Measurement of the very rare K<sup>+</sup> → π<sup>+</sup>ν(Equation presented) decay at the NA62 experiment at CERN



Fiorenza, R, Akmete, A, Aliberti, R, Ambrosino, F, Ammendola, R, Angelucci, B, Antonelli, A, Anzivino, G, Arcidiacono, R, Bache, T
et al (show 90 more authors) (2022) Measurement of the very rare K<sup>+</sup> → π<sup>+</sup>ν(Equation presented) decay at the NA62 experiment at CERN. .

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Abstract

The NA62 experiment reports the branching ratio measurement BR(K+ → π+ν(Equation presented)) at 68 % CL, based on the observation of 20 signal candidates with an expected background of 7.0 events from the total data sample collected at the CERN SPS during 2016-2018. This provides evidence for the very rare K+ → π+ν(Equation presented) decay, observed with a significance of 3.4σ. The experiment achieves a single event sensitivity of (0.839 ± 0.054) × 10−11, corresponding to 10.0 events assuming the Standard Model branching ratio of (8.4 ± 1.0) × 10−11. The result represents the most accurate measurement achieved so far of this ultra-rare decay. Future prospects and plans for data taking from 2021 will also be presented.

Item Type: Conference or Workshop Item (Unspecified)
Depositing User: Symplectic Admin
Date Deposited: 11 Oct 2022 13:42
Last Modified: 18 Jan 2023 20:36
Open Access URL: https://pos.sissa.it/402/176/
URI: https://livrepository.liverpool.ac.uk/id/eprint/3165368