Title: Study of fake-tau background with the ATLAS experiment Author: Gabriela Martinovicová Institute: Institute of Particle and Nuclear Physics Supervisor: Mgr. Vojtěch Pleskot, Ph.D., Institute of Particle and Nuclear Physics Abstract: The τ-leptons are the important final-state components, not only in the Standard Model processes but also in the processes beyond the Standard Model studied at the ATLAS experiment at CERN. They are characterized by mostly decaying into hadrons with one or three charged particles and, in most cases, with at least one neutral pion in the final-state. Due to their short decay length, only their decay products are observed in the detector. Jets naturally fake hadronically decaying τ leptons, so it is necessary to estimate such a fake-τ background. The Fake Factor method uses a correction factor, called fake factor (FF), measured from the data and applied to the data to estimate the fake-τ background in a given signal region. One of the complications is that FF differs for τ candidates faked by jets derived from quarks or gluons and thus must be measured in the control region with the same fraction of quark jets as in the signal region. The solution to this problem is the universal FF method, which proposed that from the FFs measured in samples with a large difference in the...

Seit über 150 Jahren erscheinen in den statistischen Institutionen thematische Atlanten – bis heute über 2500 Werke. Als «Reiseführer» durch Gesellschaften erzählen sie spannende und vielfältige Geschichten über den Staat, die Menschen und deren Zusammenleben. Gerade im Kontext der Informationsgesellschaft nehmen solche Atlaswerke wieder sprunghaft zu und sprechen dabei ein außerordentlich breites Nutzerspektrum aus allen Berufskreisen an. Ziel der vorliegenden Dissertation war es, durch theoretische und empirische Methoden das Wesen, die geschichtliche Entwicklung und die prägenden Merkmale des «Statistischen Atlas» eingehend zu untersuchen und damit Forschungslücken in der Thematischen Kartographie, der Atlaskartographie und der Statistik zu schließen. Mit Hilfe einer neu entwickelten Definition sowie einer aktuellen Atlasklassifikation können statistische Atlanten eindeutig bestimmt und von verwandten Atlastypen – etwa dem National-, dem Regional- oder dem Planungsatlas – im Hinblick auf die korrekte Einordnung in Bibliographien und Atlassammlungen abgegrenzt werden. Weiterhin sind die gewonnenen Erkenntnisse für die Herausgeber neuer Atlaswerke und Atlasplattformen von großem Nutzen. Sie können in der Praxis als redaktionelle Grundlagen im Sinne eines Leitfadens zur erfolgreichen Produktion neuer, nutzergerechter Atlanten eingesetzt werden. Im beigefügten Atlasverzeichnis sind zudem 735 statistische Atlanten mit bibliographischen Angaben dargestellt.

Seit über 150 Jahren erscheinen in den statistischen Institutionen thematische Atlanten – bis heute über 2500 Werke. Als «Reiseführer» durch Gesellschaften erzählen sie spannende und vielfältige Geschichten über den Staat, die Menschen und deren Zusammenleben. Gerade im Kontext der Informationsgesellschaft nehmen solche Atlaswerke wieder sprunghaft zu und sprechen dabei ein außerordentlich breites Nutzerspektrum aus allen Berufskreisen an. Ziel der vorliegenden Dissertation war es, durch theoretische und empirische Methoden das Wesen, die geschichtliche Entwicklung und die prägenden Merkmale des «Statistischen Atlas» eingehend zu untersuchen und damit Forschungslücken in der Thematischen Kartographie, der Atlaskartographie und der Statistik zu schließen. Mit Hilfe einer neu entwickelten Definition sowie einer aktuellen Atlasklassifikation können statistische Atlanten eindeutig bestimmt und von verwandten Atlastypen – etwa dem National-, dem Regional- oder dem Planungsatlas – im Hinblick auf die korrekte Einordnung in Bibliographien und Atlassammlungen abgegrenzt werden. Weiterhin sind die gewonnenen Erkenntnisse für die Herausgeber neuer Atlaswerke und Atlasplattformen von großem Nutzen. Sie können in der Praxis als redaktionelle Grundlagen im Sinne eines Leitfadens zur erfolgreichen Produktion neuer, nutzergerechter Atlanten eingesetzt werden. Im beigefügten Atlasverzeichnis sind zudem 735 statistische Atlanten mit bibliographischen Angaben dargestellt.

Approved for public release; distribution is unlimited / The effects of radiation in GaAs solar cells has been extensively researched and the results of numerous investigation have yielded a considerable amount of information about the degradation in irradiated solar cells. This thesis establishes a novel method in which to use Silvaco's physically-based device simulator, ATLAS, to model the effects of radiation on solar cell output characteristics. A virtual model representing a single junction GaAs solar cell was created in ATLAS. The effects of radiation were modeled using carrier trapping statements representing the defects associated with various fluence levels of 1 MeV electron radiation which were characterized with Deep Level Transient Spectroscopy techniques. The resulting output characteristics of the virtual solar cell, illuminated with a simulated AM0 spectrum, were compared to published experimental measurements for GaAs solar cells of the same dimensions. The virtual solar cell demonstrated a good correlation between the measured and virtual solar cell output characteristics and accurate representation of the spectral response. Complete ATLAS and MATLAB codes are included in appendices. / Major, United States Marine Corps

The task of object detection and pose estimation has widely been done using template matching techniques. However, these algorithms are sensitive to outliers and occlusions, and have high latency due to their iterative nature. Recent research in computer vision and deep learning has shown great improvements in the robustness of these algorithms. However, one of the major drawbacks of these algorithms is that they are specific to the objects. Moreover, the estimation of pose depends significantly on their RGB image features. As these algorithms are trained on meticulously labeled large datasets for object's ground truth pose, it is difficult to re-train these for real-world applications. To overcome this problem, we propose a two-stage pipeline of convolutional neural networks which uses RGB images to localize objects in 2D space and depth images to estimate a 6DoF pose. Thus the pose estimation network learns only the geometric features of the object and is not biased by its color features. We evaluate the performance of this framework on LINEMOD dataset, which is widely used to benchmark object pose estimation frameworks. We found the results to be comparable with the state of the art algorithms using RGB-D images. Secondly, to show the transferability of the proposed pipeline, we implement this on ATLAS robot for a pick and place experiment. As the distribution of images in LINEMOD dataset and the images captured by the MultiSense sensor on ATLAS are different, we generate a synthetic dataset out of very few real-world images captured from the MultiSense sensor. We use this dataset to train just the object detection networks used in the ATLAS Robot experiment.

As the field of autonomous robots continue to advance, there is still a tremendous benefit to research human-supervised robot systems for fielding them in practical applications. The DRC inspired by the Fukushima nuclear power plant disaster has been a major research and development program for the past three years, to advance the field of human supervised control of robots for responding to natural and man-made disasters. The overall goal of the research presented in this thesis is to realise a new approach for semi-autonomous control of the Atlas humanoid robot under discrete commands from the human operator. A combination of autonomous and semi-autonomous perception and manipulation techniques to accomplish the task of detecting, opening and walking through a door are presented. The methods are validated in various different scenarios relevant to DRC door task.

This thesis presents the measurement and results of the Z/γ* → μ⁺μ⁻ Drell-Yan triple-differential cross-section, using 20.24 fb⁻¹ of ATLAS data recorded in 2012 at a centre-of-mass energy of √s = 8TeV. The triple-differential cross-section is measured as a function of dimuon invariant mass, m_μμ, dimuon rapidity, γ_μμ , and lepton decay angle in the Collins-Soper frame, cosθ*. These dimensions provide sensitivity to the parton composition of the proton through the parton density functions, PDFs, and the weak effective mixing angle, sin²θeff./W, via the forward-backward asymmetry, A_FB. The measurement is performed on and around the Z-boson's invariant mass peak, 46 < m_μμ < 200 GeV, in a kinematic ducial volume of muon transverse momentum, pT > 20 GeV, and muon pseudo-rapidity |η|≤2.4. The results are unfolded from the detector level to the Born, bare and dressed levels, where a precision of < 0:6% is reported in the central bins. The data is combined with an electron channel measurement resulting in a combined result with reduced total uncertainty. The combined result is shown to constrain PDF uncertainties and achieve the most constrained sin²θeff./W uncertainty yet reported at the LHC.

This thesis presents the results for two searches for new physics performed with the ATLAS experiment. The first, a search for the rare B-meson decay Bs → μμ and measurement of its branching ratio, uses 25 fb⁻¹ of √s = 7 and 8 TeV data recorded during 2011 and 2012. After observing a small number of these decays, a branching ratio of B(Bs → μμ) = (0.9⁺¹·¹₋₀.₈) x 10⁻⁹ is measured, assuming non-negative event yields. This is compatible with the Standard Model at the 2σ level. The second, a search for direct pair production of the supersymmetric top quark partner, is performed using 36.07 fb⁻¹ of √s = 13 TeV data recorded during 2015 and 2016. Final states with a high jet multiplicity, no leptons and large missing transverse momentum are selected to target these decays, with several signal regions designed to cover a wide range of particle masses. No excess is observed, with all signal regions being compatible with the Standard Model within 2σ. Limits are set on the stop mass, excluding up to mt̃1 = 940 GeV for values of mx̃⁰₁ below 160 GeV, assuming a 100% branching fraction to t̃1 → tX̃⁰₁ decays. In addition two reinterpretations of this data are presented, for a gluino-mediated stop production scenario and a direct dark matter production scenario. No excess is observed for either model, and limits are set on the mass of the relevant particles. Finally a viability study into using machine learning techniques to improve on existing SUSY search methods has been performed, with the initial results proving promising.

Three measurements of top-quark pair production cross sections in proton-proton collisions at sqrt(s) = 13 TeV using data collected by the ATLAS experiment are presented. The single-lepton final states are used, where one electron or muon, two b-jets and two other jets can be identified. The inclusive ttbar production cross section is measured to be sigma(ttbar) = 817 +/- 13 (stat.) +/- 103 (syst.) +/- 88 (lum.) pb, which is in good agreement with predictions and with other measurements. Absolute and relative differential cross sections of ttbar production are also measured, showing an overall good agreement with predictions, except for the top-quark transverse momentum distribution. As already reported in measurements at lower proton-proton collision energies, this distribution is shifted towards higher momenta in all predictions with respect to the observations. Total and differential fiducial cross sections of ttbar production in association with heavy-flavour jets are also presented. All tested models are found to agree with data within the uncertainties of these measurements.

This thesis presents a study of W±Z diboson production with the ATLAS experiment at the LHC. The measurements are made using 20.3fb⁻¹ of data collected during proton-proton collisions produced at a centre-of-mass energy of √s = 8 TeV. Final states with three leptons and missing transverse energy are considered. The first study of the polarisation of the W boson in such events is presented. This study provides a cross-section independent method by which to study anomalous gauge boson couplings. The estimated sensitivity of this measurement to anomalous gauge boson couplings will therefore also be presented. Also discussed, are measurements of the W±Z production cross-section and limits on anomalous gauge boson couplings. Finally, a study is presented which assess the impact of extending the inner-detector tracker to |η| = 4.0. This was considered for the ATLAS upgrade program. The effect of such an extension was studied for multiple final states, including the W±Z inclusive and VBS analyses as well as the WWW triboson analysis.