Now showing items 1-20 of 20

• #### A Top Quark Mass Measurement Using the R32 Stabilized Variable with the ATLAS Detector ﻿

(2012-08-31)
This thesis presents one of the first measurements of the top quark mass at the ATLAS experiment, one of the four large experiments located along the LHC. First discovered in 1995 at the Tevatron experiments CDF and D0, ...
• #### Analysis of Space Weather Impacts on the Terrestrial Ionosphere and Development and Testing of a Coronagraph for Space Weather Forecasts ﻿

(2020-07-22)
The ionosphere is a conductive layer of the Earth's atmosphere, characterised by the presence of free electrons. Through interaction with electromagnetic waves, it influences a wide spectrum of radio wave communications, ...
• #### Branching Fraction Measurement of B± → χc1π+π−K± and Search for a Narrow Resonance with the Belle Experiment ﻿

(2014-12-09)
The effective QCD colour potential can be derived by studying quarkonia through spectroscopy to determine their masses. In the charmonium spectrum, which is well understood and precisely measured below the DDbar production ...
• #### Characterisation, optimisation and performance studies of pixel vertex detector modules for the Belle II experiment ﻿

(2021-10-13)
The Standard Model of particle physics is very successful in describing the fundamental particles and their interactions. Still, some questions regarding the details and input parameters of the theory, as well as regarding ...
• #### Commissioning and first data taking experience with the Belle II pixel vertex detector ﻿

(2020-07-01)
The Belle II experiment at the SuperKEKB particle accelerator at KEK in Tsukuba (Japan) is the successor to the Belle experiment, which played a crucial role in the discovery of CP violation in the B-Meson system. The ...
• #### Development and validation of a model for the response of the Belle II vertex detector ﻿

(2014-11-06)
The future super flavour factory SuperKEKB with its detector system Belle II offers precision physics measurements to test the Standard Model or probe undiscovered phenomena. The physics goals of Belle II require a very ...
• #### Development of the readout for the IBL Upgrade Project of the ATLAS Pixel Detector ﻿

(2012-12-05)
The LHC luminosity is upgraded in several phases until 2022. The resulting higher occupancy degrades the detector performance of the current Pixel Detector. To provide a good performance during the LHC luminosity upgrade, ...
• #### High resolution scattering spectropolarimetry of the quiet solar photosphere ﻿

(2021-01-14)
In this thesis we investigate small-scale scattering polarization signals in quiet, internetwork (IN) regions of the lower solar atmosphere. Small-scale polarization signals are inherently hard to observe due to their ...
• #### Measurement of B-> pi pi l nu with Full Hadronic Reconstruction at Belle ﻿

(2018-12-03)
This thesis presents an analysis of the exclusive $B\to\pi^{+}\pi^{-}\ell\nu_{\ell}$ decay, where $\ell$ represents an electron or a muon. The analysis uses the complete $\Upsilon(4S)$ data sample collected by the Belle ...
• #### Measurement of Spin Correlations in Top/Anti-Top Events from pp Collisions at sqrt(s) = 7 TeV in the Lepton+Jets Final State with the ATLAS Detector ﻿

(2014-09-25)
The top quark decays before it hadronises. Before its spin state can be changed in a process of strong interaction, it is directly transferred to the top quark decay products. The top quark spin can be deduced by studying ...
• #### Measurement of the associated production of a vector boson (W, Z) and top quark pair in the opposite sign dilepton channel with pp collisions at &radic;s = 8 TeV with the ATLAS detector ﻿

(2015-01-08)
The heaviest known elementary particle predicted by the Standard Model (SM), the top quark, was discovered in 1995 by the CDF and D0 collaborations. The large top quark mass translates into a coupling to the Higgs boson ...
• #### Measurement of the branching fractions of the semileptonic decays B+ → ηlν and B+ → η′lν with signal-side only reconstruction at the Belle experiment ﻿

(2021-11-25)
This thesis presents a measurement of the branching fractions of the decays B+ → ηlν and B+ → η'lν. The entire data sample collected by the Belle experiment at the energy of the Υ(4S) resonance is used, which contains ...
• #### Measurement of the ttZ Production Cross Section in the Final State with Three Charged Leptons using 36.1 fb^-1 of pp Collisions at 13 TeV at the ATLAS Detector ﻿

(2018-02-14)
A measurement of the production cross section for a top quark pair in association with a Z boson (ttZ) is presented in this PhD thesis. Final states with exactly three charged leptons (electrons or muons) are used, taking ...
• #### Radiation length measurements with high-resolution telescopes ﻿

(2019-08-27)
The radiation length imaging method presented in this work can be used to conduct spatially resolved measurements of scattering angles of particles traversing a object under study. For the measurements a planar object is ...
• #### Search for B → π τ ν with hadronic tagging at Belle ﻿

(2015-11-24)
A search for the decay B → π τ ν is presented. The search is performed on the full Belle data set containing 772E6 B anti-B pairs, collected at the Y(4s) resonance with the Belle detector at the KEKB asymmetric energy e+e- ...
• #### Search for resonant Higgs boson pair production in the bb̄WW* decay channel in the boosted 1-lepton final state using the full Run 2 ATLAS dataset ﻿

(2022-05-03)
Despite the great success of the Standard Model of Particle Physics in explaining physics phenomena over a wide range of energy scales, many open questions remain and it is known that this model of nature is incomplete. ...
• #### Search for the Standard Model Higgs boson produced in association with tt and decaying into bb at 8 TeV with the ATLAS detector using the Matrix Element Method ﻿

(2015-11-02)
A search for the Standard Model Higgs boson produced in association with a pair of top quarks (ttH) is presented. The analysis uses 20.3 fb−1 of pp collision data at √s = 8 TeV, collected with the ATLAS detector at the ...
• #### Slender Ca II H fibrils observed by SUNRISE/SuFI ﻿

(2018-04-24)
This thesis is devoted to analyzing the morphological and oscillatory properties of slender \caiih{} fibrils (SCFs) in the lower solar chromosphere. The aim of this study is to deepen our understanding of the physical ...
• #### Strong magnetic fields and unusual flows in sunspots ﻿

(2023-02-06)
This thesis presents a study of sunspots, which are the most prominent features observed on the solar surface. Their structure is governed by the magnetic field. The umbra and penumbra of sunspots harbor different strengths ...
• #### Z →ττ Cross Section Measurement and ττ Mass Reconstruction with the ATLAS Detector at the LHC ﻿

(2012-11-14)
In this dissertation, the Z to tautau decay where one τ decays leptonically and the other one hadronically is presented. The process is studied with data collected from the ATLAS experiment in pp collisions at c-m-s = 7 TeV ...