Results of a neutrino oscillation experiment performed at a meson factory beam-stop

Technical Report · Sat Apr 01 04:00:00 EST 1989

DOI:https://doi.org/10.2172/6284494· OSTI ID:6284494

Mitchell, J. W.

This document describes a neutrino oscillation experiment performed at the Los Alamos Meson Physics Facility. The oscillation mode searched for is /bar /nu///sub ..mu../ ..-->.. /bar /nu///sub e/. The first chapter is a review of the known properties of the neutrino and a description of the phenomenon of neutrino oscillation. Previous experimental limits on this unobserved phenomenon are also given. The second chapter describes the experimental apparatus used by the E645 experiment to detect neutrinos produced in the LAMPF beam stop. The salient features of the detector are its large mass (20 tons of CH/sub 2/), its fine segmentation (to allow good particle tracking), good energy resolution, its recording of the history both before and after tracks appear in the detector, an active cosmic-ray anticoincidence shield, and 2000 gm/cm/sup 2/ of passive cosmic-ray shielding. It is located 26.8 m from the neutrino source, which has a mean neutrino energy of 40 MeV. The third chapter details the reduction of the 1.3 million event data sample to a 49 event sample of neutrino candidates. Principle backgrounds are Michel electrons from stopping cosmic-ray muons and protons from np elastic scattering by cosmic-ray neutrons. The fourth chapter explains how background levels from neutrino-nuclear scattering are predicted. The result of a maximum-likelihood analysis reveals no evidence for oscillation. 90% confidence levels are set at deltam/sup 2/ = .10 eV/sup 2/ for large mixing and sin/sup 2/(2theta) = .014 for large deltam/sup 2/. 82 refs., 18 figs., 55 tabs.

• Research Organization: Los Alamos National Lab., NM (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6284494
• Report Number(s): LA-11539-T; ON: DE89010234
• Country of Publication: United States
• Language: English

Related Subjects

440104 -- Radiation Instrumentation-- High Energy Physics Instrumentation
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
645102* -- High Energy Physics-- Particle Interactions & Properties-Experimental-- Weak Interactions & Properties
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BARYONS
BOSONS
COSMIC MUONS
COSMIC NEUTRONS
COSMIC RADIATION
CROSS SECTIONS
DATA ACQUISITION SYSTEMS
DETECTION
ELEMENTARY PARTICLES
FERMIONS
HADRONS
HISTORICAL ASPECTS
IONIZING RADIATIONS
LEPTONS
LIQUID SCINTILLATION DETECTORS
MEASURING INSTRUMENTS
MESONS
MUONS
NEUTRINO OSCILLATION
NEUTRONS
NUCLEONS
PARTICLE IDENTIFICATION
RADIATION DETECTORS
RADIATIONS
SCINTILLATION COUNTERS