New cosmology researched by primordial black holes

2021 Fiscal Year Annual Research Report

• Project Area: Gravitational wave physics and astronomy: Genesis
• Project/Area Number: 20H04750
• 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): 2020-04-01 – 2022-03-31
• Keywords: 原始ブラックホール / 宇宙論 / 一般相対性理論 / インフレーション / 量子ゆらぎ / ヒッグス / スタロビンスキーモデル

Outline of Annual Research Achievements

2022年度は、査読付き論文を７本発表し、外部での講演を14回行った。その中でも、論文1)において、原始ブラックホール連星の合体からのシグナルを空間的に相関させることで、天体ブラックホール連星の合体のシグナルと区別するアイデアを提案した。また、論文 3)では、原始ブラックホールの生成する新しいインフレーションモデルを提案している。原始ブラックホールは、ダークマターの有力な候補である。我々はこの論文において、Starobinsky-Higgsのmulti-fieldインフレーションモデルにおいて、tachyonic prehearingが起こり、小スケールのゆらぎが増幅され原始ブラックホールが作られることを指摘した。また、論文 6)において、インフレーション直後に現れたと期待されるインフラトンの振動による物質優勢期において、原始ブラックホールが作られる機構に新しいプロセスを発見した。原始ブラックホールを作ると期待される密度ゆらぎの中でもsmall scaleの密度ゆらぎが、先にvirializationすることにより原始ブラックホールの生成を抑制してしまうのである。この論文では、それを避けるための条件を詳しく調べた。特に、この論文 6)の成果は、私がライフワークとして行ってきてきた宇宙初期の物質優勢期における原始ブラックホールの形成条件の総まとめとなっている。これらのことは、今回の「原始ブラックホールで探る新しい宇宙論」のプロジェクト研究における極めてオリジナリティーの高い成果であり、この分野の世界の研究を主導するものである。

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。

Research Products

• [Int'l Joint Research] Yonsei U/IBS(韓国)
  • Country Name: KOREA (REP. OF KOREA)
  • Counterpart Institution: Yonsei U/IBS
• [Int'l Joint Research] CAS, Beijing(中国)
  • Country Name: CHINA
  • Counterpart Institution: CAS, Beijing
• [Int'l Joint Research] MPA(ドイツ)
  • Country Name: GERMANY
  • Counterpart Institution: MPA
• [Journal Article] Formation of hot spots around small primordial black holes (2023)
  • Author(s): He Minxi、Kohri Kazunori、Mukaida Kyohei、Yamada Masaki
  • Journal Title: Journal of Cosmology and Astroparticle Physics Volume: 2023 Pages: 027～027
  • DOI: 10.1088/1475-7516/2023/01/027
  • Peer Reviewed
• [Journal Article] Threshold of primordial black hole formation againstvelocity dispersion in matter-dominated era (2023)
  • Author(s): Harada Tomohiro、Kohri Kazunori、Sasaki Misao、Terada Takahiro、Yoo Chul-Moon
  • Journal Title: Journal of Cosmology and Astroparticle Physics Volume: 2023 Pages: 038～038
  • DOI: 10.1088/1475-7516/2023/02/038
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Search for Gamma-Ray Spectral Lines from Dark Matter Annihilation up to 100 TeV toward the Galactic Center with MAGIC (2023)
  • Author(s): Abe H.、et al, the MAGIC Collaboration, and N. Hiroshima and K. Kohri
  • Journal Title: Physical Review Letters Volume: 130 Pages: Phys. Rev. Lett
  • DOI: 10.1103/PhysRevLett.130.061002
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Probing primordial black holes with anisotropies in stochastic gravitational-wave background (2022)
  • Author(s): Wang Sai、Vardanyan Valeri、Kohri Kazunori
  • Journal Title: Physical Review D Volume: 106 Pages: 123511
  • DOI: 10.1103/PhysRevD.106.123511
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Cosmological 21-cm line observations to test scenarios of super-Eddington accretion on to black holes being seeds of high-redshifted supermassive black holes (2022)
  • Author(s): Kohri Kazunori、Sekiguchi Toyokazu、Wang Sai
  • Journal Title: Physical Review D Volume: 106 Pages: 43539
  • DOI: 10.1103/PhysRevD.106.043539
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] The inflaton that could: primordial black holes and second order gravitational waves from tachyonic instability induced in Higgs-R^2 inflation (2022)
  • Author(s): Cheong Dhong Yeon、Kohri Kazunori、Park Seong Chan
  • Journal Title: Journal of Cosmology and Astroparticle Physics Volume: 2022 Pages: 015～015
  • DOI: 10.1088/1475-7516/2022/10/015
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] A possible solution to the helium anomaly of EMPRESS VIII by cuscuton gravity theory (2022)
  • Author(s): Kohri Kazunori、Maeda Kei-ichi
  • Journal Title: Progress of Theoretical and Experimental Physics Volume: 2022 Pages: 910
  • DOI: 10.1093/ptep/ptac114
  • Peer Reviewed
• [Presentation] Gamma-ray Emission from Primordial Black Holes (2023)
  • Author(s): Kazunori Kohri
  • Organizer: The extreme Universe viewed in very-high-energy gamma rays 2022
  • Int'l Joint Research / Invited
• [Presentation] Cosmological 21cm line observations to test scenarios of super-Eddington accretion on to seed BHs of high-z SMBHs (2022)
  • Author(s): Kazunori Kohri
  • Organizer: The hybrid-style symposium on Gravitational wave physics and astronomy: Genesis
  • Int'l Joint Research
• [Presentation] Primordial black holes and secondary gravitational waves in the inflationary Universe (2022)
  • Author(s): Kazunori Kohri
  • Organizer: Extreme Universe Online, Kick-Off Meeting of Publicly Offered Research Groups
  • Int'l Joint Research
• [Presentation] The sterile-active neutrino oscillation and lepto- and/or baryogenesis in the early Universe (2022)
  • Author(s): Kazunori Kohri
  • Organizer: Exploration of Particle Physics and Cosmology with Neutrino
  • Int'l Joint Research
• [Presentation] Cosmological 21cm line observations to test scenarios of super-Eddington accretion on to seed BHs of high-z SMBHs (2022)
  • Author(s): Kazunori Kohri
  • Organizer: 初代星・初代銀河研究会 2022
  • Invited
• [Presentation] Theoretical research on methods to measure quantum natures of evaporating primordial black holes by using future observations (2022)
  • Author(s): Kazunori Kohri
  • Organizer: The 2nd Annual Meeting on Extreme Universe
  • Int'l Joint Research
• [Presentation] Primordial black holes and induced gravitational waves in inflationery models (2022)
  • Author(s): Kazunori Kohri
  • Organizer: 東京女子大学 素粒子論セミナー
  • Invited
• [Presentation] MeV γ-ray/CMB: New eyes with which to see quantum nature of Primordial Black Holes (2022)
  • Author(s): Kazunori Kohri
  • Organizer: QUP Project Q workshop
  • Int'l Joint Research / Invited
• [Presentation] Cosmological 21cm line observations to test scenarios of super-Eddington accretion on to seed BHs of high-z SMBH (2022)
  • Author(s): Kazunori Kohri
  • Organizer: 筑波大学 天体形成研究会 2022_
  • Int'l Joint Research / Invited
• [Presentation] Testing the early matter-dominated epoch in the early Universe in terms of BBN, CMB, PBH, DM and GWs (2022)
  • Author(s): Kazunori Kohri
  • Organizer: The Future is Illuminating
  • Int'l Joint Research / Invited
• [Presentation] 1) Anisotropies of GWs from merging PBHs, and 2)PBHs and GWs from tachyonic instability induced in Higgs-R^2 inflation (2022)
  • Author(s): Kazunori Kohri
  • Organizer: Non-linear Gravitational wave
  • Int'l Joint Research / Invited
• [Presentation] Testing primordial black-hole dark matter by gamma-ray, gravitational wave, and strong lensing of fast radio bursts (2022)
  • Author(s): Kazunori Kohri
  • Organizer: CosPA 2022
  • Int'l Joint Research / Invited
• [Presentation] Recent topics of PBHs (2022)
  • Author(s): Kazunori Kohri
  • Organizer: Dynamics of primordial black hole formation
  • Invited
• [Book] 台灣東販 (2022)
  • Author(s): Kazunori Kohri
  • Total Pages: 269
  • Publisher: 大人的宇宙學教室：透過微中子與重力波解密宇宙起源
  • ISBN: 9786263292758
• [Remarks] 巨大望遠鏡で狙う暗黒物質からの”光”;天の川銀河中心観測で解き明かす宇宙暗黒物質の起源と正体
  • URL: https://www.icrr.u-tokyo.ac.jp/news/13105/
• [Funded Workshop] The KEK-PH + KEK-Cosmo + QUP joint lectures and workshops 2023 on "Hubble Tension 2023" (21st, Feb. - 22nd Feb. 2023) (2023)