VictorJuiz/thesis huggingface dataset:
Inclusive rare B decays using effective field theories

In this thesis we will discuss several properties of rare decays of B mesons. First we discuss properties of the inclusive radiative decay B —► X 3(5)7, where X(5) stands for any hadronic state containing an s quark. We extend previous studies of this decay, which included perturbative corrections to order a 3 and nonperturbative contributions up to order (AQCD/mb )2 and calculate the O(AQCD/mb)3 contributions to this decay. The values of the nonperturbative parameters entering at this order are unknown, leading to uncertainties in the standard model prediction of this decay. We estimate the size of these nonperturbative uncertainties by varying these parameters in the range suggested by dimensional analysis. We also estimate uncertainties arising from a cut on the photon energy which is required experimentally. Another decay mode investigated is B —> X(5) l+l~. We study the O(AQCD/mb)3 contributions to the leptonic invariant mass spectrum, the forward-backward asymmetry and hadronic invariant mass moments and estimate the resulting uncertainties. We calculate how the size of these uncertainties depend on the value of an experimental cut that has to be applied to eliminate the large background from other B decays. A model independent way to determinate the CKM matrix element |Vub| from the dilepton invariant mass spectrum of the inclusive decay B -> X (u) l +v is presented next. We show that cuts required to eliminate the charm background still allow for a theoretically clean way to determine the CKM matrix element |K,6|- We also discuss the utility of the B —> X s£+£~ decay rate above the V>(2S) resonance to reduce the resulting uncertainties. Finally, we introduce a novel effective theory valid for highly energetic particles. In decays where the phase space is sufficiently restricted such that final state particles have very high energies compared to their mass, the perturbative as well as nonperturbative series diverge. The effective theory presented allows to sum perturbative Sudakov logarithms in a framework that also incorporates the nonperturbative physics in such limits of phase space.

Keywords: Physics
Advisor: Luke, Michael
Quantization of a classical model with symmetry

A theory of quantization is given, for a model with symmetry, as the inverse of dequantization. Dequanrization is defined as tin’ process of extracting the classical mechanics of a model from its quantal counterpart. It is shown that classical dynamics is embedded in quantum dynamics as a constrained subsystem. Thus, classical mechanics is obtained from quantum mechanics without taking limits of large-dimensional representations or letting h —► 0. The embedding shows that, under appropriate conditions, a quantal density can be identified with a classical state. The results are consistent with the conjecture that an algebraic model is quantized by constructing a unitary irrep of its spectrum generating algebra. Quantization of operators not in this algebra is determined by compatibility with dequantization: this method resolves the Dirac problem in a way that avoids the ambiguities of canonical quantization. Geometric quantization is used to express the vector coherent state inducing construction as a theory of quantization. The result provides physically useful quantum models for systems with an algebraic structure and intrinsic degrees of freedom. The results are illustrated by application to the S i (3) model of a rotor. An algebraic model of a rigid rotor is presented, anti the techniques of vector coherent state quantization are applied to give a quantization, including intrinsic degrees of freedom, that is compatible with the geometric structure of the corresponding classical model. An explicit dequantization of the asymmetric top, leading to Euler’s equations, illustrates the consistency of this quantization.

Keywords: Physics
Advisor: Rowe, David J.
The dissociation energy of hydrogen and of deuterium

The ab initio computation and experimental determination of the dissociation energy (Do) of the hydrogen and deuterium molecules has long been an important problem in molecular spectroscopy. Kolos, Monkhorst, and Szalewicz (1986) have calculated D0 with an accuracy of± 0.1 cm-1 while including fine interactions such as relativistic effects, nonadiabatic mixing, and radiative shifts. These terms introduce corrections as small as 0.2 cm-I, and experimental precision must exceed this to test the calculation in all of its aspects. In our experiment, a jet of H2 (or Di) was probed with coherent and tunable radiation at - 84 nm, near the second dissociation limit which leads to the products H(n=2) + H(ls). Molecules in their ground state were exited into the highest vibronic levels of the electronic states B, B', and C, and into the dissociation continuum by tuning the radiation across the dissociation threshold. Metastable H(2s) photofragments were detected by applying a delayed electric field to mix the 2s with 2p states, thereby quenching H(2s) atoms to yield fluorescence at the Lyman-a wavelength. The onset of quenched fluorescence marked the second dissociation limit; from this energy, the atomic 2s-ls interval was subtracted, thus yielding 0 0• We obtained the values D0(Hi) = 36 118.11 ± 0.08 cm·l and D0(Di) = 36 748.38 ± 0.07 cm·l, which are in excellent agreement with the most recent theoretical calculations. Thus, a long-standing discrepancy between experiment and theory has been resolved, and the ab initio calculation of D0 appears to be successful. Finally, from our D0 values, the dissociation energies of the molecular ions were deduced, and they also confirm the latest (1991) ab initio values of D0(H!) and D0(D2).

Keywords: Physics
Advisor: Stoicheff, B.P.
Semiconductors and their heterostructures: Contributions to the theory of electronic and optical properties

We introduce a new scheme to study semiconductor heterostructure electronic states that is more general than common envelope function approaches, allowing full-zone dispersions and often-neglected material differences to be described. This modal scattering formalism offers a “best choice” flux conserving interface connection rule at each energy by identifying a relevant unitary scattering matrix. Calculations of T — A' scattering in GaA s/AlAs structures illustrates the technique. We then construct an efficient twelve mode/eight-band k • p theory that exposes a light and heavy-particle coupling absent in m any other schemes, as well as new transfer matrix contributions; the latter describe interfacial spin-orbit coupling effects and finite basis corrections. This model is employed to predict new transmission resonances in InA s/G aSb interband tunnel structures. We also offer a novel interpretation of the popular envelope function approximation, which emerges from our theory after simplifying assumptions. We then present a simple prescription for a “length gauge” derivation of the electronic contributions to nonlinear optical susceptibilities of crystals. This provides expressions free from the unphysical zero frequency divergences which often plague susceptibility calculations of clean, cold semiconductors. In contrast to a recently presented alternative formalism, the transparent mathematical details of our approach facilitates physical in tempretatio n and analysis; for example, we can easily identify corrections to the commonly quoted noninteracting- electron semiconductor Bloch equations. We also derive the general second and third order semiconductor susceptibilities, whose zero frequency limits can now reveal novel effects not previously discussed. Further, we present a model calculation of third order semiconductor nonlinearities that corrects previously published dispersions, clarifies various zero frequency limits, and corresponds with several known results. Finally, we offer preliminary considerations of the consequences of our results on theoretical descriptions of semiconductor heterostructure optical properties. This includes describing the advantages of a heterostructure analog to our bulk crystal optical response scheme, as well as the benefits of our heterostructure electronic state formalism.

Keywords: Physics
Advisor: Sipe, John
Measurement of the top quark mass with in situ jet energy scale calibration using hadronic W boson decays at CDF-II

We report a measurement of the top quark mass with the upgraded Collider Detector at Fermilab (CDF-II). The top quarks are produced in pairs (tt) in proton-antiproton collisions with a center-of-mass energy of 1.96 TeV. Each top quark decays to a W boson and a bottom quark. We select candidate events in which one W boson decays hadronically and the other decays to an electron or a muon and its associated neutrino. The data sample, which corresponds to an integrated luminosity of 318 pb-1, contains 138 tt candidates. A top quark mass is reconstructed for each event by placing energy and momentum constraints on the top quark pair decay products. We also employ the reconstructed mass of the hadronic W boson decays W —> jj to constrain in situ the largest systematic uncertainty of the top quark mass measurement, the jet energy scale. Monte Carlo tem plates of the reconstructed top quark and W boson mass are produced as a function of the top quark mass and the jet energy scale. The distribution of reconstructed top quark and W boson mass in the data are compared to the Monte Carlo tem plates using a likelihood fit to obtain M top = 173.5 +3.9/-3.8 GeV This constitutes the most precise measurement of the top quark mass to date. This measurement can be used to constrain the mass of the Higgs boson, a central particle in the Standard Model of particle physics that has yet to be observed. We also demonstrate that this new technique reduces naturally the jet energy scale uncertainty as more d a ta is accumulated and thus provides the capability to measure M top with an uncertainty of 2 G eV /c2 or better by the end of the CD F-II experiment.

Keywords: Physics
Advisor: Sinervo, Pekka
A surface distortion decomposition for vector CSAMT data over one-dimensional earth

Single source CSAMT data, also known as vector CSAMT data, has been routinely collected in recent years and processed using the conventional 2-D induction model which does not incorporate galvanic distortion effects, although the importance of these has been widely recognized. The small number of data available in vector CSAMT though, does not allow models that simultaneously incorporate both 2-D induction and local galvanic distortion. Either the 2-D inductive model with no distortion or alternatively a 1-D model with up to two distortion parameters can be used. Two 1-D distortion models were tested that are specialized cases of the general Groom and Bailey’s (1989) M T decomposition method, (A) one which assumes the distortion parameter splitting (s) can be made zero choosing an appropriate coordinate system, and (B) other in terms of polarization ellipses that assumes the distortion parameter shear (e) can be zeroed by rotating the principal axes to the measurement axes. The former produces the distortion parameters twist and shear while the later generates twist and splitting. Computer algorithms were implemented and a data set was used to test the models and later compared with the classical 2- D model. Except for the magnitudes which differ by a scaling factor, the apparent resitivities computed with the three different approaches show very similar electrical distributions but the phases show discrepancies. The distortion parameters distribution of the distortion model (A) for the used data set has a complicated pattern and are frequency dependent. Distortion parameters obtained using model (B) define better the conductive structure and are approximately constant in a reasonable frequency interval. The results of the test suggest that the zero-split assumption is likely not valid while the zero-shear approach is a more realistic one, although further testing is necessary to confirm this.

Keywords: Physics
Advisor: Bailey, Richard
Influence of the quasi-biennial oscillation on interannual variability in the Northern Hemisphere winter stratosphere.

Observations show that the interannual variability of the Northern Hemisphere (NH) extratropical winter stratosphere is strongly correlated with the quasi-biennial oscillation (QBO) of tropical stratospheric winds, particularly during early winter. Most current general circulation models (GCMs) do not exhibit a QBO and therefore do not represent this important mode of tropical-extratropical interaction. In this study we examine the QBO-extratropical correlation using a 150-year GCM simulation in which a QBO occurs. Since no external forcings or interannual variations in sea surface temperatures are imposed, the modelled tropical-extratropical interactions represent an internal mode of atmospheric variability. The QBO itself is spontaneously forced by a combination of resolved and parameterized waves. The effects of this QBO on the climatological mean state and its interannual variability are considered, both by comparison with a control simulation (also 150 years in length, but with no QBO) and by compositing winters according to the phase of the QBO. Careful attention is given to the definition of QBO phase. Comparisons of the model results with observations (reanalysis data) are also made. QBO-induced changes in the climatological state of the model are found to have high statistical significance above the tropopause. In the extratropical winter stratosphere, these mean-state changes arise predominantly from the influence of the QBO on the propagation and dissipation of planetary-scale waves. This behaviour is shown to depend on the seasonal cycle, which argues for the usefulness of considering tropical-extratropical interactions in a GCM context. QBO influence on the interannual variability of the extratropical winter stratosphere is also seasonal, and the tropical-extratropical interaction is sensitive to the phase alignment of the QBO with respect to the annual cycle. This phase alignment is strongly affected by the seasonality of QBO phase transitions, which – due to the QBO being spontaneously generated, rather than having an imposed period – is somewhat realistic in the model. This leads to fluctuations in the strength of the modelled tropical-extratropical interaction occurring on a decadal timescale as an internal mode of atmospheric variability.

Keywords: Physics
Advisor: Shepherd, Theodore G.
Coherent of excitons and continuum excitations in Indium Phosphide

The dynamics of optically generated, coherent electronic excitations in Indium P hosphide at a temperature of 5 K are investigated over a 140 meV energy range near the band gap, using the two-pulse, self-diffracted, degenerate four-wave mixing technique with 30-50 fs near-infra-red pulses and spectrally resolved detection. The coherent dynamics of excitons associated with the fundamental energy gap are investigated under conditions of simultaneous excitation of continuum transitions. Exciton-carrier scattering is shown to produce the dominant source of diffraction for excitons due to excitation-induced dephasing. The dephasing rate of continuum excitations is found to increase abruptly at the threshold energy for LO phonon emission by electrons. Below this threshold energy the dephasing rate is determined to be at least 8 ps-l, whereas above the threshold energy, the dephasing rate is at least 13 ps-'. Near the spin-orbit split-off valence to conduction band transition energy the diffracted spectrum is strongly affected by an interaction between split-off excitons and continuum excitations of heavy and light hole bands. A Fano-like spectral profile is observed in the coherent emission spectrum at the split-off transition and the coherent dynamics is dis- . * 11 cussed in terms of coupled exciton-continuum excitations. The Fano coupling parameter q. which characterizes the spectral profile. is found to decrease as excitation density increases. The interaction matnx elernent between split-off excitons and continuum excitations is determined to be approximately 5 meV, which corresponds to a 130 fs lifetime, over the density range investigated. Observation of the Fano interference phenornenom by fourwave mixing is found to depend on the relative orientation of the electric field polarization vectors. The Fano-like spectral profile is much less prominent for cross-polarized pulses than for CO-polarized pulses. Evidence for Fano interference is also observed by spectrally integrated four-wave mixing; there is no evidence of the interference in the cross-polarized case. At present, the polarization dependence is not understood: therefore, the interaction mechanism is not identified but possible interaction mechanisms that could give rise to Fano interference are discussed.

Keywords: Physics
Advisor: van Driel, Henry
Reprocessing of High Resolution Crustal Seismic Reflection Data from the Abitibi Greenstone Belt

Deep crustal reflection seismic data were collected in the Abitibi Greenstone Belt during the winter of 1987-8 as part of the Lithoprobe Project. Although much reflection energy was visible after initial processing, it was apparent that the stacked section could be improved. In particular, very little reflection energy was imaged in the upper 1 s, making it difficult to correlate deeper reflections with the mapped surface geology. The high resolution line 12A was reprocessed with a particular effort to obtaining a better image of the shallow data. Spectral equalisation of the upper 3 to 4 s and an accurate, complete static solution were found to be the most important steps in the reprocessing. Ground roll proved difficult to attenuate, with velocity filtering showing some promise, although not entirely satisfactory. Neax offset, low frequency vibrator noise was only partially attenuated through spectral equalisation, and may have been caused by subhaxmonic distortion in the vibrator signal. The dip moveout effect was substantial for shallow data in the southern part of the line. Reflection energy is apparent at all travel times in the unstacked data, although most of it does not stack coherently because its amplitude and phase characteristics vary with offset. Reflection energy above 100 Hz could not be imaged as coherent reflection energy after stacking. Reprocessing resulted in great improvement throughout the stacked section, with considerable reflection energy being imaged to 0.5 s. The results of this thesis illustrate the value of detailed processing of deep crusted reflection data in Archaean cratons.

Keywords: Physics
Advisor: West, G. F.
Propositional Representation of Arithmetic Proofs

It is well known that the Boolean functions corresponding to a function computable in polynomial time on inputs of bounded length are computable by Boolean circuits of size polynomial in the bound. Similarly, polynomial length propositional formulas exist representing the truth of an equation t = u between terms involving functions computable in polynomial time, on inputs of bounded length. For certain proof systems whose theory is a set of such equations, there is a propositional proof system such that the representing formulas of a provable equation have polynomial length proofs. If a propositional proof system satisfies certain restrictions, then the arithmetic system such that this is true can be constructed. We prove two specific representation theorems; the first was stated by Cook and is proved here for the first time, and the second, involving polynomial space arithmetic and a natural proof system for the valid formulas of the quantified propositional calculus, is stated and proved here for the first time.

Advisor: Cook, Steve
Critical Pathways Towards Antiracism in an Elementary Knowledge Building Classroom

This research project studies how a critical knowledge building environment might be created and sustained by taking into consideration several factors: (1) the dialogue and patterns of participation within this space; (2) whose knowledge is values and whose is silenced; and (3) the various forms of resistance in the classroom and school where this research takes place. It questions whether knowledge building can help to foster critical antiracism in the classroom, and also looks at how critical antiracism can inform the practice of knowledge building by explicitly recognizing, naming, and questioning the power that exists within the classroom, online and offline. Data was collected from a Knowledge Forum® database, focus group discussions, classroom observations, in-class discussions with the students and teacher, email, and an analysis of the revisions within the Ontario Social Studies curriculum documents from 1998 and 2004 in an attempt to understand the way in which both explicit and hidden curricula are mandated provincially. Also part of this study is the investigation of my role as an antiracist educator/researcher in this project and the various tensions, silencing, and resistance that I encountered throughout this journey. This role is recognized as one of power and powerlessness, depending on with whom, this role is negotiated. I investigate this role through the negotiations with various participants and their explanation of my role as well as through the reflexive process of autoethnography where I frame my role and my location as it is negotiated with the participants, my family, my work, and the process of coming to this project.

Keywords: critical knowledge
knowledge building
antiracism
classroom
autoethnography
Advisor: Goldstein, Tara
Electromagnetic decay of states of high spin and high isospin in fluorine-19

The lowest Jπ =11/2+ state and the lowest two T = 3/2 states In 19F have been located among a number of new resonances in the 15 N(α,γ)19F reaction. The spins and radiative widths of these three new levels have been established by measurements of angular distribution and yield of γ-radiation. Their isospin is inferred from their spins, excitation energies, radiative widths and decay schemes. Measured transition matrix elements are compared with those calculated from shell-model wavefunctions which Include all (sd)3 configurations. Disagreements between 3 experiment and theory indicate that the (sd) description is inadequate for some of the positive parity states in 19F above about 4 MeV in excitation. Arguments are presented for the inclusion of (p) -2 (sd) 5 configurations to account for the properties of these states. The new 11/2+ level and the 7/2+ level at 4.38 MeV (whose spin has been definitely established in the course of this work) are discussed also in terms of a simple adiabatic rotational model for 19F. This model is found to account reasonably well for the excitation energies and transition probabilities of the lowest levels of spins 1/2 to 13/2.

Keywords: Physics
Advisor: Litherland, A. E.