Precise measurements of the KS→γγ and KL→γγ decay rates

• Published in: Physics letters. B 2003-01, Vol.551 (1-2), p.7-15
• Main Authors: Lai, A, Marras, D, Batley, J.R, Kalmus, G.E, Munday, D.J, Olaiya, E, White, T.O, Wotton, S.A, Arcidiacono, R, Bocquet, G, Cuhadar-Dönszelmann, T, Cundy, D, Doble, N, Falaleev, V, Gatignon, L, Gorini, B, Grafström, P, Kubischta, W, Lacourt, A, Mikulec, I, Tatishvili, G, Wahl, H, Cheshkov, C, Hristov, P, Kekelidze, V, Madigojine, D, Molokanova, N, Zinchenko, A, Martin, V, Rubin, P, Sacco, R, Walker, A, Contalbrigo, M, Duclos, J, Frabetti, P.L, Martini, M, Petrucci, F, Savrié, M, Bizzeti, A, Calvetti, M, Collazuol, G, Graziani, G, Iacopini, E, Lenti, M, Veltri, M, Eppard, M, Hirstius, A, Holtz, K, Kleinknecht, K, Köpke, L, Marouelli, P, Mestvirishvili, I, Pellmann, I, Peters, A, Schmidt, S.A, Schönharting, V, Schué, Y, Wanke, R, Winhart, A, Wittgen, M, Chollet, J.C, Iconomidou-Fayard, L, Wingerter-Seez, I, Cenci, P, Imbergamo, E, Lubrano, P, Mestvirishvili, A, Nappi, A, Piccini, M, Cerri, C, Cirilli, M, Costantini, F, Fantechi, R, Fiorini, L, Giudici, S, Pierazzini, G, Sozzi, M, Cheze, J.B, De Beer, M, Derue, F, Formica, A, Granier de Cassagnac, R, Marel, G, Peyaud, B, Turlay, R, Vallage, B, Maier, A, Ziolkowski, M, Cartiglia, N, Marchetto, F, Menichetti, E, Rondio, E, Szleper, M, Dibon, H, Jeitler, M, Markytan, M, Neuhofer, G, Pernicka, M, Taurok, A, Widhalm, L
• Format: Article
• Language: English
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/S0370-2693(02)02955-6

The KS→γγ decay rate has been measured with the NA48 detector using a high intensity short neutral beam from the CERN SPS. The measured branching ratio BR(KS→γγ)=(2.78±0.06stat±0.04syst)×10−6, obtained from 7461±172 KS→γγ events, is significantly higher than the O(p4) prediction of chiral perturbation theory. Using a KL beam the ratio Γ(KL→γγ)Γ(KL→π0π0π0)=(2.81±0.01stat±0.02syst)×10−3 has been measured.