A measurement of the fraction, f⁺, of right-handed W bosons produced in top quark decays is presented. This analysis is based on a sample corresponding to an integrated luminosity of 370 pb⁻¹, collected by the D⊘ detector at the Fermilab Tevatron pp Collider at √s = 1.96 TeV. The helicity angle, θ*, is reconstructed for each lepton. f⁺ is determined by comparing the cos θ* distribution from the data with that for the expected background and signal for various values of f⁺. The fraction of longitudinal W bosons, f⁰, is assumed to be 0.7 as predicted by the standard model. This yields f⁺ = 0.109 ± 0.094 (stat) ± 0.063 (syst), consistent with the standard model prediction of f⁺ = 3.6× 10⁻⁴. The possibility that both f⁺ and f⁰ stray from standard model values is also investigated. In this case cos θ* distributions for each possible W helicity state, along with the backgrounds, are fit to the cos θ* distribution for the data. The best fit values are f⁺ = 0.82 ± 0.30(stat) and f⁰ = −0.58 ± 0.50(stat).

No description available.

The discovery of neutrino mixing provides the possibility of a non vanishing CP violating phase in the neutrino mixing matrix. CP violation in the leptonic sector can be large enough to explain the matter-antimatter asymmetry in the universe. An indirect probe of CP violation is the experimental measurement of Electric Dipole Moment (EDM). CP violation has been discovered in the quark sector,but it contributes to lepton EDM at the 3-loop level. Neutrino masses can be generated in the standard model via the see-saw mechanism where heavy right-handed neutrinos mix with the weak-basis states. The Majorana nature of the seesaw type neutrinos generates new 2-loop diagrams that lead to a non-vanishing lepton EDM. Only estimates of the resulting EDM have been done in the literature. A full calculation of the 2-loop diagrams and the exact result is presented. / Ph. D.

This dissertation describes the approach taken in measuring two neutrino double beta decay of Cd-116 to the ground state of Sn-116 and in searching for the effective Majorana neutrino mass by placing a lower limit on the half-life for neutrinoless double beta decay of Cd-116 using the powerful technique of a combined tracking chamber and calorimeter with the NEMO-3 detector. The description of the detector, its natural background contamination, and the tools used to perform the analysis are discussed. The single electron channel was used to identify source foil contamination from [beta]-emitters and the electron-gamma channel was used to confirm the previous measurements of Tl-208 and Bi-214 contaminations in the source foil. Using these backgrounds, the two neutrino double beta decay half-life of Cd-116 was measured for the single states dominance hypothesis and the higher states dominance hypothesis. The final data set was defined to be data from Phrase One and Phase Two for the medium and low activity regions. Using 1471 days of data, the values of the half-life for the single data dominance hypothesis and the higher states dominance hypothesis were found. / text

Pektatlyase (Pel-15) aus dem alkalophilen Bodenbakterium Bacillus spec. KSM-P15 ist mit 197 Aminosäuren eines der kleinsten, bekannten β-3-Solenoidproteine. Sie spaltet Polygalakturonsäurederivate in einem Ca2+-abhängigen β-Eliminierungsprozess. Wie bei allen Proteinen dieser Enzymfamilie ist auch die Polypeptidkette von Pel-15 zu einer einsträngigen, rechtsgängigen, parallelen β-Helix aufgewunden. In diesem Strukturmotiv enthält jede Windung drei β-Stränge, die jeweils durch flexible Schleifenbereiche miteinander verbunden sind. Insgesamt acht Windungen stapeln sich in Pel-15 übereinander und bilden entlang der Helixachse flächige, parallele β-Faltblätter aus. Im Bereich dieser β-Faltblätter existiert ein ausgedehntes Netzwerk von Wasserstoffbrückenbindungen, durch das der hydrophobe Kern, der sich im Inneren der β-Helix befindet, vom umgebenden Lösungsmittel abgeschirmt wird. Besondere Abschlussstrukturen an beiden Enden der β-Helix, wie sie typischerweise bei anderen Ver-tretern dieser Strukturklasse ausgeprägt werden, sind in Pel-15 nicht zu beobachten. Stattdessen sind die terminalen Bereiche der β-Helix über Salzbrücken und hydrophobe Seitenkettenkontakte stabilisiert. In der vorliegenden Dissertation wurde die Pektatlyase Pel-15 hinsichtlich ihres Faltungsgleichgewichtes, ihrer enzymatischen Aktivität und der Kinetik ihrer Strukturbildung charakterisiert. In eine evolutionär konservierte Helixwindung wurden destabilisierende Mutationen eingeführt, und deren Auswirkungen mittels spektroskopischer Methoden analysiert. Die Ergebnisse zeigen, dass Pel-15 in Gegenwart des Denaturierungsmittels Guanidiniumhydrochlorid einen hyperfluoreszenten Gleichgewichtsustand (HF) populiert, der nach Messungen von Faltungs- und Entfaltungskinetiken ein konformationelles Ensemble aus den Zuständen HFslow und HFfast darstellt. Diese HF-Zustände sind durch eine hohe Aktivierungsbarriere voneinander getrennt. In Rückfaltungsexperimenten populieren nur etwa 80 % der faltenden Moleküle den Zwischenzustand HFslow, der mit einer Zeitkonstante von ca. 100 s zu HFfast weiterreagiert. Die Denaturierungsmittelabhängigkeit dieser Reaktion ist sehr gering, was eine trans-/cis-Prolylisomerisierung als geschwindigkeitslimitierenden Schritt nahelegt. Die Existenz eines cis-Peptides in der nativen Struktur macht es erforderlich, den denaturierten Zustand als ein Ensemble kinetisch separierter Konformationen, kurz: DSE, zu betrachten, das durch die Spezies Ufast und Uslow populiert wird. Nach dem in dieser Arbeit aufgestellten „Minimalmodell der Pel-15 Faltung“ stehen die HF-Spezies (HFslow, HFfast) mit den Konformationen des DSE in einem thermodynamischen Kreisprozess. Das Modell positioniert HFfast und die native Konformation N auf die „native Seite“ der Aktivierungsbarriere und trägt damit der Tatsache Rechnung, dass die Gleichgewichtseinstellung zwischen diesen Spezies zu schnell ist, um mit manuellen Techniken erfasst zu werden. Die hochaffine Bindung von Ca2+ (Kd = 10 μM) verschiebt sich das Faltungsgleichgewicht bereits in Gegenwart von 1 mM CaCl2 soweit auf die Seite des nativen Zustandes, das HFfast nicht länger nachweisbar ist. Entgegen anfänglicher Vermutungen kommt einer lokalen, evolutionär konservierten Disulfidbrücke im Zentrum der β-Helix eine wichtige Stabilisierungsfunktion zu. Die Disulfidbrücke befindet sich in einem kurzen Schleifenbereich der β-Helix nahe dem aktiven Zentrum. Obwohl ihr Austausch gegen die Reste Val und Ala die freie Stabilisierungsenthalpie des Proteins um ca. 10 kJ/mol reduziert, lässt die Struktur im Bereich der Mutationsstelle keine gravierende Veränderung erkennen. Auch die katalytisch relevante Ca2+-Bindungsaffinität bleibt unbeeinflusst; dennoch zeigen Enzymaktivitätstests für VA-Mutanten eine Reduktion der enzymatischen Aktivität um fast 50 % an. Die evolutionär konservierte Helixwindung im Allgemeinen und die in ihr enthaltene Disulfidbrücke im Besonderen müssen nach den vorliegenden Ergebnissen also eine zentrale Funktion sowohl für die Struktur des katalytischen Zentrums als auch für die Strukturbildung der β-Helix während der Faltungsreaktion besitzen. Die Ergebnisse dieser Arbeit finden in mehreren Punkten Anklang an Faltungseigenschaften, die für andere β -Helixproteine beschrieben wurden. Vor allem aber prädestinieren sie Pel-15 als ein neues, β-helikales Modellprotein. Aufgrund seiner einfachen Topologie, seiner niedrigen Windungszahl und seiner hohen thermodynamischen Stabilität ist Pel-15 sehr gut geeignet, die Determinanten von Stabilität und Strukturbildung des parallelen β-Helix-Motivs in einer Auflösung zu studieren, die aufgrund der Komplexität bestehender β-helikaler Modellsysteme bislang nicht zur Verfügung stand. / Pectate lyase Pel-15 was isolated from alcaliphlic Bacillus spec. strain KSM-P15. Like all pectate lyases Pel-15 binds and subsequently cleaves polygalacturonic acid, the main pectic compound in plant cell walls and middle lamellae, in a Ca2+ dependent beta-elimination reaction. With 197 amino acids and a molecular mass of only 21 kDa the protein is one of the smallest right-handed parallel beta-helical proteins known today. Polypeptide chains that are classified into this structural family adopt super-helical folds in which each “solenoid stack” consists of three beta-structured regions that are connected by flexible turn segments. Along its longitudinal axis the right-handed parallel beta-helix thus comprises three elongated parallel beta-sheets that are stabilized by an extensive network of hydrogen bonds wrapping around the densely packed hydrophobic core. Together with the shield-like arrangement of hydrogen bonds this hydrophobic core is considered as the main contributor to an exceptionally high stability that is a common feature of all beta-helical proteins. In contrast to most right-handed parallel beta-helices, Pel-15 is devoid of any terminal capping domains and laterally associated secondary structure. Therefore, this protein is considered to be a promising model protein of a pure beta-helix which will help to understand the determinants of both parallel beta-sheet formation and stability. In the dissertation at hand optical spectroscopic methods were used to assess the enzymatic activity, the folding/unfolding equilibrium and the kinetic mechanism of structure formation in neutral buffered solutions. Results indicate that Pel-15 populates a hyper-fluorescent equilibrium intermediate (HF) that is effectively populated in presence of the denaturing agent guanidinium hydrochloride (GdmCl). According to kinetic folding and unfolding experiments HF is not only an essential on-pathway intermediate but has to be considered as a conformational ensemble in which several hyperfluorescent states are in thermodynamic equilibrium with each other. According to their existence in kinetic folding trajectories these different HF-species were termed HFslow and HFfast. The activation energy between both states is remarkably high leading to a time constant of about 100 seconds for the reaction HFslow ⇆ HFfast. Since native Pel-15 contains an energetically disfavoured cis-prolyl peptide between A59 and P60 it is proposed that HFslow and HFfast differ in their prolyl peptide conformations. Two main results emerge from this dissertation. First, an extensive study of the Pel-15 folding- and unfolding behaviour facilitated the proposal of a “minimal folding model”. According to this model the HF-states and the according denatured species Uslow and Ufast are aligned into a thermodynamic circle. This implies that unfolded polypeptide chains reach the HF-ensemble via parallel folding trajectories. Since the native conformation N together with HFfast are on the same side of the activation barrier, it is the reaction HFslow ⇆ HFfast that is the rate limiting step in the folding reaction of Pel-15. Second, the importance of an evolutionarily conserved disulfide bond in the central region of Pel-15 was tested by site directed mutagenesis and subsequent spectroscopic characterization. The exchange of the disulfide against a hydrophobic pair of alanine and valine decreases the folding free energy by about 10 kJ/mol. Although this value is unexpectedly high, structural perturbations around both mutational positions are small as was deduced from X-Ray crystallography. Interestingly, the stability decrease is accompanied by a major loss of enzymatic activity while the Ca2+ binding affinity is not significantly affected. It is therefore concluded that the allosterically relevant disulfide bond stabilizes long-range interactions that stabilize several adjacent solenoid turns near the N-terminus of the protein. Indeed, planar stacking interactions are perturbed and flexibility of N-terminal loops is increased once the disulfide bond is removed. This dissertation establishes Pel-15 as a novel beta-helical model protein and – even more important – smoothes the way for a generally accepted perspective on the formation and stability of parallel beta-sheet proteins.

Le Modèle Standard de la physique des particules a été renforcé par la récente découverte du très attendu boson de Higgs. Le modèle standard cosmologique a lui relevé le défi de la haute précision des observations cosmologiques et des expériences d'astroparticules. Toutefois, ces deux modèles standards sont encore confrontés à plusieurs problèmes théoriques, comme le problème de naturalité dans le secteur de Higgs du Modèle Standard, ainsi que des problèmes observationnels à l'image des nombreuses preuves de l'existence d'un genre inconnu de matière, appelé Matière Noire, qui représenterait la majeure partie du contenu en matière de l'Univers. Les tentatives visant à résoudre ces problèmes ont conduit au développement de nouveaux modèles physiques au cours des dernières décennies. La supersymétrie est un de ces modèles qui traite du problème du réglage fin dans le secteur de Higgs et fournit de bons candidats à la Matière Noire. Les expériences actuelles de physique des hautes énergies et de haute précision offrent de nombreuses possibilités pour contraindre les modèles supersymétriques. C'est dans ce contexte que cette thèse s'inscrit. En considérant le Modèle Standard Supersymétrique Minimal (MSSM), l'extension supersymétrique la plus simple du Modèle Standard, et son candidat à la Matière Noire, le neutralino, il est montré que les contraintes obtenues en collisionneur pourraient fournir des informations sur une période de l'Univers jeune, l'ère inflationnaire. Il est également démontré que la Détection Indirecte de Matière Noire, en dépit de plusieurs inconvénients, peut se révéler être une technique efficace pour explorer les modèles de Matière Noire supersymétrique. Au-delà du MSSM il est montré que des caractéristiques uniques du candidat à la Matière Noire dans le NMSSM peuvent être explorées aux collisionneurs. L'étude d'un modèle supersymétrique avec une symétrie de jauge étendue, le UMSSM, est également développée. Les caractéristiques d'un autre candidat de la matière noire de ce modèle, le sneutrino droit, sont analysées. Des contraintes plus générales telles que celles provenant d'observables de basse énergie sont finalement prise en compte. / The Standard Model of particle physics has been strengthened by the recent discovery of the long-awaited Higgs boson. The standard cosmological model has met the challenge of the high precision observations in comology and astroparticle physics. However these two standard models face both several theoretical issues, such as the naturalness problem in the Higgs sector of the Standard Model, as well as observational issues, in particular the fact that an unknown kind of matter called Dark Matter accounts for the majority of the matter content in our Universe. Attempts to solve such problems have led to the development of New Physics models during the last decades. Supersymmetry is one such model which addresses the fine-tuning problem in the Higgs sector and provides viable Dark Matter candidates. Current high energy and high precision experiments give many new opportunities to probe the supersymmetric models. It is in this context that this thesis is written. Considering the Minimal Supersymmetric Standard Model (MSSM), the simplest supersymmetric extension of the Standard Model of particle physics, and its conventional Dark Matter candidate, the neutralino, it is shown that collider constraints could provide informations on the very early Universe at the inflation area. It is also demonstrated that the Indirect Detection of Dark Matter, despite several drawbacks, can be a powerful technique to probe supersymmetric Dark Matter models. Beyond the MSSM it is shown that unique characteristics of the Dark Matter candidate in the NMSSM could be probed at colliders. The study of a supersymmetric model with an extended gauge symmetry, the UMSSM, is also developed. The features of another Dark Matter candidate of this model, the Right-Handed sneutrino, are analysed. More general constraints such as those coming from low energy observables are finally considered in this model.

Práce je věnována modelování mikrovlnných rezonátorů z metamateriálů (materiálů se záporným indexem lomu). V úvodu je rozebráno, co metamateriály jsou, jak se vytvářejí a které jejich vlastnosti jsou podstatné při návrhu rezonátorů. Následuje návrh planárního rezonátoru z metamateriálů. Pro tento účel byly naprogramovány funkce počítající rozměry jednotlivých součástí struktury. Simulace navržené struktury probíhala v programu Zeland IE3D. Simulované struktury byly optimalizovány s ohledem na požadované kmitočty rezonance. První rezonátor sestával z jedné elementární buňky, druhý ze dvou buněk, naladěných na rozdílné kmitočty. Rezonátory byly vyrobeny a experimentálně byly ověřeny jejich vlastnosti.

Cette thèse contient deux parties distinctes, reliées par le thème de l’étude géométrique du problème à trois corps. La première partie présente un point de vue sur les enjeux et les perspectives liés à la diffusion des mathématiques, et illustre ce point de vue à l’aide de deux projets de diffusion « grand public » : une exposition virtuelle autour de la mécanique céleste et du problème à trois corps, et un duo de contes mathématiques pour enfants, l’un sur la forme de la lune, et l’autre sur l’enlacement de courbes fermées. La présentation de ces projets est suivie d’une analyse a priori et d’une étude des observations recueillies lors de différentes expérimentations auprès de publics variés. La deuxième partie est consacrée à l’étude – théorique et numérique – de l’enlacement des trajectoires de quelques systèmes dynamiques sur la 3-sphère, et en particulier de certaines instances du problème à trois corps. On y présente d’abord le problème à trois corps restreint, plan, circulaire, en s’intéressant tout particulièrement au cas où une des deux primaires disparait. On se ramène ainsi à un flot sur la 3-shpère dont on connaît explicitement des sections de Birkhoff en disque ou en anneau, et on met en lumière des éléments qui tendent à montrer le caractère lévogyre de ce flot. On explore ensuite, à l’aide de simulations numériques, la possibilité que le système reste lévogyre sur un domaine assez éloigné de ce cas dégénéré. Enfin, on s’intéresse aux flots sur la 3-sphère qui admettent une section de Birkhoff en disque et on traduit la notion d’enlacement de mesures invariantes pour le flot en termes d’enroulement de mesures invariantes pour le difféomorphisme de premier retour. / This thesis contains two distinct parts, connected by the subject of the geometric study of the three body problem.The first part presents a point of view about the stakes and prospects of the popularization of mathematics, and it illustrates this point of view with two projects of popularization for a general public : a virtual exhibition about celestial mechanics and the three body problem, and a pair of mathematical tales for children, one about the shape of the moon, and the other about the linking number of two closed curves. The presentation of these projects is followed by an initial analysis and by a study of the observations collected during different experimentations towards various publics. The second part is devoted to the theoretical and computational study of the linking number of trajectories from a few dynamical systems on the 3-sphere, and in particular from some cases of the restricted three body problem. We first present the planar, circular, restricted three body problem, with a particular attention to the case where one of the two heavy bodies vanishes. We thus restrict ourselves to a flow on the 3-shpere for which disk-like or annular-like Birkhoff sections are explicitely known, and we bring to light evidences of the right-handedness of this flow. Then we investigate, with the help of computer simulations, the possibility for the system to stay right-handed over a domain rather distant from this degenerate case. Finally, we consider the flows on the 3-sphere which admit a disk-like Birkhoff section, and we translate the notion of linking for measures that are invariant by a flow into the notion of winding for measures that are invariant by the first return map on the disk.

The diploma thesis deals with metamaterial structures. Metamaterials are periodic structures, which have got permittivity or permeability, eventually both parameters, negative. Test is applied on three basic structures: Split Loop Array; Spiral Array a Double Spiral Array. For each structure is made dispersion diagram and are monitored S – parameters. Test is run in Ansoft High Frequency Structure Simulator and CST Microwave Studio software. Are monitored bandgaps and when structure is as left – handed medium or right – handed medium. Results are compared with results in literature.

Experiments on neutrino oscillations have confirmed that neutrinos have small, but non-zero masses, and that the interacting neutrino states do not have definite masses, but are mixtures of such states.The seesaw models make up a group of popular models describing the small neutrino masses and the corresponding mixing.In these models, new, heavy fields are introduced and the neutrino masses are suppressed by the ratio between the electroweak scale and the large masses of the new fields. Usually, the new fields introduced have masses far above the electroweak scale, outside the reach of any foreseeable experiments, making these versions of seesaw models essentially untestable. However, there are also so-called low-scale seesaw models, where the new particles have masses above the electroweak scale, but within the reach of future experiments, such as the LHC.In quantum field theories, quantum corrections generally introduce an energy-scale dependence on all their parameters, described by the renormalization group equations. In this thesis, the energy-scale dependence of the neutrino parameters in two low-scale seesaw models, the low-scale type I and inverse seesaw models, are considered. Also, the question of whether the neutrinos are Majorana particles, \ie , their own antiparticles, has not been decided experimentally. Future experiments on neutrinoless double beta decay could confirm the Majorana nature of neutrinos. However, there could also be additional contributions to the decay, which are not directly related to neutrino masses. We have investigated the possible future bounds on the strength of such additional contributions to neutrinoless double beta decay, depending on the outcome of ongoing and planned experiments related to neutrino masses. / QC 20110812