Measurement of the KS → πeν branching fraction with the KLOE experiment

Autor: The KLOE-2 collaboration, D. Babusci, M. Berlowski, C. Bloise, F. Bossi, P. Branchini, B. Cao, F. Ceradini, P. Ciambrone, F. Curciarello, E. Czerwiński, G. D’Agostini, R. D’Amico, E. Danè, V. De Leo, E. De Lucia, A. De Santis, P. De Simone, A. Di Cicco, A. Di Domenico, E. Diociaiuti, D. Domenici, A. D’Uffizi, G. Fantini, A. Gajos, S. Gamrat, P. Gauzzi, S. Giovannella, E. Graziani, X. Kang, A. Kupsc, G. Mandaglio, M. Martini, S. Miscetti, P. Moskal, A. Passeri, E. Perez del Rio, M. Schioppa, A. Selce, M. Silarski, F. Sirghi, E. P. Solodov, W. Wiślicki, M. Wolke
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Journal of High Energy Physics, Vol 2023, Iss 2, Pp 1-19 (2023)
Druh dokumentu: article
ISSN: 1029-8479
DOI: 10.1007/JHEP02(2023)098
Popis: Abstract The ratio R $$ \mathcal{R} $$ = Γ(K S → πeν)/Γ(K S → π + π − ) has been measured with a sample of 300 million K S mesons produced in ϕ → K L K S decays recorded by the KLOE experiment at the DAΦNE e + e − collider. K S → πeν events are selected by a boosted decision tree built with kinematic variables and time-of-flight measurements. Data control samples of K L → πeν decays are used to evaluate signal selection efficiencies. With 49647±316 signal events we measure R $$ \mathcal{R} $$ = (1.0421 ± 0.0066stat ± 0.0075syst) × 10 −3. The combination with our previous measurement gives R $$ \mathcal{R} $$ = (1.0338 ± 0.0054stat ± 0.0064syst) × 10 −3. From this value we derive the branching fraction B $$ \mathcal{B} $$ (K S → πeν) = (7.153 ± 0.037stat ± 0.044syst) × 10 −4 and f +(0)|V us | = 0.2170 ± 0.009.
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