Kazuki Kojima - Search Results - Belle II Document Server

guest :: login Belle II Document Server
		Search		Submit		Personalize Your alerts Your baskets Your searches		Help

Home > Search Results: Kazuki Kojima

Search:

Search Tips :: Advanced Search

Search collections:

Sort by:	Display results:	Output format:

1.	Recent Belle II results on semileptonic B decays and tests of lepton-flavor universality / Kazuki Kojima [BELLE2-TALK-DRAFT-2023-099] [BELLE2-TALK-CONF-2023-097] 15 minutes (12 minutes presentation + 3 minutes Q&A) https://www.leptonphoton2023.org/ 18 July 2023 / Lepton Photon 2023 Semileptonic $B$-meson decays allow for determining the magnitudes of the CKM matrix parameters $\|V_{cb}\|$ and $\|V_{ub}\|$, two fundamental parameters of the SM flavor sector and to probe the excess rate of semitauonic $B$ decays, which has been consistently above expectations in recent years. [...] Fulltext: PDF; Detailed record - Similar records
2.	Belle~II results related to $b \to c$ anomalies / Kazuki Kojima [BELLE2-TALK-CONF-2023-025] [BELLE2-CONF-PROC-2023-029] Contribution to the 2023 Electroweak session of the 57th Rencontres de Moriond 17 July 2023 We report two new measurements for tests of lepton flavor universality between electrons and muons using semileptonic $B$ decays with a data set of $189~\mathrm{fb}^{-1}$ collected at the Belle II experiment between 2019 and 2021. [...] Fulltext: PDF; Detailed record - Similar records
3.	Belle~II results related to $b \to c$ anomalies / Kazuki Kojima [BELLE2-TALK-CONF-2023-025] [BELLE2-TALK-DRAFT-2023-027] [BELLE2-PUB-DRAFT-2022-012] [BELLE2-PUB-DRAFT-2023-007] [BELLE2-CONF-DRAFT-2023-017] Page limit: 4 pages https://moriond.in2p3.fr/2023/EW/Contributions.html 10 July 2023 We report two novel measurements for tests of lepton flavor universality between electrons and muons using semileptonic $B$ decays with a data set of $189~\mathrm{fb}^{-1}$ collected at the Belle II experiment between 2019 and 2021. [...] Version1: PDF; Version2: PDF; Version3: PDF; Detailed record - Similar records
4.	Recent Belle II results related to flavor anomalies / Kazuki Kojima [BELLE2-NOTE-PH-2021-042] [BELLE2-NOTE-PH-2022-031] [BELLE2-TALK-DRAFT-2023-028] [BELLE2-TALK-CONF-2023-027] 15 minutes (13 minutes presentation + 2 minutes Q&A) https://indico.in2p3.fr/event/28466/ 29 March 2023 / International Conference on the Physics of the Two Infinities Persistent anomalies reported by various experiments in $b \rightarrow c$ and $b \rightarrow s\ell\ell$ transitions hint at possible violation of lepton-flavor universality. [...] Fulltext: PDF; Detailed record - Similar records
5.	Belle II results related to b→c anomalies / Kazuki Kojima [BELLE2-NOTE-PH-2021-042] [BELLE2-NOTE-PH-2022-031 ] [BELLE2-TALK-DRAFT-2023-027] [BELLE2-TALK-CONF-2023-025] 7 minutes (5 minutes presentation + 2 minutes Q&A) https://moriond.in2p3.fr/2023/EW/ 20 March 2023 / 57th Rencontres de Moriond 2023: Electroweak Interactions & Unified Theories Recent Belle II results of light-lepton flavor universality tests for b→c anomalies using semileptonic B decays are shown. [...] Fulltext: PDF; Detailed record - Similar records
6.	*$R(D^{})$ measurement using the hadronic tag algorithm with $189~\mathrm{fb}^{-1}$ data at the Belle~II experiment** / Kazuki Kojima ; Toru Iijima ; Qi-Dong Zhou ; Kodai Matsuoka ; et al [BELLE2-NOTE-PH-2022-032] [BELLE2-TALK-DRAFT-2023-035] [BELLE2-TALK-CONF-2023-024] 20 minutes (15 minutes presentation + 5 minutes Q&A); https://www.jps.or.jp/activities/meetings/past.php; https://kds.kek.jp/event/45609/ 22 March 2023 / The 2023 Spring Meeting of the Physical Society of Japan In the semileptonic decay of 𝐵 mesons, the global average of $R(D^{})$ measurement deviates from the Standard Model by more than $3\sigma$. [...] Slide in Japanese:* PDF; Detailed record - Similar records
7.	*$R(D^{})$ measurement using the hadronic tag algorithm at the Belle II experiment** / Kazuki Kojima ; Toru Iijima ; Qi-Dong Zhou ; Kodai Matsuoka ; et al [BELLE2-NOTE-PH-2022-032] [BELLE2-TALK-DRAFT-2022-137] [BELLE2-TALK-CONF-2022-111] 20 minutes (15 minutes presentation + 5 minutes Q&A) ; https://www.jps.or.jp/english/meetings-and-awards/autumn/autumn-meeting-index.html ; https://kds.kek.jp/event/43097/ 06 September 2022 / The 2022 Autumn Meeting of the Physical Society of Japan In the semileptonic decay of $B$ mesons, the global average of $R(D^{})$ measurement deviates from the Standard Model by $3.3\sigma$. [...] Belle II Note:* PDF; Slide in Japanese: PDF; Detailed record - Similar records
8.	Flavour Physics with Electroweak-Penguin and Semileptonic Decays at Belle II / Kazuki Kojima [BELLE2-TALK-DRAFT-2021-167] [BELLE2-TALK-CONF-2021-139] 20 minutes (17 minutes presentation + 3 minutes Q&A); https://indico.cern.ch/event/938795/contributions/4583181/ 30 November 2021 / Light Cone 2021: Physics of Hadrons on the Light Front In the recent years, several measurements of B-decays with flavor changing neutral currents, i.e. [...] Fulltext: PDF; Detailed record - Similar records
9.	The operation and performance of the TOP detector at the Belle II experiment / Kazuki Kojima [BELLE2-TALK-DRAFT-2021-095] [BELLE2-TALK-CONF-2021-128] 15 minutes (12 minutes presentation + 3 minutes Q&A) https://indico.desy.de/event/28202/contributions/105605/ 31 October 2021 / EPS-HEP2021 The SuperKEKB/Belle II experiment, the successor of the KEKB/Belle experiment at KEK, started the physics data taking with the full detector system in March 2019. [...] BELLE2-TALK-CONF-2021-128: PDF; BELLE2-TALK-CONF-2021-128 Slides: PDF; Detailed record - Similar records
10.	Long term operation method of Belle II TOP detector from the viewpoint of the evaluation of photon detection performance (in Japanese) / Kazuki Kojima [BELLE2-MTHESIS-2021-010] Presented on 10 02 2020 MSc 2020 Nagoya university / Nagoya 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．その光検出器には512台のMicrochannel Plate Photomultiplier Tube（MCP-PMT）が用いられている．MCP-PMTはBelle II実験の1:5 T磁場中でも動作し，高い時間分解能をもつ一方で，光電面寿命が一般的な光電子増倍管に比べて短く量子効率が積算出力電荷に依存して低下することが報告されている．特にBelle II実験は高頻度衝突や大電流ビームによって発生する物理過程や加速器に由来した高いバックグラウンド環境にあり，データ取得期間を通して高い信号弁別効率を保ちつつ十分な量子効率を維持するためには増幅率を適切に設定して出力電荷量を調整する必要がある．私は，TOPカウンターが微弱なチェレンコフ光から来る一光子を検出することに着目して，信号波高を変換することで増幅率を計算し，最新のランにおいて系統誤差1.5%の増幅率測定を実現した．これを用いて，衝突データから物理運転中の増幅率を測定するモニターを作成することで，連続した増幅率測定を可能にした．また，最新の運転期間において実際にモニターを使って物理運転中の増幅率と信号弁別効率を測定し，期間の開始時点からの変動を評価した．その結果，物理運転中において信号弁別効率は平均2%の変動であったが，増幅率は10%を超える変動が全MCP-PMTの33%で観測された．これにより，運転期間において印加電圧の再設定による実機調整の必要があることを明らかにした．さらに，物理運転中のヒットレート測定，検出光子数の測定と組み合わせることで，衝突データに基づく光子検出効率の変動の測定を実現した．本研究により，実験終了時まで量子効率および信号弁別効率を維持してMCP-PMTの運用を行い，TOPカウンターの光子検出能力を測定して長期的に運用する手法を確立した． Detailed record - Similar records

Interested in being notified about new results for this query?
Set up a personal email alert or subscribe to the RSS feed.

Haven't found what you were looking for? Try your search on other servers:
Kazuki Kojima in Amazon Kazuki Kojima in CERN EDMS Kazuki Kojima in CERN Indico Kazuki Kojima in CERN Intranet Kazuki Kojima in CiteSeer Kazuki Kojima in Google Books Kazuki Kojima in Google Scholar Kazuki Kojima in Google Web Kazuki Kojima in IEC	Kazuki Kojima in IHS Kazuki Kojima in INSPEC Kazuki Kojima in INSPIRE Kazuki Kojima in ISO Kazuki Kojima in KISS Books/Journals Kazuki Kojima in KISS Preprints Kazuki Kojima in NEBIS Kazuki Kojima in SLAC Library Catalog Kazuki Kojima in Scirus

Belle II Document Server :: :: :: ::
Powered by v1.1.2
Maintained by