Measurements of charged kaon semileptonic decay branching fractions K ±→π0μ±ν and K ±→π0e±ν and their ratio

Batley, J. R.; Lazzeroni, C.; Munday, D. J.; Slater, M. W.; Wotton, S. A.; Arcidiacono, R.; Bocquet, G.; Cabibbo, N.; Ceccucci, A.; Cundy, D.; Falaleev, V.; Fidecaro, M.; Gatignon, L.; Gonidec, A.; Kubischta, W.; Norton, A.; Patel, M.; Peters, A.; Balev, S.; Frabetti, P. L.; Goudzovski, E.; Hristov, P.; Kozhuharov, V.; Litov, L.; Madigozhin, D.; Marinova, E.; Molokanova, N.; Polenkevich, I.; Potrebenikov, Y.; 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.; Savriã©, M.; Scarpa, M.; Wahl, H.; Bizzeti, Andrea; Calvetti, M.; Celeghini, E.; Iacopini, E.; Lenti, M.; Martelli, F.; Ruggiero, G.; 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.; Cenci, P.; Imbergamo, E.; Pepe, M.; Petrucci, M. C.; Piccini, M.; Raggi, M.; Valdata Nappi, M.; Cerri, C.; Collazuol, G.; Costantini, F.; Dilella, L.; Doble, N.; Fantechi, R.; Fiorini, L.; Giudici, S.; Lamanna, G.; Mannelli, I.; Michetti, A.; Pierazzini, G.; Sozzi, M.; Bloch Devaux, B.; Cheshkov, C.; Chã¨ze, J. B.; De Beer, M.; Derrã©, J.; Marel, G.; Mazzucato, E.; Peyaud, B.; Vallage, B.; Holder, M.; Maier, A.; Ziolkowski, M.; Bifani, S.; Biino, C.; Cartiglia, N.; Clemencic, M.; Goy Lopez, S.; Marchetto, F.; Dibon, H.; Jeitler, M.; Markytan, M.; Mikulec, I.; Neuhofer, G.; Widhalm, L.

doi:10.1140/epjc/s10052-007-0253-3

Measured ratios of decay rates for R(Ke3/K2π) , R(Kμ3/K2π) and R(Kμ3/Ke3) are presented. These measurements are based on K ± decays collected in a dedicated run in 2003 by the NA48/2 experiment at CERN. The results obtained are R(Ke3/K2π) = 0.2496 ± 0.0009(stat) ± 0.0004(syst) and R(Kμ3/K2π) = 0.1637 ± 0.0006(stat) ± 0.0003(syst). Using the PDG average for the K ± → π ± π 0 normalisation mode, both values are found to be larger than the current values given by the particle data book and lead to a larger magnitude of the |Vus| CKM element than previously accepted. When combined with the latest particle data book value of |Vud|, the result is in agreement with unitarity of the CKM matrix. In addition, a new measured value of R(Kμ3/Ke3) = 0.656 ± 0.003(stat) ± 0.001(syst) is compared to the semi-empirical predictions based on the latest form factor measurements.

Measurements of charged kaon semileptonic decay branching fractions K ±→π0μ±ν and K ±→π0e±ν and their ratio / J. R., B., C., L., D. J., M., M. W., S., S. A., W., R., A., G., B., N., C., A., C., D., C., V., F., M., F., L., G., A., G., W., K., A., N., M., P., A., P., S., B., P. L., F., et al.. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - STAMPA. - 50:(2007), pp. 329-340. [10.1140/epjc/s10052-007-0253-3]