| Title▼ | Belle II Number▼ | Tags | Submit date▼ | Downloads |
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| -Public | BELLE2-TALK-CONF-2022-089 | - | 2024-11-11 |
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Implementing the TabNet Deep Learning Algorithm for Selecting τ−→π−π−π+ντ Events from Belle II DataPublic
This thesis aims to compare TabNet, a Deep Learning (DL) algorithm for classi- fication of tabular data, to the established Boosted Decision Tree (BDT) used for event selection of the τ − → π−π−π+ντ decay. The goal is to see whether Tab- Net can outperform the established BDT. First the impact of hyperparameter values of TabNet were studied manual… |
BELLE2-UTHESIS-2024-002 | - | 2024-11-11 |
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Improving the Belle II Neural Track Trigger with Deep Neural NetworksPublic
In order to provide accurate measurements of Standard Model parameters and search for new physics at the precision frontier [1], the Belle II experiments aims to reach an instantaneous luminosity of 6 × 1035 cm−2s−1 [2]. An important tool for coping with the resulting high background levels is the Neural Track Trigger (NTT). This first level trigg… |
BELLE2-MTHESIS-2024-020 | - | 2024-11-11 |
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Upgrade of Belle II's Neural Network Trigger by Track Finding in Three-Dimensional Hough SpacePublic
The target luminosity of the Belle II experiment, located at the SuperKEKB electron-positron collider in Tsukuba, Japan, is 6x10^{35} cm^{-2}s^{-1}. For this world-record luminosity, high levels of beam background are expected. Thus, an efficient and robust trigger system at the hardware level, capable of selecting annihilation events from the int… |
BELLE2-MTHESIS-2024-018 | - | 2024-11-11 |
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Search for B+ -> K+ nu nubar at Belle II using Graph Neural NetworksPublic
This work presents the search for the decay of a charged B-meson into a charged kaon and a pair of neutrinos via graph-tagged analysis, which is an approach based on graph neural network, in Belle~II, which is operating at the asymmetric electron-positron collider SuperKEKB located at KEK, Tsukuba, Japan. B+ -> K+ nu nubar is a flavour changing … |
BELLE2-MTHESIS-2024-021 | - | 2024-11-11 |
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Search for lepton flavor universality violation in $\overline{B} \rightarrow D^{*}\tau^{-}\overline{\nu}_{\tau}$ decays using hadronic $B$ tagging at the Belle II experimentPublic
In the standard model of particle physics (SM), lepton flavor universality is an axiom that states that the coupling constants in the interaction between leptons and gauge particles are the same regardless of the lepton flavor $e$, $\mu$, or $\tau$. This universality has been demonstrated by various experiments. On the other hand, in the semi-lept… |
BELLE2-PTHESIS-2024-019 | - | 2024-11-11 |
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Test of light-lepton universality in tau decays with data from the Belle II experimentPublic
This thesis investigates light-lepton universality with electron-positron collision data from the Belle~II experiment at the SuperKEKB accelerator in Tsukuba, Japan. The data were recorded at a centre-of-mass energy of 10.58 GeV and are equivalent to an integrated luminosity of 362 fb$^{-1}$. Lepton universality is a property of the Standard Model… |
BELLE2-PTHESIS-2024-014 | - | 2024-11-11 |
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Tests of lepton universality in the rates of inclusive semileptonic B-meson decays at Belle IIPublic
This thesis presents two precision tests of lepton universality: the first measurement of the ratio of light-lepton branching fractions of inclusive semileptonic $B$-meson decays, $R(X_{e/mu}) = \mathcal{B}(B \to Xe\nu) / \mathcal{B}(B \to X\mu\nu)$, and the first successful measurement of inclusive $B \to X\tau\nu$ decays, measured in a ratio rel… |
BELLE2-PTHESIS-2024-017 | - | 2024-11-11 |
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Graph-Building and Input Feature Analysis for Edge Classification in the Central Drift Chamber at Belle IIPublic
This thesis investigates components of a Graph Neural Network (GNN)-based pipeline addressing challenges of current tracking algorithms at the Belle II experiment, such as highly displaced vertices and escalating beam backgrounds. The thesis examines input features for real-time pattern recognition algorithms, systematic graph-building in the Cent… |
BELLE2-MTHESIS-2024-019 | - | 2024-11-11 |
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Study of sPlot Background Subtraction for Particle Identification Efficiency Determination at Belle IIPublic
Particle identification is a central experimental challenge in the precise measurement of Standard Model parameters and in the search for new physics beyond the standard model at the Belle II experiment. This also includes an accurate knowledge of the imperfections in particle identification efficiencies. This efficiency is typically determined fr… |
BELLE2-UTHESIS-2024-003 | - | 2024-11-11 |
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Searches for dark sector particles at Belle and Belle IIPublic
Belle and Belle II experiments gathered around 1.5 ab$^{-1}$ of dataset near $\Upsilon(nS)$ resonances, which have constrained kinematics and low multiplicity suitable for dark sector searches. Both experiments have excellent sensitivity for dark sector searches in the few MeV - 10 GeV range. The latest dark sector searches performed by both colla… |
BELLE2-CONF-PROC-2024-028 | - | 2024-11-11 |
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Study of the B0->D*-l+vl decay at Belle II for a new measurement of the decay dynamics and |Vcb|Public
This is an experimental particle physics thesis that aims to study the exclusive semileptonic decay B0 → D∗−l+νl at Belle II for a new measurement of its decay dynamics and |Vcb|. Belle II is a particle physics experiment that focuses on weak-interaction processes of heavy quarks to search for indirect indications of non-standard-model physics. Th… |
BELLE2-UTHESIS-2024-004 | - | 2024-11-11 |
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Dalitz Plot Analysis of B0 → K+ π− π0 Decays at the Belle II ExperimentPublic
This thesis reports a determination of the branching fraction (B) and CP-violating charge asymmetry (ACP ) of the three-body decay B0 → K+ π− π0 at the Belle II experiment. In addition to the inclusive B and ACP , i.e. for B0 → K+ π− π0 decays, we measure B and ACP exclusively for individual two-body resonances appearing in the K+ π− π0 system. To… |
BELLE2-PTHESIS-2024-020 | - | 2024-11-11 |
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Study of monolithic CMOS pixel sensors in the Belle II experiment upgradePublic
Belle II is a particle physics experiment located at the KEK laboratory in Tsukuba (Japan). The detector is a general-purpose spectrometer to study electron-positron collisions produced by the SuperKEKB accelerator, a second generation flavor-factory which operates at the luminosity frontier, holding the world record of instantaneous luminosity wi… |
BELLE2-MTHESIS-2024-016 | - | 2024-11-11 |
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Measurement of the Branching Fraction of Charmless Semileptonic B Meson Decays and the Quark-Mixing Matrix Element Vub with the Belle II ExperimentPublic
This thesis presents the first inclusive untagged analysis of $B \to X_u \ell \nu$ decays using data from the Belle II experiment. Within the Standard Model theory of particle physics, these are weak decays of the $B$ meson to a hadron containing an up quark, $X_u$, a charged lepton (either an electron or a muon), $\ell$, and the corresponding lep… |
BELLE2-PTHESIS-2024-016 | - | 2024-11-11 |
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Study of the reconstruction efficiency of π0 mesons from decays of the lepton τ at the Belle II experimentPublic
This experimental particle-physics thesis explores a novel approach to the determination of the π0 meson reconstruction efficiency, whose uncertainty is a significant limitation in measurements sensitive to beyond Standard Model physics. I aim to determine the π0 reconstruction efficiency by comparing the rates of τ− → π− π^0 ντ with τ− → π− ντ de… |
BELLE2-MTHESIS-2024-022 | - | 2024-11-11 |
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Implementation, Operation and Monitoring of the Data Acquisition System of the Belle II Pixel Detector during Physics Data Taking in 2019 — 2022Public
This paper summarizes my contribution to the real-time data taking of the pixel detector of the Belle II experiment at the High Energy Accelerator Research Organization (KEK) in Tsukuba, Japan. The Belle II experiment is located at the SuperKEKB particle accelerator, where electrons and positrons collide with a center-of-mass energy of 7.4 GeV. In… |
BELLE2-PTHESIS-2024-021 | - | 2024-11-11 |
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Measurement of the properties of B0 → π0π0 decays at Belle IIPublic
This experimental particle-physics thesis reports measurements of the branching fraction and charge-parity (CP) violating decay-rate asymmetry of B0 → π0π0 decays reconstructed in electron-positron collisions with the Belle II detector. These quantities constrain parameters of potential processes not described by the Standard Model of particle phy… |
BELLE2-PTHESIS-2024-018 | - | 2024-11-11 |
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Measurement of |Vus| using hadronic τ decays at Belle IIPublic
This thesis presents a precise measurement of the CKM matrix element Vus using data collected at the Belle II experiment situated at the SuperKEKB electron- positron collider in Tsukuba, Japan. The measurement employs the ratio of branching fractions of tau lepton decays, denoted as RK/π, with both pion and kaon mesons in the final state, given by… |
BELLE2-PTHESIS-2024-015 | - | 2024-11-11 |
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A Study of the Decay $B\to\pi\ell\nu_\ell$ and Determination of the Standard Model parameter $|V_{\mathrm{ub}}|$ with the Belle II ExperimentPublic
Precision measurements of the magnitudes of the Cabibbo-Kobayashi-Maskawa (CKM)-matrix elements, which characterise the transitions between quarks of different flavours, are essential for testing the unitarity of the Unitarity Triangle (UT) described by the Standard Model. Of particular interest is the measurement of the magnitude of the matrix el… |
BELLE2-PTHESIS-2024-013 | - | 2024-11-11 |
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