Author:
,Babusci D.,Berlowski M.,Bloise C.,Bossi F.,Branchini P.,Cao B.,Ceradini F.,Ciambrone P.,Curciarello F.,Czerwiński E.,D’Agostini G.,D’Amico R.,Danè E.,De Leo V.,De Lucia E.,De Santis A.,De Simone P.,Di Cicco A.,Di Domenico A.,Diociaiuti E.,Domenici D.,D’Uffizi A.,Fantini G.,Gajos A.,Gamrat S.,Gauzzi P.,Giovannella S.,Graziani E.,Kang X.,Kupsc A.,Mandaglio G.,Martini M.,Miscetti S.,Moskal P.,Passeri A.,Perez del Rio E.,Schioppa M.,Selce A.,Silarski M.,Sirghi F.,Solodov E. P.,Wiślicki W.,Wolke M.
Abstract
Abstract
The ratio $$ \mathcal{R} $$
R
= Γ(KS→ πeν)/Γ(KS→ π+π−) has been measured with a sample of 300 million KS mesons produced in ϕ → KLKS decays recorded by the KLOE experiment at the DAΦNE e+e− collider. KS→ πeν events are selected by a boosted decision tree built with kinematic variables and time-of-flight measurements. Data control samples of KL→ πeν decays are used to evaluate signal selection efficiencies. With 49647±316 signal events we measure $$ \mathcal{R} $$
R
= (1.0421 ± 0.0066stat± 0.0075syst) × 10−3. The combination with our previous measurement gives $$ \mathcal{R} $$
R
= (1.0338 ± 0.0054stat± 0.0064syst) × 10−3. From this value we derive the branching fraction $$ \mathcal{B} $$
B
(KS→ πeν) = (7.153 ± 0.037stat± 0.044syst) × 10−4 and f+(0)|Vus| = 0.2170 ± 0.009.
Publisher
Springer Science and Business Media LLC
Subject
Nuclear and High Energy Physics
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