We search for lepton-flavor-violating τ− → e− α and τ− → μ− α decays, where α is an invisible spin-0 boson. The search uses electron-positron collisions at 10.58 GeV center-of-mass energy with an integrated luminosity of 62.8 fb−1 , produced by the SuperKEKB collider and collected with the Belle II detector. We search for an excess in the lepton-energy spectrum of the known τ− → e− ν̄e ντ and τ− → μ− ν̄μ ντ decays. We report 95% confidence-level upper limits on the branching-fraction ratio Bðτ− → e− αÞ=Bðτ− → e− ν̄e ντ Þ in the range ð1.1–9.7Þ × 10−3 and on Bðτ− → μ− αÞ=Bðτ− → μ− ν̄μ ντ Þ in the range ð0.7–12.2Þ × 10−3 for α masses between 0 and 1.6 GeV=c2 . These results provide the most stringent bounds on invisible boson production from τ decays.

Adachi, I., Adamczyk, K., Aggarwal, L., Ahmed, H., Aihara, H., Akopov, N., et al. (2023). Search for Lepton-Flavor-Violating τ Decays to a Lepton and an Invisible Boson at Belle II. PHYSICAL REVIEW LETTERS, 130(18), 181803 [10.1103/PhysRevLett.130.181803].

Search for Lepton-Flavor-Violating τ Decays to a Lepton and an Invisible Boson at Belle II

Bernieri, E.
Membro del Collaboration Group
;
Branchini, P.
Membro del Collaboration Group
;
Budano, A.
Membro del Collaboration Group
;
Bussino, S.
Membro del Collaboration Group
;
De Pietro, G.
Membro del Collaboration Group
;
Laurenza, M.
Membro del Collaboration Group
;
Martini, A.
Membro del Collaboration Group
;
2023-01-01

Abstract

We search for lepton-flavor-violating τ− → e− α and τ− → μ− α decays, where α is an invisible spin-0 boson. The search uses electron-positron collisions at 10.58 GeV center-of-mass energy with an integrated luminosity of 62.8 fb−1 , produced by the SuperKEKB collider and collected with the Belle II detector. We search for an excess in the lepton-energy spectrum of the known τ− → e− ν̄e ντ and τ− → μ− ν̄μ ντ decays. We report 95% confidence-level upper limits on the branching-fraction ratio Bðτ− → e− αÞ=Bðτ− → e− ν̄e ντ Þ in the range ð1.1–9.7Þ × 10−3 and on Bðτ− → μ− αÞ=Bðτ− → μ− ν̄μ ντ Þ in the range ð0.7–12.2Þ × 10−3 for α masses between 0 and 1.6 GeV=c2 . These results provide the most stringent bounds on invisible boson production from τ decays.
2023
Adachi, I., Adamczyk, K., Aggarwal, L., Ahmed, H., Aihara, H., Akopov, N., et al. (2023). Search for Lepton-Flavor-Violating τ Decays to a Lepton and an Invisible Boson at Belle II. PHYSICAL REVIEW LETTERS, 130(18), 181803 [10.1103/PhysRevLett.130.181803].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/437749
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