Search for nucleon decay employing particle identification, invariant masses, and complete track reconstruction in a water Cherenkov detector

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:6173040

Seidel, S C

A search is made for nucleon decay via 23 channels having fully reconstructable two- and three-prong final states. Data are recorded with the Irvine-Michigan-Brookhaven 8 kton underground water Cherenkov calorimeter for 512 live days. The analysis technique selects events having invariant masses, residual momenta, and topological configurations consistent with those of the nucleon and its product mesons. The directions and energies of the individual tracks in the contained event sample are resolved. Particles are identified as showering or non-showering based upon their Cherenkov radiation patterns. The event sample is found to be consistent in all respects with that anticipated from atmospheric neutrino interactions. Although seven events pass all requirements for nucleon decay candidates, they are also individually consistent with being atmospheric neutrino background events. They report no evidence of a signal for nucleon decay. A background subtraction is performed, yielding 90% confidence level lower bounds on the nucleon partial lifetimes in the range 0.06 x 5 x 10/sup 32/ years. The latter 69 days of data are recorded with the detector in the first of two phases of light collection enhancement. This thesis documents the design, simulation, and development of the devices (waveshifter plates) which double the light collection in the first phase upgrade.

• Research Organization: Michigan Univ., Ann Arbor (USA)
• OSTI ID: 6173040
• Country of Publication: United States
• Language: English

Related Subjects

645102* -- High Energy Physics-- Particle Interactions & Properties-Experimental-- Weak Interactions & Properties
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BACKGROUND RADIATION
BARYONS
CHERENKOV COUNTERS
COSMIC NEUTRINOS
COSMIC RADIATION
DATA
DECAY
ELEMENTARY PARTICLES
EXPERIMENTAL DATA
FERMIONS
HADRONS
HYDROGEN COMPOUNDS
INFORMATION
IONIZING RADIATIONS
LEPTONS
LIFETIME
LIMITING VALUES
MASSLESS PARTICLES
MEASURING INSTRUMENTS
NEUTRINOS
NUCLEONS
NUMERICAL DATA
OXYGEN COMPOUNDS
PARTICLE DECAY
PROTONS
RADIATION DETECTORS
RADIATIONS
SEMILEPTONIC DECAY
SPACE
UNDERGROUND SPACE
WATER
WEAK PARTICLE DECAY