| Title▼ | Belle II Number▼ | Tags | Submit date▼ | Downloads |
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Slow Pion Identification using the Pixel Detector of Belle IIPublic
Charged pions coming from D∗ decays are very useful to tag the flavor of neutral B mesons. At the Belle II experiment, these pions have low transversal momentum and therefore, a sizeable fraction does not reach all layers of the Silicon Strip Detector (SVD). As a consequence, the tracks of these ”slow” pions are not reconstructed. This will become… |
BELLE2-MTHESIS-2024-001 | - | 2023-11-11 |
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Measurements of $CP$ asymmetries in $D^0 \to \pi^+ \pi^- \pi^0$ decays in Dalitz plot regions at Belle IIPublic
We perform a search for charge-parity violation (CPV) in the density of events in a binned Dalitz plot of $D^*$-tagged $D^0 \to \pi^+ \pi^- \pi^0$ decays. The data used for this analysis is 362~$\text{fb}^{-1}$ of $\Upsilon(4S)$ data collected at Belle II from 2019--2022. We develop a novel binned Dalitz analysis method to determine local CPV; our… |
BELLE2-PTHESIS-2023-009 | - | 2023-11-11 |
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Search for the B+ to K+ nu anti-nu decay in the Belle II experimentPublic
This thesis describes the first search for the decay of a charged B meson into a charged kaon and a pair of neutrinos using a hadronic tagging method at the Belle II experiment, operating at the asymmetric electron-positron collider SuperKEKB located at KEK, Tsukuba, Japan. The B+ to K+ nu anti-nu decay operates, at the quark level, through a b to… |
BELLE2-PTHESIS-2023-019 | - | 2023-11-11 |
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Optimization of the PID algorithms at the Belle II ExperimentPublic
Particle identification in the Belle II experiment involves utilizing information from various sub-detectors to classify six different species of charged particles: electrons, muons, charged pions, charged kaons, protons, and deuterons. Previous studies have demonstrated that directly adding log-likelihoods from each detector for each hypothesis i… |
BELLE2-MTHESIS-2023-038 | - | 2023-11-11 |
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Time-Integrated Measurement of the Branching Fraction and Direct CP Asymmetry of B0 → KS0π0 Decay at Belle IIPublic
We report updated measurements of the branching ratio and the direct CP-violating asym- metry in B0 → KS0π0 decay at Belle II. The flavour information of the decay is obtained from the pair-produced neutral B partner Btag, and the direct CP asymmetry parame- ter is determined with the time-integrated method. We analyse the 2019-2022 Belle II data … |
BELLE2-MTHESIS-2024-009 | - | 2023-11-11 |
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Evaluation of the Radiation Hardness of MPPCs for Belle II ARICH Upgrade (In Japanese) BelleII実験ARICH検出器アップグレードに向けた光検出器MPPCの放射線耐性の評価Public
Evaluated the radiation hardness of MPPCs for Belle II ARICH Upgrade. |
BELLE2-MTHESIS-2024-004 | - | 2023-11-11 |
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Search for $\tau^-\to\mu^-\mu^+\mu^-$ lepton flavour violating decays and measurement of the SVD cluster position resolution at Belle II experimentPublic
Keywords: Particle physics; Search for New Physics; Lepton Flavour Violation; Tau lepton decays; Spatial resolution; Vertex detector Lepton flavour violating decays are considered one of the most effective ways to search for physics beyond the standard model, as they are not allowed in the Standard Model of particle physics. A number of new physic… |
BELLE2-PTHESIS-2024-001 | - | 2023-11-11 |
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The study of K0L Identification with ECL Information at Belle II experimentPublic
We can study K0L through K0L particle list reconstructed from ECL cluster or KLM cluster. Particle identification (PID) can help separate K0L from other particles, like γ, neutron, anti-neutron and other neutral particles. This thesis shows the establishment, method, performance and the comparison of K0L particle identification by using only ECL i… |
BELLE2-MTHESIS-2023-035 | - | 2023-11-11 |
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Phenomenological analysis and sensibility in Belle II of the $D_s^+ \to \pi^+ \mu^+\mu^-$ decay.Public
In this work we present a theoretical study and an experimental analysis of the $D_s^+ \to \pi^+ \mu^+\mu^-$ process in the Belle II experiment environment. This kind of process is interesting since it is used as reference in the search of suppressed or forbidden processes of the form $D_s^+ \to P^+ l^+ l^-$. In the theoretical part we explore the… |
BELLE2-PTHESIS-2023-013 | - | 2023-11-11 |
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Towards a Precision Measurement of Angular Observables in B decays at Belle IIPublic
The flavour changing neutral current b → sl+l− is considered to be one of the most promising particle transitions to search for new physics at the current point of time. It cannot occur directly in the Standard Model, but only through higher order processes, and is therefore highly suppressed. This suppression of the Standard Model amplitude makes… |
BELLE2-MTHESIS-2024-007 | - | 2023-11-11 |
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Measurement of time-dependent CP asymmetry in B0 -> KS0 π0 γ decays at the Belle II experimentPublic
We measure the time-dependent CP asymmetries in B0 -> KS0 π0 γ decay using (387.5 ± 5.8) × 10^6 BBbar pairs collected near the Υ(4S) resonance with SuperKEKB and Belle II from 2019 to 2022. For the measurement, we reconstruct one neutral B meson in the B0 -> KS0 π0 γ decay channel, identify the flavor of the accompanying B meson from its decay pr… |
BELLE2-PTHESIS-2024-007 | - | 2023-11-11 |
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The Alignment of Belle II ARICH Detector and its Influence on the PID Performance (In Japanese) BelleII実験におけるARICH検出器のアライメントと粒子識別性能への影響Public
We performed the alignment of Belle II ARICH detector, and studied its influence on the particle ID performance. |
BELLE2-MTHESIS-2024-005 | - | 2023-11-11 |
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Anomaly Detection using Isolation Forests in Searches for Inelastic Dark Matter with a Dark Higgs at Belle IIPublic
Anomaly detection as a method enables the study of new physical phenomena. This thesis studies the search for Dark Higgs signals given by the Inelastic Dark Matter with a Dark Higgs model. Using MC simulations and the Isolation Forests approach, collisions of electron-positron pairs at Belle II are analyzed to detect deviations in the event distri… |
BELLE2-UTHESIS-2023-001 | - | 2023-11-11 |
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A universal approach for particle identification at Belle II using neural networksPublic
The Belle II experiment aims to study the standard model (SM) of particle physics and to search for new physics (NP) beyond the standard model with unprecedented precision. This requires to accurately identify particles produced in these decays, necessitating the development of robust methods for particle identification (PID). This thesis presents… |
BELLE2-MTHESIS-2023-040 | - | 2023-11-11 |
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Measurement of the properties of B+ → ρ+ρ0 decays at Belle IIPublic
This experimental particle-physics thesis reports measurements of properties of B+ → ρ+ρ0 decays for the determination of the quark-mixing matrix angle α = arg(−(VtdV ∗)/(VudV ∗ )), a fundamental parameter of quark dynamics. The analysis tb ub uses the full data set of electron-positron collisions at the Υ(4S) resonance produced by the energy-asym… |
BELLE2-PTHESIS-2023-017 | - | 2023-11-11 |
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| Measurement of R(D*) with Inclusive B Meson Tagging at Belle IIPublic | BELLE2-MTHESIS-2024-014 | - | 2023-11-11 |
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Deep Generative Models for Ultra-High Granularity Particle Physics Detector Simulation: A Voyage From Emulation to ExtrapolationPublic
Simulating ultra-high-granularity detector responses in Particle Physics represents a critical yet computationally demanding task. This thesis aims to overcome this challenge for the Pixel Vertex Detector (PXD) at the Belle II experiment, which features over 7.5M pixel channels-the highest spatial resolution detector simulation dataset ever analys… |
BELLE2-PTHESIS-2024-006 | - | 2023-11-11 |
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Recovery of merged π0,s from ECL images of the Belle II detector using CNNPublic
This study aims to utilize a Convolutional Neural Network (CNN) to retrieve merged π0 mesons lost in the Belle II experiment, where they appear as individual photons. The issue arises when dealing with high momentum π0 mesons, i.e., beyond 2 GeV in the Belle II experiment, as the shower produced by both the π0 meson and gamma appear indistinguish-… |
BELLE2-MTHESIS-2024-003 | - | 2023-11-11 |
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Measurement of time-dependent CP asymmetries in B0 -> K+ K− KS0 decays with Dalitz-plot analysis at the Belle II experimentPublic
Abstract B0 -> φ KS0 decay process is dominated by b -> s sbar s penguin transition, which is sensitive to the contribution from new physics. B0 -> φ KS0 decay is particularly suited for the search of new physics due to the small theoretical uncertainty and suppressed tree diagram contribution within Standard Model. However, the measurement of CP … |
BELLE2-PTHESIS-2024-008 | - | 2023-11-11 |
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Measurement of the mass of the tau lepton in semi-invisible final states in the Belle II collaborationPublic
In this thesis, the mass of the tau lepton is determined by comparing three methods for decays with semi-invisible final states. The measurement was performed for the decay $\tau\pi\nu$ (signal). It is obtained that the best result was provided by the method $M_{min}$ for a mass of the tau lepton of m = $1777.06 \pm 0.44$ MeV. The measurement was … |
BELLE2-MTHESIS-2023-007 | - | 2023-11-11 |
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