2023-03-1210:54 Measurement of Lepton Mass Squared Moments of B→Xclν Decays with the Belle II Experiment and Determination of the CKM Matrix Element |Vcb| / Maximilian Welsch [BELLE2-PTHESIS-2023-004] Presented on 23 12 2022 PhD 2022 Physikalisches Institut / Bonn This thesis presents measurements of the first to fourth moments of the lepton mass squared q2=(pl + pν)2 distribution of B→Xclν decays for l=e,μ and with Xc denoting a hadronic system containing a charm quark [...] Fulltext: PDF; 2023-02-2500:56 Performance studies of Thin Fine-Pitch Silicon Vertex Detector for Belle II Vertex Detector upgrade / Zihan Wang ; Yutaka Ushiroda [BELLE2-MTHESIS-2023-005] Presented on 27 07 2022 MSc 2022 The University of Tokyo / Tokyo The Belle II experiment located at KEK, Tsukuba (Japan) precisely measures the Standard Model parameters analyzing various flavor physics processes to search for new physics beyond the Standard Model. [...] Fulltext: PDF; 2023-02-0115:47 Search for muonic dark force and performance studies of lepton identification at Belle II / Rajesh Kumar Maiti ; Gianluca Inguglia [BELLE2-PTHESIS-2023-003] Presented on 20 01 2023 PhD 2023 Institut of High Energy Physics / Vienna This thesis presents an advanced search strategy to find a new dark gauge boson 𝑍′ and performance studies of particle identification to assist the new physics searches, especially involving flavor-changing charge and neutral currents in semi- leptonic 𝐵 decays. [...] Fulltext: PDF; 2023-02-0103:02 Measurement of the time dependent CP Asymmetry of $B \to K^* \gamma$ decays in the Belle II experiment / Tristan Fillinger ; Jérôme Baudot [BELLE2-PTHESIS-2023-002] Presented on 30 09 2022 PhD 2022 Université de Strasbourg / Strasbourg The Standard Model of particle physics, which describes the fundamental particles and their interactions, is the most successful theory in the history of science. [...] Fulltext: PDF; 2023-01-3011:34 Study on first-level trigger of the Belle II experiment using upgraded silicon strip detector / Tomoyuki Shimasaki ; Takeo Higuchi [BELLE2-MTHESIS-2023-004] Presented on 27 01 2023 MSc 2023 The University of Tokyo / Tokyo In order to explore new physics beyond the Standard Model, the Belle II experiment plans to accumulate the integrated luminosity of 50 ab−1. [...] Fulltext: PDF; 2023-01-2616:36 Anomaly Detection in Searches for Inelastic Dark Matter with a Dark Higgs at Belle II / Jonas Eppelt ; Prof. Dr. Torben Ferber ; Prof. Dr. Günter Quast [BELLE2-MTHESIS-2023-003] Presented on 14 11 2022 MSc 2022 Insitut for Experimental Particle Physics / Karlsruhe In recent years a complementary search paradigm to classical searches has gained traction in the high energy physics community. [...] Fulltext: PDF; 2023-01-2607:31 Radiation tolerance studies of the double sided silicon strip sensor / Fumiaki Otani ; Takeo Higuchi [BELLE2-MTHESIS-2023-002] Presented on 27 01 2023 MSc 2023 The University of Tokyo / Tokyo, Japan The B meson decays can be studied precisely and compared with the standard model (SM) to search for new physics of elementary particles. [...] Fulltext: PDF; 2023-01-2512:42 Photon Reconstruction in the Belle II Calorimeter Using Graph Neural Networks / Florian Jochen Wemmer ; Prof. Dr. Torben Ferber ; Prof. Dr. Markus Klute [BELLE2-MTHESIS-2023-001] Presented on 11 11 2022 MSc 2022 Institute of Experimental Particle Physics (ETP) / Karlsruhe This thesis presents the implementation and performance of the GravNet algorithm for the photon energy reconstruction in the Belle II electromagnetic calorimeter [...] Fulltext: PDF; 2023-01-1915:10 Search for τ → ℓϕ lepton flavour violating decays and fake tracks rate measurement with e+ e− → τ+ τ− events at the Belle II experiment / Léonard Polat ; Justine Serrano [BELLE2-PTHESIS-2023-001] Presented on 14 12 2022 PhD 2022 CPPM / Marseille We report the search of lepton flavour violating τ → ℓϕ decays at the Belle II experiment, based on an integrated luminosity ∫ Ldt = 189.88 fb^(−1) of data collected from 2019 to 2021, at the Υ(4S) meson resonance energy s = √10.58 GeV. [...] Fulltext: PDF; 2022-11-2918:54 Optimization of long-lived neutral kaon detection and rejection at the Belle II experiment / Lucas Stötzer ; Prof. Dr. Jochen Dingfelder ; Dr. Peter Lewis [BELLE2-MTHESIS-2022-041] Presented on 21 11 2022 MSc 2022 Physikalisches Institut / Bonn We investigate an optimization of the reconstruction of neutral long living Kaons ($K_L^0$) at the Belle II experiment. [...] Fulltext: PDF;