Theoretical studies to discover primordial black holes

2019 Fiscal Year Annual Research Report

• Project Area: Gravitational wave physics and astronomy: Genesis
• Project/Area Number: 18H04594
• Research Institution: High Energy Accelerator Research Organization
• Principal Investigator: 郡 和範 大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 准教授 (50565819)
• Project Period (FY): 2018-04-01 – 2020-03-31
• Keywords: 原始ブラックホール / PBH / インフレーション / 重力波 / 重力レンズ / CMB / ビッグバン元素合成 / 21cm線

Outline of Annual Research Achievements

PBHのレビュー論文 (Carr, et al, arXiv:2002.12778)を発表した。この論文により10の9乗グラムから10の17乗太陽質量までのPBHの存在量について観測からの上限値を報告した。Serpico, et al, arXiv:2002.10771において、PBHはその外にコールドダークマター(CDM)のハローを必然的に持ち、その系に宇宙のバリオンが宇宙論的に降着することを初めて指摘した。Planck衛星による宇宙マイクロ波背景放射の偏光観測を用いると、その降着円盤から放射される光を制限することになり、10の3乗倍から10の4乗倍の太陽質量の重さを持つPBHの存在量に、CDMの量の１億倍以下という厳しい制限が得られた。Matsubara, et al, arXiv:1909.04053において、宇宙初期にPBHのクラスタリングの問題を検討した。観測から示唆されるように、大スケールの非ガウス性が無視できるほど小さい時は、そのクラスタリングも無視できるほど小さいことが明快に示された。Inomata, et al,2019 (arXiv:1904.12879とarXiv:1904.12878)により、PBHを作る小スケールの宇宙初期の密度ゆらぎ(曲率ゆらぎ)が必然的に２次的な原始重力波を作り出すシナリオにおいて、宇宙初期の物質優勢から放射優勢への移行が、標準的な指数関数的な移行より速いメカニズムで進む場合は、２次的重力波が多く作られ、将来観測で検出可能であることを指摘した。Nakama, et al, arXiv:1905.04477により、PBHを生成する小スケールの曲率ゆらぎが存在する場合、同時にCDMによるUltra-Compact-Mini-Halo (UCMH)が作られることが示され、それを将来のパルサータイミング観測で検出できる可能性を指摘した。

Research Progress Status

令和元年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

令和元年度が最終年度であるため、記入しない。

Research Products

• [Int'l Joint Research] LAPTh/Montpellier U/IAP(フランス)
  • Country Name: FRANCE
  • Counterpart Institution: LAPTh/Montpellier U/IAP
• [Int'l Joint Research] Oxford U/Queen Mary U of London(英国)
  • Country Name: UNITED KINGDOM
  • Counterpart Institution: Oxford U/Queen Mary U of London
• [Int'l Joint Research] Aarhus U/Niels Bohr Institute(デンマーク)
  • Country Name: DENMARK
  • Counterpart Institution: Aarhus U/Niels Bohr Institute
• [Journal Article] Testing the Seesaw Mechanism and Leptogenesis with Gravitational Waves (2020)
  • Author(s): Dror Jeff A.、Hiramatsu Takashi、Kohri Kazunori、Murayama Hitoshi、White Graham
  • Journal Title: Physical Review Letters Volume: 124 Pages: 041804
  • DOI: 10.1103/PhysRevLett.124.041804
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Clustering of primordial black holes formed in a matter-dominated epoch (2019)
  • Author(s): Matsubara Takahiko、Terada Takahiro、Kohri Kazunori、Yokoyama Shuichiro
  • Journal Title: Physical Review D Volume: 100 Pages: 123544
  • DOI: 10.1103/PhysRevD.100.123544
  • Peer Reviewed / Open Access
• [Journal Article] MeV-scale reheating temperature and thermalization of oscillating neutrinos by radiative and hadronic decays of massive particles (2019)
  • Author(s): Hasegawa Takuya、Hiroshima Nagisa、Kohri Kazunori、Hansen Rasmus S.L.、Tram Thomas、Hannestad Steen
  • Journal Title: Journal of Cosmology and Astroparticle Physics Volume: 2019 Pages: 012～012
  • DOI: 10.1088/1475-7516/2019/12/012
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Dependence of accessible dark matter annihilation cross sections on the density profiles of dwarf spheroidal galaxies with the Cherenkov Telescope Array (2019)
  • Author(s): Hiroshima Nagisa、Hayashida Masaaki、Kohri Kazunori
  • Journal Title: Physical Review D Volume: 99 Pages: 123017
  • DOI: 10.1103/PhysRevD.99.123017
  • Peer Reviewed / Open Access
• [Journal Article] The CALorimetric Electron Telescope (CALET) on the International Space Station: Results from the First Two Years of Operation (2019)
  • Author(s): Asaoka Y、et al
  • Journal Title: EPJ Web of Conferences Volume: 208 Pages: 13001～13001
  • DOI: 10.1051/epjconf/201920813001
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Ultracompact minihalos associated with stellar-mass primordial black holes (2019)
  • Author(s): Nakama Tomohiro、Kohri Kazunori、Silk Joseph
  • Journal Title: Physical Review D Volume: 99 Pages: 123530
  • DOI: 10.1103/PhysRevD.99.123530
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Direct Measurement of the Cosmic-Ray Proton Spectrum from 50?GeV to 10?TeV with the Calorimetric Electron Telescope on the International Space Station (2019)
  • Author(s): Adriani O.、et al
  • Journal Title: Physical Review Letters Volume: 122 Pages: 181102
  • DOI: 10.1103/PhysRevLett.122.181102
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Enhancement of gravitational waves induced by scalar perturbations due to a sudden transition from an early matter era to the radiation era (2019)
  • Author(s): Inomata Keisuke、Kohri Kazunori、Nakama Tomohiro、Terada Takahiro
  • Journal Title: Physical Review D Volume: 100 Pages: 043532
  • DOI: 10.1103/PhysRevD.100.043532
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Gravitational waves induced by scalar perturbations during a gradual transition from an early matter era to the radiation era (2019)
  • Author(s): Inomata Keisuke、Kohri Kazunori、Nakama Tomohiro、Terada Takahiro
  • Journal Title: Journal of Cosmology and Astroparticle Physics Volume: 2019 Pages: 071～071
  • DOI: 10.1088/1475-7516/2019/10/071
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Prospective constraints on the primordial black hole abundance from the stochastic gravitational-wave backgrounds produced by coalescing events and curvature perturbations (2019)
  • Author(s): Wang Sai、Terada Takahiro、Kohri Kazunori
  • Journal Title: Physical Review D Volume: 99 Pages: 103531
  • DOI: 10.1103/PhysRevD.99.103531
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] The CALorimetric Electron Telescope (CALET) on the International Space Station: Results from the First Two Years On Orbit (2019)
  • Author(s): Asaoka Y、et al
  • Journal Title: Journal of Physics: Conference Series Volume: 1181 Pages: 012003～012003
  • DOI: 10.1088/1742-6596/1181/1/012003
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] Clustering of Primordial Black Holes produced in the early Matter Dominated Universe (2020)
  • Author(s): Kazunori Kohri
  • Organizer: The area workshop ``Gravitational wave physics and astronomy: Genesis''
• [Presentation] Positron and antiproton excess in nonstandard astrophysics/cosmology (2020)
  • Author(s): Kazunori Kohri
  • Organizer: CALET TIM meeting
  • Invited
• [Presentation] Formations and evolutions of PBHs in the matter-dominated Universe (2020)
  • Author(s): Kazunori Kohri
  • Organizer: Motpeller Cosmology seminar
  • Int'l Joint Research / Invited
• [Presentation] Formations and clusterings of primordial black hole dark matter formed in the matter dominated Universe (2020)
  • Author(s): Kazunori Kohri
  • Organizer: Kavli IPMU Cosmic Accelereation Workshop
  • Int'l Joint Research
• [Presentation] Dark matter / aLIGO events / OGLE events / a seed of SMBHs for primordial black holes in the radiation/matter dominated Universe (2020)
  • Author(s): Kazunori Kohri
  • Organizer: The international KEK-PH 2020 meeting
  • Int'l Joint Research
• [Presentation] Primordial Black Hole Cosmology (2019)
  • Author(s): Kazunori Kohri
  • Organizer: The 40th Anniversary Symposium of the US-Japan Science and Technology Cooperation Program in High Energy Physics
  • Int'l Joint Research / Invited
• [Presentation] Primordial Black Hole Cosmology (2019)
  • Author(s): Kazunori Kohri
  • Organizer: KMI seminar
  • Int'l Joint Research / Invited
• [Presentation] Primordial Black Hole Cosmology I (2019)
  • Author(s): Kazunori Kohri
  • Organizer: KIAS cosmology lecture
  • Int'l Joint Research / Invited
• [Presentation] Primordial Black Hole Cosmology II (2019)
  • Author(s): Kazunori Kohri
  • Organizer: KIAS cosmology lecture
  • Int'l Joint Research / Invited
• [Presentation] Primordial Black Hole Cosmology III (2019)
  • Author(s): Kazunori Kohri
  • Organizer: KIAS cosmology lecture
  • Int'l Joint Research / Invited
• [Presentation] ダークマターの謎に迫る 第1回 ダークマターとは何か？ (2019)
  • Author(s): 郡和範
  • Organizer: 朝日カルチャーセンター湘南
  • Invited
• [Presentation] 宇宙の「未発見」に挑む 第4回 ダークマター研究の最前線 (2019)
  • Author(s): 郡和範
  • Organizer: 朝日カルチャーセンター横浜
  • Invited
• [Presentation] Late-time entropy production and neutrino oscillation in the early Universe (2019)
  • Author(s): 郡和範
  • Organizer: 新学術領域研究「ニュートリノで拓く素粒子と宇宙」
• [Presentation] ダークマター候補: PBH、axion、WIMPの問題点 (2019)
  • Author(s): 郡和範
  • Organizer: ダークマターの懇談会2019
  • Invited
• [Presentation] 全国同時七夕講演会つくば 「最新の電波観測で宇宙のナゾをとく！」 [ お話その1 「ブラックホールは見えるか？」 (2019)
  • Author(s): 郡和範
  • Organizer: つくばエキスポセンター
  • Invited
• [Presentation] Neutrino oscillation in the early Universe (2019)
  • Author(s): 郡和範
  • Organizer: 国立天文台 科学研究部 COSNAP seminar
  • Invited
• [Presentation] つくばちびっ子博士2019「加速器ってなに？ 加速器科学の不思議を知ろう！」[ Bコース ``宇宙がむかし小さかった頃とブラックホールの意外な関係'' (2019)
  • Author(s): 郡和範
  • Organizer: KEKつくば
  • Invited
• [Presentation] DM annihilation <σv> and density profiles of dSphs with CTA (2019)
  • Author(s): Kazunori Kohri
  • Organizer: COSMO19
  • Invited
• [Presentation] Inflation models and future CMB B-mode observations (2019)
  • Author(s): Kazunori Kohri
  • Organizer: International conference TAUP2019
  • Int'l Joint Research / Invited
• [Presentation] 招待講演 ``はじめに'' (2019)
  • Author(s): 郡和範
  • Organizer: ２０１９年物理学会秋の分科会 シンポジウム「原始ブラックホール」
  • Invited
• [Presentation] 集中講義 ``素粒子的宇宙論入門'' (2019)
  • Author(s): 郡和範
  • Organizer: 京都大学理学部 物理第二教室 素粒子論研究室
  • Invited
• [Presentation] 教室談話会 ``Neutrino oscillation in the early Universe'' (2019)
  • Author(s): 郡和範
  • Organizer: 京都大学理学部 物理第二教室
  • Invited
• [Presentation] Primordial Black Holes (2019)
  • Author(s): Kazunori Kohri
  • Organizer: 京都大学理学部 物理第二教室 素粒子論研究室
  • Invited
• [Presentation] 消えた反物質を探せ 第1回 宇宙のはじまりと反物質 (2019)
  • Author(s): 郡和範
  • Organizer: 朝日カルチャーセンター新宿
  • Invited
• [Presentation] 元素はどのように生まれてきたのか？ 第1回 宇宙の始まりのビッグバン元素合成 (2019)
  • Author(s): 郡和範
  • Organizer: 朝日カルチャーセンター湘南
  • Invited
• [Presentation] Primordial Black Hole dark matter and future gamma-ray observations (2019)
  • Author(s): Kazunori Kohri
  • Organizer: CTA annual meeting The extreme Universe viewed in very-high-energy gamma-rays 2019
  • Int'l Joint Research
• [Presentation] Primordial Black Hole Cosmology in the Matter-Dominated Universe (2019)
  • Author(s): Kazunori Kohri
  • Organizer: APPC 2019 14TH ASIA-PACIFIC PHYSICS CONFERENCE
  • Int'l Joint Research / Invited
• [Presentation] Netrino oscillation in the early Universe (2019)
  • Author(s): Kazunori Kohri
  • Organizer: Particle Theory Seminar
  • Int'l Joint Research / Invited
• [Presentation] Formations and evolutions of PBHs in the matter-dominated Universe (2019)
  • Author(s): Kazunori Kohri
  • Organizer: Focus Week on Primordial Black Holes
  • Int'l Joint Research / Invited
• [Presentation] Dark matter models and observations of cosmic-ray electron and positron (2019)
  • Author(s): Kazunori Kohri
  • Organizer: CALET Staus Report
  • Invited
• [Presentation] Neutrino oscillation in the early Universe (2019)
  • Author(s): Kazunori Kohri
  • Organizer: LiteBIRD Staus Report
  • Int'l Joint Research
• [Presentation] Primordial Black Hole Cosmology (2019)
  • Author(s): Kazunori Kohri
  • Organizer: Academia Sinica seminar
  • Int'l Joint Research / Invited
• [Presentation] Axion-Like Particles with the Cosmicff IR and GeV-TeV Gamma-rayffobservations (2019)
  • Author(s): Kazunori Kohri
  • Organizer: LeCOSPA National Taiwan University
  • Int'l Joint Research / Invited
• [Presentation] Cosmological tests of Fundamental Physic (2019)
  • Author(s): Kazunori Kohri
  • Organizer: 2019 Joint Workshop of FKPPL and TYL/FJPPL
  • Int'l Joint Research
• [Book] 宇宙物理学ハンドブック (2020)
  • Author(s): 高原文郎、家正則、小玉英雄、高橋忠幸、他
  • Total Pages: 912
  • Publisher: 朝倉書店
  • ISBN: 978-4254131277
• [Book] 相対論と宇宙の事典 (2020)
  • Author(s): 安東正樹、白水徹也、石橋明浩、小林努、真貝寿明、早田次郎、谷口敬介, 他
  • Total Pages: 448
  • Publisher: 朝倉書店
  • ISBN: 978-4254131284
• [Remarks] 第25回日本物理学会論文賞
  • URL: https://www.jps.or.jp/activities/awards/ronbunsyo/ronbun25-2020.php
• [Remarks] プレスリリース (なぜ物質は完全消滅を免れたのか？ -重力波で探る物質の起源-)
  • URL: https://www2.kek.jp/ipns/ja/release/20200204/
• [Funded Workshop] KEK-Cosmo-2020 (2020)