Search for heavy neutral leptons in π+ decays to positrons

NA62 Collaboration

doi:10.1016/j.physletb.2025.140119

Search for heavy neutral leptons in π+ decays to positrons

NA62 Collaboration

Physics and Astronomy

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

Abstract

A search for heavy neutral lepton (N) production in π⁺→e⁺N in-flight decays using data collected by the NA62 experiment at CERN in 2017–2024 is reported. Upper limits for the extended neutrino mixing matrix element |U_e4|² are established at the level of 10⁻⁸ for heavy neutral leptons with mass in the range 95–126 MeV/c² and lifetime exceeding 50 ns.

Original language	English
Article number	140119
Number of pages	7
Journal	Physics Letters B
Volume	872
Early online date	26 Dec 2025
DOIs	https://doi.org/10.1016/j.physletb.2025.140119
Publication status	Published - Jan 2026

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10.1016/j.physletb.2025.140119Licence: Creative Commons: Attribution (CC BY)

BlochDevauxB2025SearchFinal published version, 2.48 MBLicence: Creative Commons: Attribution (CC BY)

KaonToALP - Search for axion-like particle production in kaon decays at CERN-NA62 experiment
Goudzovski, E. (Principal Investigator)
European Commission
4/05/21 → 11/07/23
Project: EU
H2020_IF_NEWLIGHTSCALAR
Goudzovski, E. (Principal Investigator)
European Commission
3/07/17 → 2/07/19
Project: EU
FP7_ERC_KaonLepton
Lazzeroni, C. (Co-Investigator) & Goudzovski, E. (Principal Investigator)
European Commission, European Commission - Management Costs
1/01/14 → 30/06/19
Project: Research
Ernest Rutherford Fellowship : Dr Antonio Sergi - Development of the NA62 Detector and Search for New Physics with Kaon Decays
Sergi, A. (Principal Investigator)
SCIENCE & TECHNOLOGY FACILITIES COUNCIL
25/03/13 → 24/03/18
Project: Research Councils
Fellowship : Dr Evgueni Goudzovski - New-Physics Discovery with Rare Kaon Decays
Goudzovski, E. (Principal Investigator)
The Royal Society
1/04/12 → 31/03/17
Project: Research Councils
FP7 ERC - UniversaLepto : Test of Lepton Flavour Universality with Kaon Decays
Lazzeroni, C. (Principal Investigator)
European Commission - Management Costs, European Commission
1/09/11 → 31/08/16
Project: Research

Cite this

@article{0d42479fbf734846b13cd0e32fa31a52,

title = "Search for heavy neutral leptons in π+ decays to positrons",

abstract = "A search for heavy neutral lepton (N) production in π+→e+N in-flight decays using data collected by the NA62 experiment at CERN in 2017–2024 is reported. Upper limits for the extended neutrino mixing matrix element |Ue4|2 are established at the level of 10−8 for heavy neutral leptons with mass in the range 95–126 MeV/c2 and lifetime exceeding 50 ns. ",

author = "\{NA62 Collaboration\} and E. Goudzovski and C. Kenworthy and C. Lazzeroni and A. Romano and C. Sam and A. Sergi and A. Tomczak",

year = "2026",

month = jan,

doi = "10.1016/j.physletb.2025.140119",

language = "English",

volume = "872",

journal = "Physics Letters B",

issn = "0370-2693",

publisher = "Elsevier",

}

TY - JOUR

T1 - Search for heavy neutral leptons in π+ decays to positrons

AU - NA62 Collaboration

AU - Goudzovski, E.

AU - Kenworthy, C.

AU - Lazzeroni, C.

AU - Romano, A.

AU - Sam, C.

AU - Sergi, A.

AU - Tomczak, A.

PY - 2026/1

Y1 - 2026/1

N2 - A search for heavy neutral lepton (N) production in π+→e+N in-flight decays using data collected by the NA62 experiment at CERN in 2017–2024 is reported. Upper limits for the extended neutrino mixing matrix element |Ue4|2 are established at the level of 10−8 for heavy neutral leptons with mass in the range 95–126 MeV/c2 and lifetime exceeding 50 ns.

AB - A search for heavy neutral lepton (N) production in π+→e+N in-flight decays using data collected by the NA62 experiment at CERN in 2017–2024 is reported. Upper limits for the extended neutrino mixing matrix element |Ue4|2 are established at the level of 10−8 for heavy neutral leptons with mass in the range 95–126 MeV/c2 and lifetime exceeding 50 ns.

U2 - 10.1016/j.physletb.2025.140119

DO - 10.1016/j.physletb.2025.140119

M3 - Letter

SN - 0370-2693

VL - 872

JO - Physics Letters B

JF - Physics Letters B

M1 - 140119

ER -

Search for heavy neutral leptons in π+ decays to positrons

Abstract

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Projects

KaonToALP - Search for axion-like particle production in kaon decays at CERN-NA62 experiment

H2020_IF_NEWLIGHTSCALAR

FP7_ERC_KaonLepton

Ernest Rutherford Fellowship : Dr Antonio Sergi - Development of the NA62 Detector and Search for New Physics with Kaon Decays

Fellowship : Dr Evgueni Goudzovski - New-Physics Discovery with Rare Kaon Decays

FP7 ERC - UniversaLepto : Test of Lepton Flavour Universality with Kaon Decays

Cite this