| Title▼ | Belle II Number▼ | Tags | Submit date▼ | Downloads |
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An electromagnetic calorimeter cluster classifier as a beam background suppressant in B^0 → D^{∗+} l^− ν_l decays at the Belle II experiment.Public
The presence of beam background-related photons in the extra energy distributions of events reconstructed using Belle II data can make it difficult to accurately identify en- ergy missing from the detector that can be attributable to neutrinos or other hypothe- sized weakly interacting particles. By isolating samples of detector information relati… |
BELLE2-MTHESIS-2021-079 | - | 2020-11-11 |
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Real-Time Trigger and online Data Reduction based on Machine Learning Methods for Particle Detector TechnologyPublic
Modern particle accelerator experiments are producing immense amounts of data online during their operation. Storing the entire amount of generated data is quickly exceeding reasonable budgets for the data readout infrastructure. This problem is traditionally addressed by using a combination of trigger and data reduction mechanisms that are locate… |
BELLE2-PTHESIS-2021-015 | - | 2020-11-11 |
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Track selection optimisation for τ studies at Belle IIPublic
Being forbidden in the Standard Model, lepton flavour violating decays appears to be a good probe for searching physics beyond the standard model. In particular, the tau lepton, thanks to its high mass enables more lepton flavour violating decays: τ→lγ and τ→3l with l=e,μ. In addition the interest for τ decays is reinforced by several new physics… |
BELLE2-MTHESIS-2021-065 | - | 2020-11-11 |
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Belle II実験ARICH検出器アップグレードに向けた光検出器MPPCの研究Public
Belle II 実験は、SuperKEKB 加速器を用いて7GeV の電子ビームと4GeV の陽電子ビームを衝突させ、大量に生成されるB 中間子の崩壊過程をBelle II 測定器で精密に測定することで、標準模型を超える新物理を見つけることを目的とした実験である。Belle II 測定器に組み込まれているARICH 検出器は、輻射体シリカエアロゲルと光検出器HAPD (Hybrid Avalanche Photo-Detector) で構成されたリングイメージ型チェレンコフ検出器で、Belle II 測定器エンドキャップ部においてK/ 中間子の粒子識別を行っている。HAPD は高電圧(8kV) を印加した真空管内にピクセル化されたAPD(Avalanche Photo Diode) が内… |
BELLE2-MTHESIS-2021-029 | - | 2020-11-11 |
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R&D of the KEK Linac accelerator tuning using machine learningPublic
本研究では、高エネルギー加速器研究機構（KEK) における電子・陽電子入射器Linac の加速器運転調整システムの開発を行った。具体的には、機械学習を用いた加速管のRF 位相調整及び、ビーム位置補正のためのステアリング電磁石の調整のための基礎開発を行った。開発を行うために、Linac 加速器運転データを収集し、そのデータを用いて加速器運転パラメータの最適化手法を開発を行った。Linac加速器運転では、加速器を構成する数千点の機器パラメータを制御している。温度変化、振動等、環境の影響を受けて運転状況が変わるため、運転パラメータを常時調整している。運転調整の最適化、高速化を行い、入射効率を向上させるために、本研究では、機械学習を用いた運転パラメータ調整方法を開発した。機械学習は、複数のパラメー… |
BELLE2-MTHESIS-2021-023 | - | 2020-11-11 |
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Belle II 実験ARICH 検出器のための異常検知システムの開発Public
Belle II 実験は茨城県つくば市の高エネルギー加速器研究機構(KEK) で行われており,SuperKEKB 加速器で加速した電子-陽電子を衝突させることでB 中間子を大量に生成し,その崩壊過程に含まれる稀な事象を測定することで新物理の探索を行う. その測定を行うBelle II 測定器は, 複数の検出器によって構成されており, そのエンドキャップ部で新物理探索に感度がある崩壊モードに多く含まれる荷電K 中間子と荷電π 中間子の識別を行う装置がARICH(Aerogel Ring Imaging CHerenkov) 検出器である.高精度の新物理探索のためにはBelle II 測定器の長期安定運用が必要であり, 突発的な故障が生じた際は早急な対応が必要である. しかしARICH 検出器… |
BELLE2-MTHESIS-2021-028 | - | 2020-11-11 |
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Long term operation method of Belle II TOP detector from the viewpoint of the evaluation of photon detection performance (in Japanese)Public
Belle II実験は2018年にデータ取得を開始した重心系エネルギー10:58 GeVの電子陽電子衝突型Bファクトリー実験であり，2027年までに50 ab-1のデータを取得する予定である．この世界最高統計のデータを用い，標準理論の精密測定と新物理の探索を目指している．測定精度の向上には，B中間子の崩壊で生じるK/中間子を高い識別効率で同定することが重要である．そこで，Belle II実験では新型の粒子識別装置Time-Of-Propagation（TOP）カウンターを導入した．TOPカウンターは石英輻射体とその端面に取り付けた光検出器から成るリングイメージ型チェレンコフ検出器である．1つの荷電粒子あたりに検出されるチェレンコフ光子は20{40個程度であり，検出光子数が識別性能に影響する… |
BELLE2-MTHESIS-2021-010 | - | 2020-11-11 |
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Reconstruction of B0 → J/Psi K*0 decays at Belle II experiment in 2019 spring data and estimation of vertex resolution (written in Japanese) （日本語原題）Belle II 実験の2019年春期データにおけるB0 → J/Psi K*0崩壊の事象再構成と崩壊点位置分解能の評価Public
中性BメソンがJ/ψメソンとK*0メソンへ二体崩壊する過程について、モンテカルロシミュレーションにより当該事象を22%の効率で再構成できること、Bメソンの崩壊点を33ミクロンの位置分解能で再構成できることを示した。さらにBelle II実験が収集した2.6/fbのデータから49±7事象の信号を見出し、期待値と無矛盾であることを示した。 |
BELLE2-MTHESIS-2021-011 | - | 2020-11-11 |
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Development of monitoring system and performance evaluation for Belle II data acquisition systemPublic
The Belle II experiment is a B-factory experiment hosted by KEK in Tsukuba, Japan. Belle II experiment is the successor of the Belle experiment, which observed CP violation in the B-meson system. Belle II experiment observes decay products of the B-meson pairs created by the SuperKEKB accelerator by the Belle II detector to find new physics beyond… |
BELLE2-MTHESIS-2021-015 | - | 2020-11-11 |
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Search for dark matter with the high luminosity electron-positron collider (written in Japanese)Public
宇宙観測によれば宇宙にはダークマターが多量に存在するとされている。本研究では高輝度電子-陽電子衝突型加速器であるSUperKEKB/Belle IIを用いたダークマターの探索可能性について報告する。研究ではモデルに沿ったシミュレーション事象の生成、測定器シミュレーションおよび事象の解析を実験に沿った形で行い、1光子生成事象において、今後Belle II実験で探索が可能な領域を求めた。 |
BELLE2-MTHESIS-2021-016 | - | 2020-11-11 |
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In-depth characterization of diamond sensors for an update of the Belle II radiation monitorPublic
This thesis aims at deepening and improving the methods to characterise the response of diamond detectors in view of an upgrade of the radiation monitor of the Belle II particle- physics experiment. Three types of radiation are used: α and β particles, and, for the first time in this kind of characterisation, X-rays. I employed a novel method to c… |
BELLE2-MTHESIS-2020-008 | - | 2020-11-11 |
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Particle Identification using the Aerogel RICH Counter at the Belle II ExperimentPublic
We evaluated the particle identification performance of ARICH using D∗→D0(→Kπ)π decays with early beam collision data which correspond to an integrated luminosity of 5.15 ab−1. The result of overall performance of ARICH shows that K(π)efficiency is 93.5±0.6% (87.5±0.9%) with π(K) mis-identification probability of 10.9±0.9% (5.6±0.3%). We also eval… |
BELLE2-PTHESIS-2021-009 | - | 2020-11-11 |
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Particle Identification using the Aerogel RICH Counter at the Belle II ExperimentPublic
The Standard Model (SM) has been completed by observing the Higgs boson which is a last particle expected by the SM in 2012. However, the SM cannot explain non-zero neutrino mass, existence of dark matter and lack of gravity and so on. Therefore, we need the new physics (NP) beyond the SM to explain those things. The energy frontier experiment whi… |
BELLE2-PTHESIS-2021-008 | - | 2020-11-11 |
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Belle II and Synergies with the FCC-eePublic
This is a talk focusing on how the physics requirements influenced the technological choices made in the design of the Belle II detector and how this has played out in practice. |
BELLE2-TALK-CONF-2020-074 | - | 2020-11-10 |
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The Belle II experiment and synergies with FCC-eePublic
This is a talk focusing on how the physics requirements influenced the technological choices made in the design of the Belle II detector and how this has played out in practice. |
BELLE2-TALK-CONF-2020-072 | - | 2020-11-09 |
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Early results from Full Event Interpretation at Belle IIPublic
Full Event Interpretation is an algorithm for tag-side $B$ meson reconstruction at Belle II. The algorithm employs a hierarchical reconstruction of exclusive decay chains of $B$ mesons, with multivariate classifiers utilised to identify each unique sub-decay channel. Here, calibration factors are derived for hadronic tag-side $B$ decays by measuri… |
BELLE2-CONF-PROC-2020-021 | - | 2020-11-07 |
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Diversity and inclusion activities in Belle IIPublic
These proceedings accompany the Belle II talk in the diversity and inclusion parallel session delivered during ICHEP 2020. This marks the first external diversity and inclusion presentation by the Belle II Collaboration, in which we present the first Belle II collected data and self-reported statistics regarding diversity and inclusion. We also pr… |
BELLE2-CONF-PROC-2020-014 | - | 2020-11-05 |
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Low-momentum charged hadron identification using SVDPublic
We report a particle identification (PID) framework developed using energy loss information in the silicon-strip vertex detector (SVD) of Belle II for charged pions, kaons and protons using D∗+ -> D0[-> K pi+]pi+ and Lambda -> p pi- decay samples. The study is based on 6.1 fb−1 data recorded at the Y(4S) resonance by Belle II and the results are c… |
BELLE2-NOTE-PL-2020-028 | - | 2020-10-27 |
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Measurement of $ \gamma $ ($ \phi_3$) and first results on CP violation at Belle IIPublic
Flavor physics measurements at high luminosity $B$-factories offer a good probe for testing the Standard Model and looking for New Physics. With the first successful $e^+e^-$ collisions recorded in 2018, the Belle II experiment is accumulating its first physics data. The design instantaneous luminosity of the SuperKEKB accelerator is $6\times 10^{… |
BELLE2-CONF-PROC-2020-013 | - | 2020-10-26 |
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SuperKEKB/Belle II UpgradesPublic
I briefly review the status and plan for SuperKEKB and Belle II upgrades to reach an integrated luminosity of 50 ab^-1 within the decade. We call for collaboration and synergistic activities within the framework of the Snowmass high energy physics planning process. |
BELLE2-TALK-CONF-2020-068 | - | 2020-10-06 |
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