time, selecting 120 candidates with 7.3 +- 1.7 estimated background events. With K+- -> pi+- pi0D as normalisation channel, the branching ratio is determined in a model-independent way to be Br(K+- -> pi+- e+ e- gamma, m_eegamma > 260 MeV/c^2) = (1.19 +- 0.12_stat +- 0.04_syst) x 10^-8. This measured value and the spectrum of the e+ e- gamma invariant mass allow a comparison with predictions of Chiral Perturbation Theory. |
Publication details |
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