Search for invisible decay of orthopositronium

Journal Article · Mon Apr 12 04:00:00 EDT 1993 · Physical Review Letters; (United States)

DOI:https://doi.org/10.1103/PhysRevLett.70.2265· OSTI ID:6872893

Mitsui, T; Fujimoto, R; Ishisaki, Y; Ueda, Y; Yamazaki, Y; Asai, S; Orito, S ^[1]

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1. Department of Physics, Faculty of Science, University of Tokyo, Tokyo 113 (Japan)

Orthopositronium ([ital o]-Ps) decay or conversion into invisible'' final states is searched for by measuring the energy deposited in a hermetic photon detector for each positron produced from [beta][sup +] decay of [sup 22]Na and stopped by an aerogel target. No invisible event is detected for a total of 10[sup 8] stopping positrons, thereby giving an upper limit of 2.8[times]10[sup [minus]6] on the [ital o]-Ps branching ratio, which is 200 times more stringent than previous limits. This experiment excludes an invisible decay as the origin of the reported discrepancy on [ital o]-Ps lifetime, provides a limit of [epsilon][lt]1.5[times]10[sup [minus]8] on the photon--mirror-photon mixing, and rules out millicharged particles lighter than 500 keV.

• OSTI ID: 6872893
• Journal Information: Physical Review Letters; (United States), Journal Name: Physical Review Letters; (United States) Vol. 70:15; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

664500* -- Special Atoms & Molecules-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION
ALKALI METAL ISOTOPES
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
BETA DECAY
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BRANCHING RATIO
DATA
DECAY
ELEMENTARY PARTICLES
ENERGY ABSORPTION
ENERGY SPECTRA
EXPERIMENTAL DATA
FERMIONS
FINAL-STATE INTERACTIONS
INFORMATION
INTERACTIONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LEPTONS
LIFETIME
LIGHT NUCLEI
MATTER
NANOSEC LIVING RADIOISOTOPES
NUCLEAR DECAY
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
PHOTODETECTORS
POSITRONIUM
POSITRONS
RADIOISOTOPES
SENSITIVITY
SODIUM 22
SODIUM ISOTOPES
SORPTION
SPECTRA
TIMING PROPERTIES
VACUUM SYSTEMS
YEARS LIVING RADIOISOTOPES