Search of spontaneous conversion of muonium to antimuonium

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5220878

Ni, Benwen

Muonium (M or {mu}{sup +}e{sup {minus}}) to antimuonium ({bar M} or {mu}{sup {minus}}e{sup +}) conversion is not allowed in the standard theory of electroweak interactions in which the lepton number of each lepton generation is separately conserved. Several extensions of the standard mode, however, permit the M {yields} {bar M} conversion. Extensions of the standard model with a doubly charged Higgs triplet, for example, allows G{sub M{bar M}}, the coupling constant characterizing the strength of the interaction leading to the conversion, to be as large as 10G{sub F}, where G{sub F} is the Fermi coupling constant. A new experimental search for the spontaneous M {yields} {bar M} conversion, conducted at the Clinton P. Anderson Meson Physics Facility (LAMPF), is described in this thesis. A separated low momentum {mu}{sup +} beam of average intensity 3 {times} 10{sup 5/3} was used to produce M atoms in vacuum by the beam-foil method. The signature of an {bar M} event was a triple coincidence among two cascade muonic X-ray photons from the capture of the {mu}{sup {minus}} from {bar M} by a high-Z target and a secondary electron emitted from the target upon the impact of {bar M}. The photons were detected by a large solid-angle NaI(Tl) detector which had good resolution in energy, time and position. The secondary electrons were electrostatically collected and guided on to a microchannel plate detector (MCP). Observation of the M {yields} {bar M} conversion would indicate that lepton family number is not a separately, additively conserved quantum number and provide a useful probe of new physics beyond the standard model. No {bar M} events in excess of background were observed and the 90% confidence level upper limit of G{sub M{bar M}} is measured to be 6.9G{sub F} which improves the best previous result by a factor of three.

• Research Organization: Yale Univ., New Haven, CT (United States)
• OSTI ID: 5220878
• Country of Publication: United States
• Language: English

Related Subjects

640303* -- Atomic
Molecular & Chemical Physics-- Positronium
Muonium
& Muonic & Mesic Atoms & Molecules
74 ATOMIC AND MOLECULAR PHYSICS
ACCELERATORS
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
ATOMS
BOSONS
CONVERSION
COUPLING CONSTANTS
ELEMENTARY PARTICLES
EXPERIMENT PLANNING
FERMIONS
FIELD THEORIES
LEPTON NUMBER
LEPTONS
LIMITING VALUES
MASSLESS PARTICLES
MATHEMATICAL MODELS
MATTER
MEASURING INSTRUMENTS
MESON FACTORIES
MUONIC ATOMS
MUONIUM
MUONS
MUONS PLUS
NAI DETECTORS
PARTICLE MODELS
PHOTONS
PLANNING
RADIATION DETECTORS
SCINTILLATION COUNTERS
SOLID SCINTILLATION DETECTORS
STANDARD MODEL
UNIFIED GAUGE MODELS
UNIFIED-FIELD THEORIES
WEINBERG-SALAM GAUGE MODEL