Search for π 0 decays to invisible particles

The NA62 Collaboration

doi:10.1007/JHEP02(2021)201

Search for π ⁰ decays to invisible particles

The NA62 Collaboration

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

Abstract

The NA62 experiment at the CERN SPS reports a study of a sample of 4 × 10⁹ tagged π⁰ mesons from K⁺ → π⁺π⁰(γ), searching for the decay of the π⁰ to invisible particles. No signal is observed in excess of the expected background fluctuations. An upper limit of 4.4 × 10⁻⁹ is set on the branching ratio at 90% confidence level, improving on previous results by a factor of 60. This result can also be interpreted as a model- independent upper limit on the branching ratio for the decay K⁺ → π⁺X, where X is a particle escaping detection with mass in the range 0.110–0.155 GeV/c² and rest lifetime greater than 100 ps. Model-dependent upper limits are obtained assuming X to be an axion-like particle with dominant fermion couplings or a dark scalar mixing with the Standard Model Higgs boson.

Original language	English
Article number	201
Journal	Journal of High Energy Physics
Volume	2021
Issue number	2
DOIs	https://doi.org/10.1007/JHEP02(2021)201
Publication status	Published - 1 Feb 2021

Keywords

Beyond Standard Model
Exotics
Fixed target experiments
Rare decay

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10.1007/JHEP02(2021)201

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title = "Search for π 0 decays to invisible particles",

abstract = "The NA62 experiment at the CERN SPS reports a study of a sample of 4 × 109 tagged π0 mesons from K+ → π+π0(γ), searching for the decay of the π0 to invisible particles. No signal is observed in excess of the expected background fluctuations. An upper limit of 4.4 × 10−9 is set on the branching ratio at 90\% confidence level, improving on previous results by a factor of 60. This result can also be interpreted as a model- independent upper limit on the branching ratio for the decay K+ → π+X, where X is a particle escaping detection with mass in the range 0.110–0.155 GeV/c2 and rest lifetime greater than 100 ps. Model-dependent upper limits are obtained assuming X to be an axion-like particle with dominant fermion couplings or a dark scalar mixing with the Standard Model Higgs boson.",

keywords = "Beyond Standard Model, Exotics, Fixed target experiments, Rare decay",

author = "\{The NA62 Collaboration\} and \{Cortina Gil\}, E. and A. Kleimenova and E. Minucci and S. Padolski and P. Petrov and A. Shaikhiev and R. Volpe and T. Numao and B. Velghe and D. Bryman and J. Fu and T. Husek and J. Jerhot and K. Kampf and M. Zamkovsky and R. Aliberti and G. Khoriauli and J. Kunze and D. Lomidze and R. Marchevski and L. Peruzzo and M. Vormstein and R. Wanke and P. Dalpiaz and M. Fiorini and I. Neri and A. Norton and F. Petrucci and H. Wahl and \{Cotta Ramusino\}, A. and A. Gianoli and E. Iacopini and G. Latino and M. Lenti and A. Parenti and A. Bizzeti and F. Bucci and A. Antonelli and G. Georgiev and V. Kozhuharov and G. Lanfranchi and S. Martellotti and M. Moulson and T. Spadaro and F. Ambrosino and T. Capussela and M. Corvino and \{Di Filippo\}, D. and P. Massarotti and E. Maurice",

note = "Publisher Copyright: {\textcopyright} 2021, The Author(s).",

year = "2021",

month = feb,

day = "1",

doi = "10.1007/JHEP02(2021)201",

language = "English",

volume = "2021",

journal = "Journal of High Energy Physics",

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T1 - Search for π 0 decays to invisible particles

AU - The NA62 Collaboration

AU - Cortina Gil, E.

AU - Kleimenova, A.

AU - Minucci, E.

AU - Padolski, S.

AU - Petrov, P.

AU - Shaikhiev, A.

AU - Volpe, R.

AU - Numao, T.

AU - Velghe, B.

AU - Bryman, D.

AU - Fu, J.

AU - Husek, T.

AU - Jerhot, J.

AU - Kampf, K.

AU - Zamkovsky, M.

AU - Aliberti, R.

AU - Khoriauli, G.

AU - Kunze, J.

AU - Lomidze, D.

AU - Marchevski, R.

AU - Peruzzo, L.

AU - Vormstein, M.

AU - Wanke, R.

AU - Dalpiaz, P.

AU - Fiorini, M.

AU - Neri, I.

AU - Norton, A.

AU - Petrucci, F.

AU - Wahl, H.

AU - Cotta Ramusino, A.

AU - Gianoli, A.

AU - Iacopini, E.

AU - Latino, G.

AU - Lenti, M.

AU - Parenti, A.

AU - Bizzeti, A.

AU - Bucci, F.

AU - Antonelli, A.

AU - Georgiev, G.

AU - Kozhuharov, V.

AU - Lanfranchi, G.

AU - Martellotti, S.

AU - Moulson, M.

AU - Spadaro, T.

AU - Ambrosino, F.

AU - Capussela, T.

AU - Corvino, M.

AU - Di Filippo, D.

AU - Massarotti, P.

AU - Maurice, E.

PY - 2021/2/1

Y1 - 2021/2/1

N2 - The NA62 experiment at the CERN SPS reports a study of a sample of 4 × 109 tagged π0 mesons from K+ → π+π0(γ), searching for the decay of the π0 to invisible particles. No signal is observed in excess of the expected background fluctuations. An upper limit of 4.4 × 10−9 is set on the branching ratio at 90% confidence level, improving on previous results by a factor of 60. This result can also be interpreted as a model- independent upper limit on the branching ratio for the decay K+ → π+X, where X is a particle escaping detection with mass in the range 0.110–0.155 GeV/c2 and rest lifetime greater than 100 ps. Model-dependent upper limits are obtained assuming X to be an axion-like particle with dominant fermion couplings or a dark scalar mixing with the Standard Model Higgs boson.

AB - The NA62 experiment at the CERN SPS reports a study of a sample of 4 × 109 tagged π0 mesons from K+ → π+π0(γ), searching for the decay of the π0 to invisible particles. No signal is observed in excess of the expected background fluctuations. An upper limit of 4.4 × 10−9 is set on the branching ratio at 90% confidence level, improving on previous results by a factor of 60. This result can also be interpreted as a model- independent upper limit on the branching ratio for the decay K+ → π+X, where X is a particle escaping detection with mass in the range 0.110–0.155 GeV/c2 and rest lifetime greater than 100 ps. Model-dependent upper limits are obtained assuming X to be an axion-like particle with dominant fermion couplings or a dark scalar mixing with the Standard Model Higgs boson.

KW - Beyond Standard Model

KW - Exotics

KW - Fixed target experiments

KW - Rare decay

UR - https://www.scopus.com/pages/publications/85101791870

U2 - 10.1007/JHEP02(2021)201

DO - 10.1007/JHEP02(2021)201

M3 - Article

AN - SCOPUS:85101791870

SN - 1126-6708

VL - 2021

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

IS - 2

M1 - 201

ER -

Search for π ⁰ decays to invisible particles

Abstract

Keywords

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