Measurement of the ratio Γ (KL → π+ π-) / Γ (KL → π± e ν) and extraction of the CP violation parameter | η+ - |

A. Lai, D. Marras, A. Bevan, R. S. Dosanjh, T. J. Gershon, B. Hay, G. E. Kalmus, C. Lazzeroni, D. J. Munday, E. Olaiya, M. A. Parker, T. O. White, S. A. Wotton, G. Barr, G. Bocquet, A. Ceccucci, T. Cuhadar-Dönszelmann, D. Cundy, G. D'Agostini, N. DobleV. Falaleev, L. Gatignon, A. Gonidec, B. Gorini, G. Govi, P. Grafström, W. Kubischta, A. Lacourt, A. Norton, S. Palestini, B. Panzer-Steindel, H. Taureg, M. Velasco, H. Wahl, C. Cheshkov, A. Gaponenko, P. Hristov, V. Kekelidze, L. Litov, D. Madigozhin, N. Molokanova, Yu Potrebenikov, S. Stoynev, G. Tatishvili, A. Tkatchev, A. Zinchenko, I. Knowles, V. Martin, R. Sacco, 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, F. Martelli, M. Veltri, H. G. Becker, K. Eppard, M. Eppard, H. Fox, A. Kalter, K. Kleinknecht, U. Koch, L. Köpke, P. Lopes da Silva, P. Marouelli, I. Pellmann, A. Peters, B. Renk, S. A. Schmidt, V. Schönharting, Y. Schué, R. Wanke, A. Winhart*, M. Wittgen, J. C. Chollet, L. Fayard, L. Iconomidou-Fayard, J. Ocariz, G. Unal, I. Wingerter-Seez, G. Anzivino, P. Cenci, E. Imbergamo, P. Lubrano, A. Mestvirishvili, A. Nappi, M. Pepe, M. Piccini, L. Bertanza, R. Carosi, C. Cerri, M. Cirilli, F. Costantini, R. Fantechi, S. Giudici, I. Mannelli, G. Pierazzini, M. Sozzi, J. B. Cheze, J. Cogan, M. De Beer, P. Debu, A. Formica, R. Granier de Cassagnac, E. Mazzucato, B. Peyaud, R. Turlay, B. Vallage, M. Holder, A. Maier, M. Ziolkowski, R. Arcidiacono, C. Biino, N. Cartiglia, R. Guida, 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, L. Widhalm

*Corresponding author for this work

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Abstract

We present a measurement of the ratio of the decay rates Γ (KL → π+ π-) / Γ (KL → π± e ν), denoted as ΓK 2 π / ΓK e 3. The analysis is based on data taken during a dedicated run in 1999 by the NA48 experiment at the CERN SPS. Using a sample of 47 000 K2 π and five million Ke 3 decays, we find ΓK 2 π / ΓK e 3 = (4.835 ± 0.022stat . ± 0.016syst .) × 10-3. From this we derive the branching ratio of the CP violating decay KL → π+ π- and the CP violation parameter | η+ - |. Excluding the CP conserving direct photon emission component KL → π+ π- γ, we obtain the results BR (KL → π+ π-) = (1.941 ± 0.019) × 10-3 and | η+ - | = (2.223 ± 0.012) × 10-3.

Original languageEnglish (US)
Pages (from-to)26-35
Number of pages10
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume645
Issue number1
DOIs
StatePublished - Feb 1 2007

Keywords

  • CP violation
  • Kaon decays

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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