G. M. Marshall
A5106917614- Muon and positron interactions and applications
- Atomic and Molecular Physics
- Particle physics theoretical and experimental studies
- Particle accelerators and beam dynamics
- Quantum Chromodynamics and Particle Interactions
- Neutrino Physics Research
- Quantum, superfluid, helium dynamics
- Nuclear physics research studies
- High-Energy Particle Collisions Research
- Atomic and Subatomic Physics Research
- Nuclear Physics and Applications
- Dark Matter and Cosmic Phenomena
- Chemical Synthesis and Characterization
- Advanced Chemical Physics Studies
- Ammonia Synthesis and Nitrogen Reduction
- Chemical Reactions and Isotopes
- Cold Atom Physics and Bose-Einstein Condensates
- Particle Detector Development and Performance
- Plasma Diagnostics and Applications
- Superconducting Materials and Applications
- Fusion materials and technologies
- X-ray Spectroscopy and Fluorescence Analysis
- Radioactive Decay and Measurement Techniques
- Cold Fusion and Nuclear Reactions
- Geological Modeling and Analysis
TRIUMF
2008-2020
BP (Germany)
2000
University of Victoria
1984-1990
European Organization for Nuclear Research
1989
Rutherford Appleton Laboratory
1982
University of British Columbia
1977-1982
This paper introduces a new approach to measure the muon magnetic moment anomaly |$a_{\mu} = (g-2)/2$| and electric dipole (EDM) |$d_{\mu}$| at J-PARC facility. The goal of our experiment is |$a_{\mu}$| using an independent method with factor 10 lower momentum, 20 smaller diameter storage-ring solenoid compared previous ongoing |$g-2$| experiments unprecedented quality storage field. Additional significant differences from present experimental include 1000 transverse emittance beam...
Lepton family number violation is tested by searching for $\mu^+\to e^+X^0$ decays among the 5.8$\times 10^8$ positive muon decay events analyzed TWIST collaboration. Limits are set on production of both massless and massive $X^0$ bosons. The large angular acceptance this experiment allows limits to be placed anisotropic decays, which can arise from interactions violating lepton flavor parity conservation. Branching ratio order $10^{-5}$ obtained bosons with masses 13 - 80 MeV/c$^2$...
Emission of muonium (|$\mu ^+e^-$|) atoms from a laser-processed aerogel surface into vacuum was studied for the first time. Laser ablation used to create hole-like regions with diameter about 270 |$\mu $|m in triangular pattern hole separation range 300–500 $|m. The emission probability sample is at least eight times higher than uniform one.
Muonium atoms have been observed in vacuum after emission from a layer of finely divided silica powder. By extrapolation the decay-positron track, both time and position muon decay are measured, confirming thermal at room temperature. The yields range up to (19 \ifmmode\pm\else\textpm\fi{} 6)% muons stopping layer, depending on its thickness. result is used recalculate upper limit for conversion muonium antimuonium.
The Lamb shift in muonium has been measured for the first time by a beam-foil-spectroscopy radio-frequency technique. value obtained is ${1070}_{\ensuremath{-}15}^{+12}$ MHz, with systematic uncertainty of 2 compared present theoretical 1047.03 MHz.
The TWIST Collaboration has completed a new measurement of the energy-angle spectrum positrons from decay highly polarized muons. A simultaneous muon parameters ρ, δ, and P(μ)(π)ξ tests standard model in purely leptonic process provides improved limits for relevant extensions to model. Specifically, generalized left-right symmetric |(g(R)/g(L))ζ|<0.020 (g(L)/g(R))m(2)>578 GeV/c(2), both 90% C.L.
Results on antiproton absorption at rest in gaseous nitrogen and deuterium are presented from an analysis of approximately 106 events each taken with a magnetic spectrometer. Inclusive features such as pion proton multiplicities spectra presented. Data relating to modes requiring more than one nucleon, the Λ yield, spectrum, exclusive channels p¯d→π−p, ΛK+π− discussed. The fully reconstructable p¯d→π+π−π−p,π+π+ π−π−π−p also show high-energy tail unaccounted for by single nucleon rescattering...
The TWIST Collaboration has measured the Michel parameter rho in normal muon decay, mu(+)--> e(+)nu(e)nu (mu). In standard model, = 3/4. Deviations from this value imply mixing of left- and right-handed electron couplings. We find rho=0.750 80+/-0.000 32(stat) +/- 0.000 97(syst) 23, where last uncertainty represents dependence on eta. This result sets new limits W(L)-W(R) angle left-right symmetric models.
We present a new high precision measurement of parity violation in the weak interaction, using polarized muon decay. The TWIST collaboration has measured $P_\mu^\pi \xi$, where $P_\mu^\pi$ is polarization pion decay and $\xi$ describes intrinsic asymmetry find \xi = 1.00084 \pm 0.00029\,(\textrm{stat.})_{-0.00063}^{+0.00165}\,(\textrm{syst.})$, good agreement with standard model prediction $P_\mu^\pi=\xi=1$. Our result factor 7 more precise than pre-TWIST value, setting limits left-right...
The TWIST Collaboration has completed its measurement of the three muon decay parameters \rho, \delta, and P_\mu\xi. This paper describes our determination which governs shape overall momentum spectrum, controls dependence parity-violating asymmetry. results are \rho=0.74977\pm 0.00012(stat.)\pm 0.00023(syst.) \delta = 0.75049\pm 0.00021(stat.)\pm 0.00027(syst.). These consistent with value 3/4 given for both in standard model, each is over a factor 10 more precise than measurements...
The muon decay parameter delta has been measured by the TWIST collaboration. We find = 0.74964 +- 0.00066(stat.) 0.00112(syst.), consistent with Standard Model value of 3/4. This result implies that product Pmuxi polarization in pion decay, Pmu, and xi falls within 90% confidence interval 0.9960 < 1.0040. It also implications for left-right-symmetric other extensions Model.
Measurements of muonium (${\ensuremath{\mu}}^{+}{e}^{\ensuremath{-}}$) spin relaxation in finely powdered samples ${\mathrm{Al}}_{2}$${\mathrm{O}}_{3}$, MgO, and Si${\mathrm{O}}_{2}$ indicate that the atoms escape powder grains with a high efficiency, regardless ambient temperature powder. In ${\mathrm{Al}}_{2}$${\mathrm{O}}_{3}$ pure He (or Ne) atmosphere at low ($T<30$ K), rate is proportional to fraction surface area not covered by adsorbed (Ne); it postulated (Ne) film on surfaces...
The first observations of Mu (μ+e−) in the solid and liquid phases Ar, Kr, Xe are reported. fraction muons injected into Xe, which form observable Mu, 97%±29%, 57%±10%, 43%±9%, respectively. corresponding fractions 91%±9%, 99%±10%, 79±25%. spin relaxation rate is a factor 10 larger than liquid. effect attributed to nuclear magnetic dipole moments 129Xe 131Xe less effective relaxing where motional narrowing enhanced. hyperfine splittings Kr Ar have been measured an accuracy 0.1% found be...
An alternate approach was used to study the reactions of muonic atoms and molecules in solid layers hydrogen isotopes. Muons stopped a protium layer with small admixture tritium producing \ensuremath{\mu}p atoms. Muon transfer from proton triton generated \ensuremath{\mu}t atoms, which were emitted into deuterium layer. Subsequent epithermal dt\ensuremath{\mu} molecular formation followed by dt fusion gave prompt signal for emission. Fusion time spectra at various concentrations measured...