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Determination of the $\pi \pi$ scattering lengths from a study of $K^{\pm} \to \pi^{\pm} \pi^{0} \pi^{0}$ decays (2009) |
- Batley, J R,
- Culling, A J,
- Kalmus, G,
- Lazzeroni, C,
- Munday, D J,
- Slater, M W,
- Wotton, S A,
- Arcidiacono, R,
- Bocquet, G,
- Cabibbo, N,
- Ceccucci, A,
- Cundy, D,
- Falaleev, V,
- Fidecaro, Maria,
- Gatignon, L,
- Gonidec, A,
- Kubischta, W,
- 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,
- Calvetti, M,
- Iacopini, E,
- Ruggiero, G,
- Bizzeti, A,
- Lenti, M,
- Veltri, M,
- Behler, M,
- Eppard, K,
- 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, G,
- Imbergamo, E,
- Nappi, A,
- Piccini, M,
- Raggi, M,
- Valdata-Nappi, M,
- Cenci, P,
- Pepé, M,
- Pettrucci, M C,
- Cerri, C,
- Fantechi, R,
- Collazuol, G,
- Di Lella, L,
- Lamanna, G,
- Mannelli, I,
- Michetti, A,
- Costantini, F,
- Doble, N,
- Fiorini, L,
- Giudici, S,
- Pierazzini, G,
- Sozzi, M,
- Venditti, S,
- Bloch-Devaux, B,
- Cheshkov, C,
- Chèze, J B,
- De Beer, M,
- Derré, J,
- Marel, G,
- Mazzucato, E,
- Peyaud, B,
- Vallage, B,
- Holder, M,
- Ziolkowski, M,
- Bifani, S,
- Biino, C,
- Cartiglia, N,
- Marchetto, F,
- Bifani, S,
- Clemencic, M,
- Goy-Lopez, S,
- Dibon, H,
- Jeitler, M,
- Markytan, M,
- Mikulec, I,
- Neuhofer, G,
- Widhalm, L
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Abstract |
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We report the results from a study of the full sample of $~6.031 x 10^{7} K^{\pm} \to \pi^{\pm} \pi^{0} \pi^{0}$ decays recorded by the NA48/2 experiment at the CERN SPS. As first observed in this experiment, the $\pi^{0} \pi^{0}$ invariant mass (M_00) distribution shows a cusp-like anomaly in the region around $M_{00} = 2m_{+}$, where m_{+} is the charged pion mass. This anomaly has been interpreted as an effect due mainly to the final state charge exchange scattering process $\pi^{+}\pi^{-} \to \pi^{0} \pi^{0}$ in $K^{\pm} \to \pi^{\pm} \pi^{+} \pi^{-}$ decay. Fits to the M_{00} distribution using two different theoretical models provide the presently most precise determination of $a_{0}-a_{2}$, the difference between the pi pi S-wave scattering lengths in the isospin I = 0 and I = 2 states. Higher-order pi pi rescattering terms, included in the two models, allow also an independent, though less precise, determination of a_2. |
Publication details |
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