Based on a sample of 300 million KS mesons produced in ϕ→KLKS decays recorded by the KLOE experiment at the DAΦNE e+e− collider we have measured the branching fraction for the decay KS→πμν. The KS mesons are identified by the interaction of KL mesons in the detector. The KS→πμν decays are selected by a boosted decision tree built with kinematic variables and by a time-of-flight measurement. Signal efficiencies are evaluated with data control samples of KL→πμν decays. A fit to the reconstructed muon mass distribution finds 7223±180 signal events. Normalising to the KS→π+π− decay events the result for the branching fraction is B(KS→πμν)=(4.56±0.11stat±0.17syst)×10−4. It is the first measurement of this decay mode and the result allows an independent determination of |Vus| and a test of the lepton-flavour universality.

Babusci, D., Berlowski, M., Bloise, C., Bossi, F., Branchini, P., Budano, A., et al. (2020). Measurement of the branching fraction for the decay KS → πμν with the KLOE detector. PHYSICS LETTERS. SECTION B, 804, 135378 [10.1016/j.physletb.2020.135378].

Measurement of the branching fraction for the decay KS → πμν with the KLOE detector

Ceradini F.;Di Cicco A.;Selce A.
;
2020

Abstract

Based on a sample of 300 million KS mesons produced in ϕ→KLKS decays recorded by the KLOE experiment at the DAΦNE e+e− collider we have measured the branching fraction for the decay KS→πμν. The KS mesons are identified by the interaction of KL mesons in the detector. The KS→πμν decays are selected by a boosted decision tree built with kinematic variables and by a time-of-flight measurement. Signal efficiencies are evaluated with data control samples of KL→πμν decays. A fit to the reconstructed muon mass distribution finds 7223±180 signal events. Normalising to the KS→π+π− decay events the result for the branching fraction is B(KS→πμν)=(4.56±0.11stat±0.17syst)×10−4. It is the first measurement of this decay mode and the result allows an independent determination of |Vus| and a test of the lepton-flavour universality.
Babusci, D., Berlowski, M., Bloise, C., Bossi, F., Branchini, P., Budano, A., et al. (2020). Measurement of the branching fraction for the decay KS → πμν with the KLOE detector. PHYSICS LETTERS. SECTION B, 804, 135378 [10.1016/j.physletb.2020.135378].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/374816
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