The fractions of polarized positive muons thermalizing in diamagnetic environments (fD) and as muonium atoms (fM) have been measured in gas phase water, methanol, hexane, cyclohexane, tetramethylsilane, and the chloro-methanes. In almost every case, fM=0.8 and f=0.2, in contrast to the corresponding fractions measured in condensed media where PM=0.2 and PD=0.6. Unlike condensed phases, there is generally no "lost" polarization in the vapors. Any missing fraction is understood in terms of hyperfine dephasing of Mu during thermalization; a distinctly gas phase effect which disappears at moderately high pressures. Carbon tetrachloride is anomalous in having an unusually low muonium fraction (fM=0.5) in the vapor, but having no muonium in the liquid phase (PD=1.0). Furthermore, the vapor also has a true missing fraction while the liquid does not. The vapor phase results are interpreted in terms of a hot atom/ion reaction model giving either pressure independent yields (fD) as seen in water and the chloro-methanes or pressure dependent values as measured in the hexanes and TMS. That interpretation indicates that hot atom reactions do not account for more than about 30% of the much larger diamagnetic fractions seen in condensed phases, suggesting that radiation-induced spur effects are predominant in determining thermal fractions in condensed media. / Science, Faculty of / Chemistry, Department of / Graduate

This thesis describes the first measurement of the Lamb shift in n=2 muonium. The muonium atom is a hydrogen-like bound state of two leptons (µ⁺e⁻), both of which are believed to be point-like particles. The point-like nature of the constituent particles simplifies and reduces the uncertainty of the application of quantum electrodynamics (QED) to the calculation of the Lamb shift in the muonium atom. Measurements of the Lamb shift in hydrogen disagree with the predictions of theory by a few standard deviations; however, theoretical predictions also disagree with each other, partly because of difficulties associated with the treatment of the proton structure. Thus a measurement in the muonium system of similar precision to those already made in the hydrogen system will be a valuable test of QED. The present experiment is not intended to test QED. It is an investigation of the methods and techniques necessary to surmount the difficulties presented by the nature of muonium. The available number of muonium atoms is about 10⁺¹º times less than that of hydrogen used by Lamb in his first measurement. The value obtained for the n=2 muonium Lamb shift 1070⁺¹²₋₁₅ MHz. The uncertainty quoted is statistical at the 68% confidence level. Systematic effects were found to contribute to a further 2 MHz uncertainty. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Muonium can be regarded as an isotopic analogue of the hydrogen atom, with a positive muon replacing the proton. This thesis is concerned with searches for muonium in weak transverse and zero magnetic fields in a variety of non-magnetic oxide insulators with few nuclear moments, and in diamond, a semiconductor. The technique of Muon Spin Rotation (µSR) was used, which can be thought of in analogy with NMR and EPR. It relies on measuring the direction of the muon spin with time via the unique signature of the parity violating decay of the muon, in which its decay positron is emitted preferentially along the muon spin direction. This can provide a sensitive measure of the interaction of the muon spin with its environment. Muonium has been searched for successfully in ɑ-quartz, fused quartz., hexagonal and fused germanium dioxide, magnesium oxide, and diamond; and unsuccessfully in tetragonal germanium dioxide, rutile, strontium titanate, zircon, and beryl. All the samples save the quartzes showed a large "missing fraction"; that is, not all the initial muon polarization could be accounted for. This indicates that muonium was formed but rapidly depolarized. The missing fractions were found to be very strongly temperature dependent in strontium titanate but only weakly in rutile. At room temperature, the observed muonium fractions were: ɑ-quartz and fused quartz (65±5)%, hexagonal germanium dioxide <2%, fused germanium dioxide (10±4)%, magnesium oxide (30±10)%, and diamond (33± 4)%. It is noteworthy that the fractions are very different in quartz and germanium dioxide, despite their structural analogy. The observation of muonium in diamond represents the first time that muonium has been seen in a room temperature semiconductor. A spin-Hamiltonian new to µSR was found in low-temperature ɑ-quartz and hexagonal germanium dioxide, in which the hyperfine interaction is completely anisotropic. In low-temperature ɑ-quartz in zero magnetic field this interaction gives rise to three signals whose frequencies are orientation independent, but whose amplitudes are strongly orientation dependent By studying the orientation dependence it was determined that muonium occupies a site which is identical with that seen for hydrogen in EPR studies. This was the first time that muonium was shown to behave just like an isotope of hydrogen in a solid. In hexagonal GeO₂, eight frequencies were observed at 6K, in marked contrast to the observation of only three frequencies in structurally analogous ɑ-quartz. The interpretation of this is that there are three or four different sites, the exact nature of which has not been determined. / Science, Faculty of / Chemistry, Department of / Graduate

An experiment resulting in the reduction of the upper limit for muonium (µ+e⁻) conversion to antimuonium (µ⁻e*) is described. The limit obtained for the effective four fermion coupling constant is G < 42GF (95% confidence level). The muon in a system initially formed as muonium and evolving under the most favorable conditions will thus be identifiable as a negative particle in less than 4% of the observed decays. The results improve by over one order of magnitude the best previous limit obtained from a search for e⁻e⁻ ->µ⁻µ⁻ interactions. Neither process is expected to exist if an additive conservation law is obeyed by muon number. The present status of the theory of electroweak interactions, as it pertains to muonium conversion, is reviewed. It is shown that muon number noncohservation can be accommodated in a variety of ways, some of which might allow a value for G of 0.1GF. The steps that were taken to make the present experiment as sensitive as possible are detailed. The major improvement over previous conversion experiments is the use of fine silica powder in carefully arranged layers to allow muonium to exist for a large fraction of its lifetime in vacuum, where conversion is not highly suppressed. Another important facet of the technique, which is described in detail, is the use of an intense beam of surface muons with a stopping density previously unattainable. A chapter on the analysis of the data contains a quantitative discussion of the processes which must occur for conversion to be detected. The numbers derived there are essential to the establishment of a realistic limit on the coupling of muonium to antimuonium. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

No description available.

The rate constants of the abstraction reaction Mu + HBr —• MuH + Br were measured using the well established μSR technique at TRIUMF. Measurements were made at various temperatures between 170 and 480 K, and fit to the Arrhenius equation both with and without an additional T½ dependence. The rate constants obtained were k(T) = (5.101 ± 0.106) x 10⁻¹¹ exp{-(0.560 ± 0.110) kcal mol⁻¹/RT} and k(T) = (0.183 ± 0.005) x 10⁻¹¹T½exp{-(0.286± 0.014) kcal mol⁻¹/RT} cm³ molecule⁻¹ s⁻¹. The low activation energy for such an exothermic reaction indicates that the barrier on the Mu + HBr surface is early. Kinetic isotope effects of the H/Mu + HBr reactions along with a lack of curvature in the Mu + HBr Arrhenius plot suggest that tunneling is relatively unimportant down to 170 K. / Science, Faculty of / Chemistry, Department of / Graduate

abstract: The muon problem of flavor physics presents a rich opportunity to study beyond standard model physics. The as yet undiscovered bound state (μ+μ-), called true muonium, presents a unique opportunity to investigate the muon problem. The near-future experimental searches for true muonium will produce it relativistically, preventing the easy application of non-relativistic quantum mechanics. In this thesis, quantum field theory methods based on light-front quantization are used to solve an effective Hamiltonian for true muonium in the Fock space of |μ+μ-> , |μ+μ-γ> , |e+e->, |e+e-γ>, |τ+τ-> , and |τ+τ-γ> . To facilitate these calculations a new parallel code, True Muonium Solver With Front-Form Techniques (TMSWIFT), has been developed. Using this code, numerical results for the wave functions, energy levels, and decay constants of true muonium have been obtained for a range of coupling constants α. Work is also presented for deriving the effective interaction arising from the |γγ sector’s inclusion into the model. / Dissertation/Thesis / Doctoral Dissertation Physics 2016

This work is aimed at the understanding of the dynamical behavior of hydrogen in diamond. The investigation was carried out using Transverse Field muon Spin Rotation (TF-SR) and the Longitudinal Field muon Spin Relaxation (LF-SR) techniques. The chemical analogy between hydrogen (p+e-) and muonium (u+e-) enabled the study of the indirect dynamical behavior of hydrogen in diamond. The TF-SR and LF-SR measurements were carried out in an isotopically pure 13C diamond in the temperature ranges 11 mK - 320 K and 10 K - 400 K, respectively. In the TF-SR results, the Prompt Absolute Fraction (PAF) of both diamagnetic and the paramagnetic states are temperature independent. The spin relaxation rate for the state is non-zero and temperature independent, while that of the Mux state is non-zero and temperature dependent. The behavior of indicates that the u+d is immobile, while that of MuT indicates the mobility in diamond. The LF-SR results provide hop rate and associated nuclear hyperfine interaction parameters of the Mut state in diamond. / Physics / M.Sc. (Physics)

This work is aimed at the understanding of the dynamical behavior of hydrogen in diamond. The investigation was carried out using Transverse Field muon Spin Rotation (TF-SR) and the Longitudinal Field muon Spin Relaxation (LF-SR) techniques. The chemical analogy between hydrogen (p+e-) and muonium (u+e-) enabled the study of the indirect dynamical behavior of hydrogen in diamond. The TF-SR and LF-SR measurements were carried out in an isotopically pure 13C diamond in the temperature ranges 11 mK - 320 K and 10 K - 400 K, respectively. In the TF-SR results, the Prompt Absolute Fraction (PAF) of both diamagnetic and the paramagnetic states are temperature independent. The spin relaxation rate for the state is non-zero and temperature independent, while that of the Mux state is non-zero and temperature dependent. The behavior of indicates that the u+d is immobile, while that of MuT indicates the mobility in diamond. The LF-SR results provide hop rate and associated nuclear hyperfine interaction parameters of the Mut state in diamond. / Physics / M.Sc. (Physics)

No description available.