Experimental investigations in particle physics at intermediate energies

Technical Report · Tue Oct 31 04:00:00 EST 1989

DOI:https://doi.org/10.2172/5400651· OSTI ID:5400651

Auerbach, L. B.; Highland, V. L.; Martoff, C. J.; McFarlane, K. W.; Buchholz, P.; Sivertz, M. B.

The major emphasis of this project continues to be on fundamental symmetries and parameters of the Standard Model. The primary project is BNL E791, a search for the decay K{sub L}{sup 0} {yields} {mu}e, which would violate the rule of separate lepton number conservation. The technique uses a drift-chamber spectrometer, with particle identification, picking out candidate decays from 2-particle triggers by measuring the two-particle invariant mass m, and the collinearity angle {Theta}{sub c}. For reconstructed K{sub L}{sup 0} {yields} {pi}{sup +}{pi}{sup {minus}} decays the rms resolution in m was {approximately}1.4 MeV/c{sup 2}, and in {Theta}{sub c} it was {approximately}0.3 mrad; these values match the design specifications. All the data from the 1988 run of E971 have been analyzed for K{sub L}{sup 0} {mu}e, K{sub L}{sup 0} {yields} {mu}e, K{sub L}{sup 0} {yields} {mu}{mu}, and K{sub L}{sup 0} {yields} ee events, and the results submitted for publication. We find an upper limit from the 1988 data for the branching fraction of K{sub L}{sup 0} {yields} {mu}e of 2.2 {times} 10{sup {minus}10} and a limit of 3.1 {times} 10{sup {minus}10} for K{sub L}{sup 0} {yields} ee. We also measured the branching fraction for K{sub L}{sup 0} {mu}{mu} to be (5.8 {plus minus} 0.6 {plus minus} 0.4) {times} 10{sup {minus}9}, with a sample of 87 events. Our limits are the best reported. The limit on the decay K{sub L}{sup 0} {yields} {mu}e places a lower limit on the mass of a new particle mediating such decays of 50 TeV. The other neutrino work at Los Alamos, E764, will result in a final publication. Calculations are being completed of the neutrino flux, necessary for the measurement of the {nu}{sub {mu}} {sup 12}C inclusive cross sections. These will be the best measurements of {nu}-nuclear scattering.

• Research Organization: Temple Univ., Philadelphia, PA (USA). Dept. of Physics
• Sponsoring Organization: DOE/ER
• DOE Contract Number: FG02-88ER40389
• OSTI ID: 5400651
• Report Number(s): DOE/ER/40389-62; ON: DE90002565
• Country of Publication: United States
• Language: English

Related Subjects

645100* -- High Energy Physics-- Particle Interactions & Properties-Experimental
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BOSONS
BRANCHING RATIO
DECAY
DETECTION
DOCUMENT TYPES
ELEMENTARY PARTICLES
HADRONS
HIGH ENERGY PHYSICS
INTERACTIONS
KAONS
LEPTON-LEPTON INTERACTIONS
MATHEMATICAL MODELS
MESONS
NEUTRINO OSCILLATION
NEUTRINO-ELECTRON INTERACTIONS
NONLUMINOUS MATTER
PARTICLE DECAY
PARTICLE INTERACTIONS
PARTICLE MODELS
PHYSICS
PROGRESS REPORT
PSEUDOSCALAR MESONS
RESEARCH PROGRAMS
STANDARD MODEL
STRANGE MESONS
STRANGE PARTICLES
UNIFIED GAUGE MODELS