122262979
A Precision Measurement of Muon Decay
The (V-A) structure of the weak interaction was put into the standard model by hand in order to obtain agreement with experiments. These experiments, however, do not rule out relatively large deviations from this structure. Muon decay provides an ideal laboratory to test this structure, being a purely leptonic process. The TRIUMF Weak Interaction Symmetry Test (TWIST) will measure both the energy and emission-angle distribution of positrons from the decay of polarized muons. This will provide a simultaneous determination of the Michel parameters Pμξ, ρ and δ describing muon decay with a precision of a few parts in 104. Stringent limits may then be placed on the coupling constants, as well as the mass and mixing angle of a possible right-handed W boson (WR). In this paper the formalism for muon decay is presented, TWIST is described, and the expected results are discussed.
119708470
TWIST- The TRIUMF weak interaction symmetry test the Michel parameters from μ+ decay
Abstract We propose to make the first high precision measurements of nearly the entire differential spectrum (in energy and angle) of positrons from the decay of polarized muons. The main goal of the experiment is the precise testing of the ( V - A ) structure of electroweak interactions in the framework of the SU (2) L × U (1) model. Highly polarized “surface” μ + from the TRIUMF M13 beamline will enter a large volume, high field superconducting magnet on axis and will stop in a thin target at its center. The e + from the muon decay will be precisely tracked in the magnetic field using small-cell planar drift chambers. This spectrometer has been simulated with GEANT and EGS4 and has been demonstrated to meet the precision requirements.
118743742
Energy Spectra and Charge Ratios of Atmospheric Muons
We present a new measurement of atmospheric muons made during an ascent of the High Energy Antimatter Telescope balloon experiment. The muon charge ratio μ+/μ− as a function of atmospheric depth in the momentum interval 0.3–0.9 GeV/c is presented. The differential μ− fluxes in the 0.3–50 GeV/c range and for atmospheric depths between 4–960 g/cm are also presented. We compare these results with other measurements and model predictions.
117398705
Measurement of the Cosmic-Ray Antiproton Energy Spec- trum with HEAT-pbar
The absolute intensities of cosmic-ray antiprotons have been measured in the energy range between 4.5 and 50 GeV. The data were obtained by the HEAT-pbar instrument, a balloon borne superconducting magnet spectrometer with precise rigidity and multiple energy loss measurement capability. The instrument was flown in the Spring 2000 from Ft. Sumner, NM, at an average atmospheric depth of 7.2 g/cm. Here we briefly describe the instrument and the measurement and outline the analysis of the data which is still ongoing at this time. We will present the result of our analysis and discuss the implications for cosmic-ray propagation models at the conference.
15799053
A Large‐Area CCD Camera for the Schmidt Telescope at the Venezuelan National Astronomical Observatory
We have designed, constructed, and put into operation a large-area CCD camera that covers a large fraction of the image plane of the 1 m Schmidt telescope at Llano del Hato in Venezuela. The camera consists of 16 CCD devices arranged in a 4 × 4 mosaic covering 23 × 35 of sky. The CCDs are 2048 × 2048 LORAL devices with 15 μm pixels. The camera is optimized for drift-scan photometry and objective-prism spectroscopy. The design considerations, construction features, and performance parameters are described in the following paper.
120496581
THE HIGH-ENERGY ANTIMATTER TELESCOPE (HEAT) : AN INSTRUMENT FOR THE STUDY OF COSMIC-RAY POSITRONS
Abstract The HEAT (High-Energy Antimatter Telescope) instrument has been developed for a series of observations in cosmic-ray astrophysics that require the use of a superconducting magnet spectrometer. This paper describes the first configuration of HEAT which is optimized for the detection of cosmic-ray electrons and positrons below 100 GeV. In addition to the spectrometer, a combination of time-of-flight scintillators, a transition radiation detector, and an electromagnetic shower counter, provides particle identification, energy measurement, and powerful discrimination against the large background of protons. The instrument was successfully flown aboard high-altitude balloons in 1994 and 1995. The design and construction of the spectrometer and of the detector systems are described, and the performance of the instrument is demonstrated with data obtained in flight.
55930763
Air Shower Muons and the Atmospheric Neutrino Puzzle
The study of atmospheric neutrinos and their interpretation in terms of oscillations require a detailed theoretical understanding of atmospheric neutrino production. Muon production in the atmosphere is closely coupled with neutrino production, so that measured muon fluxes can be used to calibrate neutrino production calculations. The High-Energy Antimatter Telescope (HEAT) balloon-borne magnet spectrometer was designed for the study of high-energy electrons and positrons in the cosmic-ray flux. It uses an array of redundant particle detectors suitable for the identification of other particle species as well, including muons. During atmospheric ascent of the balloon, air-shower particles have been detected in situ, and in particular the energy spectra of airshower muons have been measured from 0.2 to 50 GeV, as a function of atmospheric depth. This measurement is described, and its implications on our understanding of atmospheric neutrino production are discussed.