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チェレンコフ光の精密再構成によるニュートリノ振動解析とCP対称性の破れの探索

Research Project

Project/Area Number 19J22440
Research Category

Grant-in-Aid for JSPS Fellows

Allocation TypeSingle-year Grants
Section国内
Review Section Basic Section 15020:Experimental studies related to particle-, nuclear-, cosmic ray and astro-physics
Research InstitutionTokyo Institute of Technology

Principal Investigator

BERNS LUKAS  東京工業大学, 理学院, 特別研究員(DC1)

Project Period (FY) 2019-04-25 – 2022-03-31
Project Status Completed (Fiscal Year 2021)
Budget Amount *help
¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2021: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2020: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2019: ¥1,000,000 (Direct Cost: ¥1,000,000)
Keywords水チェレンコフ / 素粒子 / ニュートリノ / 再帰反射材 / 事象再構成 / 機械学習 / 数値計算
Outline of Research at the Start

純水内で発生したチェレンコフ光をタンクの壁にしきつめられた光電子増倍管で捉え、光量と時間情報から粒子の物理量を再構成するという手法はカミオカンデの時代に確立し、現在まで引き続き用いられている。本研究ではまず、光電子増倍管の間に再帰反射材を配置し、反射光によってもう一つのリングを生成させるという筆者考案の新手法を実用化に向け開発する。またこれまでのリング再構成法において無視されてきた、荷電粒子の水中での微細な散乱に伴うチェレンコフ光の揺らぎを再構成に取り入れ、リング再構成の精度向上を目指す。これらによりニュートリノ振動等の物理をより正確に捉える他、将来実験に向けた検出器コスト削減への貢献を狙う。

Outline of Annual Research Achievements

今回開発した機械学習での再構成法を用い、水チェレンコフ検出器の7つデザインにて性能を比較した。それぞれのデザインは光電子増倍管の間に入れる反射材の種類が異なる。再帰反射材の場合、元々光量の少なさ故に当初の見積もりと比べ性能改善が限定的だったが、光学測定を元に去年度からさらに実装を改良した現実的な振る舞いのものでは、性能改善が見られなくなった。別構成である擬似再帰反射材に関しては現実的な振る舞いにおいてもある程度の性能改善が見込めるという結果になった。入射角とともに増える非理想的な反射が複雑さが原因と考えられ、擬似再帰反射材はこの寄与を抑えられる可能性の観点でも優れている。太陽ニュートリノなどの低エネルギーに関しても後輩の学生が修士論文研究で調べ、反射光量を増やすことが課題であるものの、位置やエネルギー再構成が改善することが確認できた。これらの結果の論文を今後発表予定である。

今年は大気・加速器ニュートリノの同時解析に力を入れ、振動確率計算、統計解析の各種改善、反応断面積モデル拡張とミスモデリング検出用の適合度検定の開発等行った。それぞれの実験データの整合性を検証したうえでレプトンCP破れ角と質量順序等に制限を与えた博士論文をまとめた。解析グループとしての結果発表に向け研究を続けている。また頻度主義的統計解析の高速化に関する二つ目の新手法を開発し、統計論文の投稿も準備している。

コロナの影響もあり、主にソフトウェア中心の研究となったが、再帰反射材の応用は課題の理解が深まり、揺らぎを考慮した再構成は機械学習での開発を通して過去最高の性能をシミュレーション上で実現。また統計解析の新技術の開発にも至り、最終的に水チェレンコフを用いた二つの実験の解析からCPの破れやニュートリノ振動のより精密な測定ができた。水チェレンコフ技術から発展してより広分野への貢献も含めた実りある研究ができた。

Research Progress Status

令和3年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

令和3年度が最終年度であるため、記入しない。

Report

(3 results)
  • 2021 Annual Research Report
  • 2020 Annual Research Report
  • 2019 Annual Research Report
  • Research Products

    (59 results)

All 2022 2021 2020 2019 Other

All Int'l Joint Research (10 results) Journal Article (22 results) (of which Int'l Joint Research: 18 results,  Peer Reviewed: 18 results,  Open Access: 22 results) Presentation (22 results) (of which Int'l Joint Research: 7 results,  Invited: 3 results) Remarks (5 results)

  • [Int'l Joint Research] TRIUMF(カナダ)

    • Related Report
      2021 Annual Research Report
  • [Int'l Joint Research] LPNHE Paris/CEA Saclay(フランス)

    • Related Report
      2021 Annual Research Report
  • [Int'l Joint Research] University of Rochester/Louisiana State University/University of Colorado Boulder(米国)

    • Related Report
      2021 Annual Research Report
  • [Int'l Joint Research] Eotvos Lorand University(ハンガリー)

    • Related Report
      2021 Annual Research Report
  • [Int'l Joint Research] Imperial College London(英国)

    • Related Report
      2021 Annual Research Report
  • [Int'l Joint Research] TRIUMF(カナダ)

    • Related Report
      2020 Annual Research Report
  • [Int'l Joint Research] Laboratoire Leprince-Ringuet/LPNHE Paris/CEA Saclay(フランス)

    • Related Report
      2020 Annual Research Report
  • [Int'l Joint Research] University of Colorado Boulder/Louisiana State University(米国)

    • Related Report
      2020 Annual Research Report
  • [Int'l Joint Research] Eotvos Lorand University(ハンガリー)

    • Related Report
      2020 Annual Research Report
  • [Int'l Joint Research] Imperial College London(英国)

    • Related Report
      2020 Annual Research Report
  • [Journal Article] Supernova Model Discrimination with Hyper-Kamiokande2021

    • Author(s)
      Y. Hayato, A. K. Ichikawa, M. Ishitsuka, Y. Itow, I. Shimizu et al. (Hyper-Kamiokande Collaboration)
    • Journal Title

      Astrophys. J.

      Volume: 916 Issue: 1 Pages: 15-15

    • DOI

      10.3847/1538-4357/abf7c4

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Recent Results from T2K2021

    • Author(s)
      Lukas Berns
    • Journal Title

      Proc. of the 55th Rencontres de Moriond, Electroweak

      Volume: EW Pages: 185-189

    • Related Report
      2021 Annual Research Report
    • Open Access
  • [Journal Article] First T2K measurement of transverse kinematic imbalance in the muon-neutrino charged-current single-π+ production channel containing at least one proton2021

    • Author(s)
      Abe K. et. al. (T2K collaboration)
    • Journal Title

      Physical Review D

      Volume: 103 Issue: 11 Pages: 1120091-27

    • DOI

      10.1103/physrevd.103.112009

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Improved constraints on neutrino mixing from the T2K experiment with 3.13×10^21 protons on target2021

    • Author(s)
      Abe K. et. al. (T2K collaboration)
    • Journal Title

      Physical Review D

      Volume: 103 Issue: 11 Pages: 1120081-62

    • DOI

      10.1103/physrevd.103.112008

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Event reconstruction performance with new retro-reflector based designs for water Cherenkov detectors2021

    • Author(s)
      Lukas Berns, S. Fujigami, M. Kuze, Y. Yamaguchi
    • Journal Title

      Journal of Physics: Conference Series

      Volume: 2156 Issue: 1 Pages: 012185-012185

    • DOI

      10.1088/1742-6596/2156/1/012185

    • Related Report
      2021 Annual Research Report
    • Open Access
  • [Journal Article] Measurements of \bar{\nu_\mu} and \bar{\nu_\mu} + \nu_\mu charged-current cross-sections without detected pions nor protons on water and hydrocarbon at mean antineutrino energy of 0.86GeV2021

    • Author(s)
      K.Abe, T.Ishida, Y.Oyama et al.
    • Journal Title

      Prog.Theor.Exp.Phys.

      Volume: 2021 Issue: 4 Pages: 1-28

    • DOI

      10.1093/ptep/ptab014

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] T2K measurements of muon neutrino and antineutrino disappearance using 3.13×10^21 protons on target2021

    • Author(s)
      K.Abe, T.Ishida, Y.Oyama et al.
    • Journal Title

      Phys.Rev.D

      Volume: 103 Issue: 1

    • DOI

      10.1103/physrevd.103.l011101

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] First measurement using a nuclear emulsion detector of the νμ charged-current cross section on iron around the 1 GeV energy region2021

    • Author(s)
      H. Oshima, T. Fukuda, Y. Hayato, S. Mikado, T. Nakaya, T. Nakadaira et al. (NINJA collaboration)
    • Journal Title

      PTEP (Prog Theor Exp Phys)

      Volume: 2021 Issue: 3

    • DOI

      10.1093/ptep/ptab027

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Research for Hadron Production Distribution to Reduce the Uncertainty on J-PARC Neutrino Beams2021

    • Author(s)
      Okada Ryo, Sakashita Ken, Berns Lukas, Koshio Yusuke
    • Journal Title

      JPS Conference Proceedings

      Volume: 33 Pages: 011130-011130

    • DOI

      10.7566/jpscp.33.011130

    • Related Report
      2020 Annual Research Report
    • Open Access
  • [Journal Article] First measurement of the charged current \bar{\nu_\mu} double differential cross section on a water target without pions in the final state2020

    • Author(s)
      K.Abe, T.Ishida, Y.Oyama et al.
    • Journal Title

      Phys.Rev.D

      Volume: 102 Issue: 1 Pages: 012007-012007

    • DOI

      10.1103/physrevd.102.012007

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] First combined measurement of the muon neutrino and antineutrino charged-current cross section without pions in the final state at T2K2020

    • Author(s)
      K.Abe, T.Ishida, Y.Oyama et al.
    • Journal Title

      Phys.Rev.D

      Volume: 101 Issue: 11 Pages: 112001-112001

    • DOI

      10.1103/physrevd.101.112001

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Measurement of the charged-current electron (anti-)neutrino inclusive cross-sections at the T2K off-axis near detector ND2802020

    • Author(s)
      K.Abe, T.Ishida, Y.Oyama et al.
    • Journal Title

      J.High Energ. Phys.

      Volume: 10 Issue: 10 Pages: 114-114

    • DOI

      10.1007/jhep10(2020)114

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Simultaneous measurement of the muon neutrino charged-current cross section on oxygen and carbon without pions in the final state at T2K2020

    • Author(s)
      T. Nakaya, Y. Hayato, T. Nakadaira et al. (T2K collaboration)
    • Journal Title

      Phys. Rev. D

      Volume: 101 Issue: 11 Pages: 112004-112004

    • DOI

      10.1103/physrevd.101.112004

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] First measurement of anti-νμ and νμ charged-current inclusive interactions on water using a nuclear emulsion detector2020

    • Author(s)
      A. Hiramoto, T. Fukuda, Y. Hayato, S. Mikado, T. Nakaya, T. Nakadaira et al. (NINJA collaboration)
    • Journal Title

      Phys. Rev. D

      Volume: 102 Issue: 7 Pages: 072006-072006

    • DOI

      10.1103/physrevd.102.072006

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Measurement of the muon neutrino charged-current single pi^+ production on hydrocarbon using the T2K off-axis near detector ND2802020

    • Author(s)
      K. Abe, T. Ishida, Y. Oyama et al.
    • Journal Title

      Physical Review D

      Volume: 101 Issue: 1 Pages: 012007-012007

    • DOI

      10.1103/physrevd.101.012007

    • Related Report
      2019 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Search for Electron Antineutrino Appearance in a Long-Baseline Muon Antineutrino Beam2020

    • Author(s)
      K. Abe et al. (The T2K Collaboration)
    • Journal Title

      Physical Review Letters

      Volume: 124

    • Related Report
      2019 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] New ideas for ring formation and reconstruction in water-Cherenkov detectors2020

    • Author(s)
      Berns Lukas
    • Journal Title

      Journal of Physics: Conference Series

      Volume: 1468 Issue: 1 Pages: 012165-012165

    • DOI

      10.1088/1742-6596/1468/1/012165

    • Related Report
      2019 Annual Research Report
    • Open Access
  • [Journal Article] Constraint on the Matter-Antimatter Symmetry-Violating Phase in Neutrino Oscillations2020

    • Author(s)
      Abe K et al. (T2K Collaboration)
    • Journal Title

      Nature

      Volume: 580 Issue: 7803 Pages: 339-339

    • DOI

      10.1038/s41586-020-2177-0

    • Related Report
      2019 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Measurement of the muon neutrino charged-current cross sections on water, hydrocarbon and iron, and their ratios, with the T2K on-axis detectors2019

    • Author(s)
      K. Abe, T. Ishida, Y. Oyama et al.
    • Journal Title

      Progress of Theoretical and Experimental Physics

      Volume: 2019 Issue: 9 Pages: 1-30

    • DOI

      10.1093/ptep/ptz070

    • Related Report
      2019 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Search for heavy neutrinos with the T2K near detector ND2802019

    • Author(s)
      Abe K et al. (T2K Collaboration)
    • Journal Title

      Physical Review D

      Volume: 100 Issue: 5 Pages: 052006-052006

    • DOI

      10.1103/physrevd.100.052006

    • Related Report
      2019 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Measurement of neutrino and antineutrino neutral-current quasielasticlike interactions on oxygen by detecting nuclear deexcitation gamma rays2019

    • Author(s)
      K. Abe, T. Ishida, Y. Oyama et al.
    • Journal Title

      Physical Review D

      Volume: 100 Issue: 11 Pages: 112009-112009

    • DOI

      10.1103/physrevd.100.112009

    • Related Report
      2019 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Search for neutral-current induced single photon production at the ND280 near detector in T2K2019

    • Author(s)
      K. Abe, T. Ishida, Y. Oyama et al.
    • Journal Title

      Journal of Physics G: Nuclear and Particle Physics

      Volume: 46 Issue: 8 Pages: 8-8

    • DOI

      10.1088/1361-6471/ab227d

    • Related Report
      2019 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Presentation] A new pion momentum systematic uncertainty and goodness-of-fit studies for joint analysis of atmospheric and accelerator neutrinos2022

    • Author(s)
      Lukas Berns, T2K Collaboration, Super-Kamiokande Collaboration
    • Organizer
      新学術領域「ニュートリノで拓く素粒子と宇宙」研究会
    • Related Report
      2021 Annual Research Report
  • [Presentation] 大気・加速器ニュートリノ同時解析に向けた π運動量系統誤差の導入と適合度検定2022

    • Author(s)
      Lukas Berns, Christophe Bronner, Mathieu Guigue, 久世正弘, Benjamin Quilain, Roger Wendell, Clarence Wret, Junjie Xia, Super-Kamiokande Collaboration, T2K Collaboration
    • Organizer
      日本物理学会 第77回年次大会
    • Related Report
      2021 Annual Research Report
  • [Presentation] T2K Experiment2022

    • Author(s)
      Lukas Berns, T2K collaboration
    • Organizer
      JPS 2022 Spring, Japan-Korea Joint Symposium for Experimental Particle Physics
    • Related Report
      2021 Annual Research Report
    • Invited
  • [Presentation] 再帰反射材を用いた水チェレンコフ検出器における低エネルギー事象の再構成手法2022

    • Author(s)
      藤上俊介,Lukas Berns,久世正弘,山口洋平
    • Organizer
      日本物理学会 第77回年次大会
    • Related Report
      2021 Annual Research Report
  • [Presentation] 大気・加速器ニュートリノ同時解析に向けた ニュートリノ振動確率計算法の開発2021

    • Author(s)
      Lukas Berns
    • Organizer
      新学術領域「ニュートリノで拓く素粒子と宇宙」オンライン若手研究会
    • Related Report
      2021 Annual Research Report
  • [Presentation] 大気・加速器ニュートリノ同時解析に向けた ニュートリノ振動確率計算法の開発2021

    • Author(s)
      Lukas Berns, Christophe Bronner, Mathieu Guigue, 久世正弘, Benjamin Quilain, Roger Wendell, Junjie Xia, Super-Kamiokande Collaboration, T2K Collaboration
    • Organizer
      日本物理学会 2021年秋季大会
    • Related Report
      2021 Annual Research Report
  • [Presentation] 再帰反射を用いた水チェレンコフ検出器における 高エネルギー事象再構成と性能改善の評価2021

    • Author(s)
      ベルンス・ルカス, 藤上俊介, 山口洋平, 久世正弘
    • Organizer
      日本物理学会 2021年秋季大会
    • Related Report
      2021 Annual Research Report
  • [Presentation] T2K neutrino beam flux prediction with improved MC tuning using latest NA61/SHINE hadron production data2021

    • Author(s)
      Lukas Berns, T2K Collaboration
    • Organizer
      28th International Workshop on Weak Interactions and Neutrinos (WIN 2021)
    • Related Report
      2021 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Event reconstruction performance with new retro-reflector based designs for water Cherenkov detectors2021

    • Author(s)
      Lukas Berns, Shunsuke Fujigami, Masahiro Kuze, Yohei Yamaguchi
    • Organizer
      17th International Conference on Topics in Astroparticle and Underground Physics (TAUP 2021)
    • Related Report
      2021 Annual Research Report
    • Int'l Joint Research
  • [Presentation] 最新の T2K 実験結果を用いたニュートリノ振動解析の詳細2021

    • Author(s)
      Lukas Berns, Christophe Bronner, Mathieu Guigue, Siva Prasad Kasetti, 久世正弘, Laura Munteanu, Benjamin Quilain, Mark Scott, and T2K Collaboration
    • Organizer
      日本物理学会 第 76 回年次大会
    • Related Report
      2020 Annual Research Report
  • [Presentation] Recent results from T2K2021

    • Author(s)
      Lukas Berns for T2K Collaboration
    • Organizer
      Rencontres de Moriond 2021: Electroweak Interactions & Unified Theories (Moriond EW 2021)
    • Related Report
      2020 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] ハイパーカミオカンデ建設予定地の方角に伴うニュートリノ・ビーム不定性の評価2020

    • Author(s)
      Lukas Berns, Megan Friend, Mark Hartz, 石塚正基, 久世正弘, 坂下健, and Hyper-Kamiokande Collaboration
    • Organizer
      日本物理学会 2020 年秋季大会
    • Related Report
      2020 Annual Research Report
  • [Presentation] Machine Learning based ring reconstruction for water Cherenkov detectors2020

    • Author(s)
      Lukas Berns, and Hyper Kamiokande Collaboration
    • Organizer
      新学術領域「ニュートリノで拓く素粒子と宇宙」研究会 2020
    • Related Report
      2020 Annual Research Report
  • [Presentation] Machine Learning based reconstruction for Hyper Kamiokande2020

    • Author(s)
      Lukas Berns for Hyper-Kamiokande Collaboration
    • Organizer
      Neutrino Physics and Machine Learning workshop
    • Related Report
      2020 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Latest results from T2K(COVID-19でキャンセル)2020

    • Author(s)
      Lukas Berns for T2K Collaboration
    • Organizer
      Rencontres de Moriond 2020: Electroweak Interactions & Unified Theories
    • Related Report
      2019 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Utilizing emission profile variations in water Cherenkov detectors2020

    • Author(s)
      Lukas Berns
    • Organizer
      26th 東京大学素粒子物理国際研究センターシンポジウム
    • Related Report
      2019 Annual Research Report
  • [Presentation] 再帰反射材やチェレンコフ光の揺らぎ情報を用いた水チェレンコフ検出器の性能改善の研究2020

    • Author(s)
      Lukas Berns, 久世正弘
    • Organizer
      日本物理学会 第75回年次大会
    • Related Report
      2019 Annual Research Report
  • [Presentation] Systematic Uncertainties of the T2K neutrino beam flux with improved MC tuning using NA61/SHINE replica target data2019

    • Author(s)
      Lukas Berns for T2K Collaboration
    • Organizer
      新学術領域「ニュートリノで拓く素粒子と宇宙」研究会2019
    • Related Report
      2019 Annual Research Report
  • [Presentation] New ideas for ring formation and reconstruction in water Cherenkov detectors2019

    • Author(s)
      Lukas Berns
    • Organizer
      XVI International Conference on Topics in Astroparticle and Underground Physics (TAUP 2019)
    • Related Report
      2019 Annual Research Report
    • Int'l Joint Research
  • [Presentation] T2Kニュートリノビームの系統誤差削減に向けたMCチューニング法の開発と整合性の評価2019

    • Author(s)
      Lukas Berns, Arturo Fiorentini, Megan Friend, Mark Hartz, 久世正弘, Tomislav Vladisavljevic, 坂下健, T2K Collaboration
    • Organizer
      日本物理学会 2019年秋季大会
    • Related Report
      2019 Annual Research Report
  • [Presentation] Neutrino flux prediction in the T2K experiment2019

    • Author(s)
      Lukas Berns for T2K Collaboration
    • Organizer
      11th International Workshop on Neutrino Beams and Instrumentation (NBI2019)
    • Related Report
      2019 Annual Research Report
    • Int'l Joint Research
  • [Presentation] A new CNN architecture for sub-manifolds embedded into higher dimensional space2019

    • Author(s)
      Lukas Berns
    • Organizer
      Deep Learning and Physics 2019
    • Related Report
      2019 Annual Research Report
  • [Remarks] NY Times, “Why the Big Bang Produced [...]”

    • URL

      https://www.nytimes.com/2020/04/15/science/physics-neutrino-antimatter-ichikawa-t2k.html

    • Related Report
      2020 Annual Research Report
  • [Remarks] BBC News, “Biggest cosmic mystery ‘step [...]”

    • URL

      https://www.bbc.com/news/science-environment-52297058

    • Related Report
      2020 Annual Research Report
  • [Remarks] Science, “Skewed neutrino behavior could [...]”

    • URL

      https://www.sciencemag.org/news/2020/04/skewed-neutrino-behavior-could-help-explain-matter-s-dominion-over-antimatter

    • Related Report
      2020 Annual Research Report
  • [Remarks] 東工大ニュース「ニュートリノの「CP位相角」を大きく制限」

    • URL

      https://www.titech.ac.jp/news/2020/046864.html

    • Related Report
      2020 Annual Research Report
  • [Remarks] 新学術領域「ニュートリノで拓く素粒子と宇宙」紹介パンフレット「若手研究者の育成と活躍」

    • URL

      https://www-he.scphys.kyoto-u.ac.jp/nucosmos/files/NC-pamph.pdf

    • Related Report
      2020 Annual Research Report

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Published: 2019-05-29   Modified: 2024-03-26  

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