The new $K_S \rightarrow πe ν$ branching fraction measurement at KLOE

Fuente: arXiv
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Main Author: Passeri, A.
Format: Preprint
Published: 2024
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author Passeri, A.
author_facet Passeri, A.
contents A new measurement of the branching fraction for the decay $K_S \rightarrow πe ν$ is presented, based on a sample of 300 million $K_S$ mesons recorded by the KLOE experiment at the DA$Φ$NE $e^+e^-$ collider. A two-step signal selection strategy is used, exploiting first kinematic variables and then time-of-flight measurements. Data control samples of $K_S \rightarrow πe ν$ decays are used to evaluate signal selection efficiencies. Normalizing the selected sample to the number of $K_S \rightarrow π^+ π^-$ decay events the result for the branching fraction is $B(K_S \rightarrow πe ν)=(7.211 \pm 0.046 \pm 0.052)\times 10^-4$. The combination with our previous measurement gives $B(K_S \rightarrow πe ν)=(7.153 \pm 0.037 \pm 0.043)\times 10^-4 =(7.153 \pm 0.057)\times 10^-4$. From this value we derive $f^+(0)|Vus|=0.2170 \pm 0.0009$.
format Preprint
id arxiv_https___arxiv_org_abs_2404_01826
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The new $K_S \rightarrow πe ν$ branching fraction measurement at KLOE
Passeri, A.
High Energy Physics - Experiment
A new measurement of the branching fraction for the decay $K_S \rightarrow πe ν$ is presented, based on a sample of 300 million $K_S$ mesons recorded by the KLOE experiment at the DA$Φ$NE $e^+e^-$ collider. A two-step signal selection strategy is used, exploiting first kinematic variables and then time-of-flight measurements. Data control samples of $K_S \rightarrow πe ν$ decays are used to evaluate signal selection efficiencies. Normalizing the selected sample to the number of $K_S \rightarrow π^+ π^-$ decay events the result for the branching fraction is $B(K_S \rightarrow πe ν)=(7.211 \pm 0.046 \pm 0.052)\times 10^-4$. The combination with our previous measurement gives $B(K_S \rightarrow πe ν)=(7.153 \pm 0.037 \pm 0.043)\times 10^-4 =(7.153 \pm 0.057)\times 10^-4$. From this value we derive $f^+(0)|Vus|=0.2170 \pm 0.0009$.
title The new $K_S \rightarrow πe ν$ branching fraction measurement at KLOE
topic High Energy Physics - Experiment
url https://arxiv.org/abs/2404.01826