The ratio R = gamma(K-S -> pi e nu)/gamma(KS -> pi(+)pi(-)) has beenmeasured with a sample of 300 million KS mesons produced in phi -KLKSdecays recorded by the KLOE experiment at the DA Phi NE e(+)e(-)collider. K-S -> pi e nu events are selected by a boosted decision treebuilt with kinematic variables and time-of-flight measurements. Datacontrol samples of K-L -> pi e nu decays are used to evaluate signalselection efficiencies. With 49647 +/- 316 signal events we measure R =(1.0421 +/- 0.0066(stat) +/- 0.0075(syst)) x 10(-3). The combinationwith our previous measurement gives R = (1.0338 +/- 0.0054(stat) +/-0.0064(syst)) x 10(-3). From this value we derive the branching fractionB(K-S -> pi e nu) = (7.153 +/- 0.037(stat)+/- 0.044(syst)) x 10(-4) andf(+)(0)|V-us| = 0.2170 +/- 0.009.
Measurement of the KS ? pe? branching fraction with the KLOE experiment
Martini M.;
2023-01-01
Abstract
The ratio R = gamma(K-S -> pi e nu)/gamma(KS -> pi(+)pi(-)) has beenmeasured with a sample of 300 million KS mesons produced in phi -KLKSdecays recorded by the KLOE experiment at the DA Phi NE e(+)e(-)collider. K-S -> pi e nu events are selected by a boosted decision treebuilt with kinematic variables and time-of-flight measurements. Datacontrol samples of K-L -> pi e nu decays are used to evaluate signalselection efficiencies. With 49647 +/- 316 signal events we measure R =(1.0421 +/- 0.0066(stat) +/- 0.0075(syst)) x 10(-3). The combinationwith our previous measurement gives R = (1.0338 +/- 0.0054(stat) +/-0.0064(syst)) x 10(-3). From this value we derive the branching fractionB(K-S -> pi e nu) = (7.153 +/- 0.037(stat)+/- 0.044(syst)) x 10(-4) andf(+)(0)|V-us| = 0.2170 +/- 0.009.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
