Study of the branching ratio and charge asymmetry for the decay KS→πeν with the KLOE detector

Autor: Alessandra Doria, S. Miscetti, Ludovico Pontecorvo, E. Santovetti, T. Spadaro, G. De Zorzi, F. Ambrosino, G. Saracino, S. Chi, S. Conetti, R. Caloi, Stefano Veneziano, M. Moulson, Enrico Pasqualucci, G. Bencivenni, Massimo Antonelli, A. De Santis, G. Xu, Margherita Primavera, Filippo Ceradini, W. Kluge, S. Di Falco, G. Felici, F. Bossi, M. Incagli, B. Di Micco, M. Testa, D. Leone, W. Mei, F. Perfetto, Fabrizio Scuri, S. Fiore, C. Forti, B. Valeriani, Paolo Ciambrone, Juliet Lee-Franzini, Paolo Santangelo, Pierluigi Campana, E. De Lucia, S. Müller, S. Bertolucci, E. Graziani, G. Chiefari, S. Dell'Agnello, F. Murtas, S. Meola, R. Versaci, Igor Sfiligoi, M. Napolitano, C. Di Donato, Claudio Gatti, S. Giovannella, C. Bloise, P. De Simone, P. Beltrame, Andrea Ferrari, C. Bacci, Cesare Bini, A. Di Domenico, P. Massarotti, Barbara Sciascia, Andrea Ventura, M. Martini, G. Capon, V. V. Kulikov, A. Passeri, P. Franzini, F. Nguyen, P. Branchini, M. Dreucci, Luca Tortora, Francesco Lacava, G. Lanfranchi, P. Gauzzi, G. Finocchiaro, P. Valente, D. Bowring, T. Capussela, G. Venanzoni, A. Antonelli, Vincenzo Patera, M. L. Ferrer, A. Denig, A. Sciubba, V. Bocci, M. Palutan, Edoardo Gorini
Rok vydání: 2006
Předmět:
Zdroj: Physics Letters B. 636:173-182
ISSN: 0370-2693
DOI: 10.1016/j.physletb.2006.03.047
Popis: Among some 400 million K S K L pairs produced in e + e − annihilations at DAΦNE, ∼6500 each of K S → π + e − ν ¯ and K S → π − e + ν decays have been observed with the KLOE detector. From these, the ratio Γ ( K S → π e ν ) / Γ ( K S → π + π − ) = ( 10.19 ± 0.13 ) × 10 −4 is obtained, improving the accuracy on BR ( K S → π e ν ) by a factor of four and providing the most precise test of the Δ S = Δ Q rule. From the partial width Γ ( K S → π e ν ) , a value for f + K 0 ( 0 ) × V u s is obtained that is in agreement with unitarity of the quark-mixing matrix. The lepton charge asymmetry A S = ( 1.5 ± 9.6 stat ± 2.9 syst ) × 10 −3 is compatible with the requirements of CPT invariance. The form-factor slope agrees with recent results from semileptonic K L and K + decays. These are the first measurements of the charge asymmetry and form-factor slope for semileptonic K S decays.
Databáze: OpenAIRE
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