Observation of the K+→π+νν¯ decay and measurement of its branching ratio

The NA62 Collaboration

doi:10.1007/JHEP02(2025)191

Observation of the K+→π+νν¯ decay and measurement of its branching ratio

The NA62 Collaboration

Department of Pharmaceutical Sciences

Research output: Contribution to journal › Article › peer-review

Abstract

A measurement of the K+→π+νν¯ decay by the NA62 experiment at the CERN SPS is presented, using data collected in 2021 and 2022. This dataset was recorded, after modifications to the beamline and detectors, at a higher instantaneous beam intensity with respect to the 2016–2018 data taking. Combining NA62 data collected in 2016–2022, a measurement of BK+→π+νν¯=13.0−3.0+3.3×10−11 is reported. With 51 signal candidates observed and an expected background of 18−2+3 events, BK+→π+νν¯ becomes the smallest branching ratio measured with a signal significance above 5σ.

Original language	English
Article number	191
Journal	Journal of High Energy Physics
Volume	2025
Issue number	2
DOIs	https://doi.org/10.1007/JHEP02(2025)191
Publication status	Published - Feb 2025

Keywords

Branching fraction
Flavour Physics
Other Experiments
Rare Decay

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10.1007/JHEP02(2025)191

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@article{156b6a908a05477b862f210a84dbf875,

title = "Observation of the K+→π+νν¯ decay and measurement of its branching ratio",

abstract = "A measurement of the K+→π+νν¯ decay by the NA62 experiment at the CERN SPS is presented, using data collected in 2021 and 2022. This dataset was recorded, after modifications to the beamline and detectors, at a higher instantaneous beam intensity with respect to the 2016–2018 data taking. Combining NA62 data collected in 2016–2022, a measurement of BK+→π+νν¯=13.0−3.0+3.3×10−11 is reported. With 51 signal candidates observed and an expected background of 18−2+3 events, BK+→π+νν¯ becomes the smallest branching ratio measured with a signal significance above 5σ.",

keywords = "Branching fraction, Flavour Physics, Other Experiments, Rare Decay",

author = "\{The NA62 Collaboration\} and \{Cortina Gil\}, E. and J. Jerhot and N. Lurkin and T. Numao and B. Velghe and Wong, \{V. W.S.\} and D. Bryman and Z. Hives and T. Husek and K. Kampf and M. Kolesar and M. Koval and \{De Martino\}, B. and M. Perrin-Terrin and L. Petit and B. D{\"o}brich and S. Lezki and J. Schubert and Akmete, \{A. T.\} and R. Aliberti and M. Ceoletta and \{Di Lella\}, L. and N. Doble and L. Peruzzo and C. Polivka and S. Schuchmann and H. Wahl and R. Wanke and P. Dalpiaz and R. Negrello and I. Neri and F. Petrucci and M. Soldani and L. Bandiera and N. Canale and \{Cotta Ramusino\}, A. and A. Gianoli and M. Romagnoni and A. Sytov and M. Lenti and \{Lo Chiatto\}, P. and I. Panichi and G. Ruggiero and A. Bizzeti and F. Bucci and A. Antonelli and V. Kozhuharov and G. Lanfranchi and S. Martellotti and R. Arcidiacono",

note = "Publisher Copyright: {\textcopyright} The Author(s) 2025.",

year = "2025",

month = feb,

doi = "10.1007/JHEP02(2025)191",

language = "English",

volume = "2025",

journal = "Journal of High Energy Physics",

issn = "1029-8479",

publisher = "Springer Verlag",

number = "2",

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TY - JOUR

T1 - Observation of the K+→π+νν¯ decay and measurement of its branching ratio

AU - The NA62 Collaboration

AU - Cortina Gil, E.

AU - Jerhot, J.

AU - Lurkin, N.

AU - Numao, T.

AU - Velghe, B.

AU - Wong, V. W.S.

AU - Bryman, D.

AU - Hives, Z.

AU - Husek, T.

AU - Kampf, K.

AU - Kolesar, M.

AU - Koval, M.

AU - De Martino, B.

AU - Perrin-Terrin, M.

AU - Petit, L.

AU - Döbrich, B.

AU - Lezki, S.

AU - Schubert, J.

AU - Akmete, A. T.

AU - Aliberti, R.

AU - Ceoletta, M.

AU - Di Lella, L.

AU - Doble, N.

AU - Peruzzo, L.

AU - Polivka, C.

AU - Schuchmann, S.

AU - Wahl, H.

AU - Wanke, R.

AU - Dalpiaz, P.

AU - Negrello, R.

AU - Neri, I.

AU - Petrucci, F.

AU - Soldani, M.

AU - Bandiera, L.

AU - Canale, N.

AU - Cotta Ramusino, A.

AU - Gianoli, A.

AU - Romagnoni, M.

AU - Sytov, A.

AU - Lenti, M.

AU - Lo Chiatto, P.

AU - Panichi, I.

AU - Ruggiero, G.

AU - Bizzeti, A.

AU - Bucci, F.

AU - Antonelli, A.

AU - Kozhuharov, V.

AU - Lanfranchi, G.

AU - Martellotti, S.

AU - Arcidiacono, R.

PY - 2025/2

Y1 - 2025/2

N2 - A measurement of the K+→π+νν¯ decay by the NA62 experiment at the CERN SPS is presented, using data collected in 2021 and 2022. This dataset was recorded, after modifications to the beamline and detectors, at a higher instantaneous beam intensity with respect to the 2016–2018 data taking. Combining NA62 data collected in 2016–2022, a measurement of BK+→π+νν¯=13.0−3.0+3.3×10−11 is reported. With 51 signal candidates observed and an expected background of 18−2+3 events, BK+→π+νν¯ becomes the smallest branching ratio measured with a signal significance above 5σ.

AB - A measurement of the K+→π+νν¯ decay by the NA62 experiment at the CERN SPS is presented, using data collected in 2021 and 2022. This dataset was recorded, after modifications to the beamline and detectors, at a higher instantaneous beam intensity with respect to the 2016–2018 data taking. Combining NA62 data collected in 2016–2022, a measurement of BK+→π+νν¯=13.0−3.0+3.3×10−11 is reported. With 51 signal candidates observed and an expected background of 18−2+3 events, BK+→π+νν¯ becomes the smallest branching ratio measured with a signal significance above 5σ.

KW - Branching fraction

KW - Flavour Physics

KW - Other Experiments

KW - Rare Decay

UR - https://www.scopus.com/pages/publications/105003027836

U2 - 10.1007/JHEP02(2025)191

DO - 10.1007/JHEP02(2025)191

M3 - Article

SN - 1029-8479

VL - 2025

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

IS - 2

M1 - 191

ER -

Observation of the K+→π+νν¯ decay and measurement of its branching ratio

Abstract

Keywords

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