Search for long-lived neutral bosons in orthopositronium decay
1991; American Physical Society; Volume: 66; Issue: 19 Linguagem: Inglês
10.1103/physrevlett.66.2440
ISSN1092-0145
AutoresS. Asai, S. Orito, Kotaro Yoshimura, Takeshi Haga,
Tópico(s)Quantum Mechanics and Applications
ResumoWe have searched for orthoposition decay into \ensuremath{\gamma} plus a feebly interacting boson ${\mathit{X}}^{0}$, by looking for a narrow peak in the energy spectrum of single \ensuremath{\gamma} taken under the condition of no additional \ensuremath{\gamma} detected in a hermetic photon detector. No evidence of such decay is observed, resulting in a new upper limit on the branching ratio of 1.1\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}6}$, which is a factor of 60 more stringent than previous limits in the ${\mathit{m}}_{\mathit{x}}$ region below 30 keV. This experiment rules out the existence of light (${\mathit{m}}_{\mathit{X}}$800 GeV) Goldstone-like bosons having electron-coupling constants ${\mathrm{\ensuremath{\alpha}}}_{\mathit{X}\mathit{e}\mathit{e}}$ larger than 1.1\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}11}$.
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