Study of nuclear matrix elements of neutrinoless double-beta decay by parity-transfer reactions

• Project/Area Number: 16K17683
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: The University of Tokyo
• Principal Investigator: Dozono Masanori 東京大学, 大学院理学系研究科(理学部), 特任助教 (60616259)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000); Fiscal Year 2019: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000); Fiscal Year 2018: ¥390,000 (Direct Cost: ¥300,000、Indirect Cost: ¥90,000); Fiscal Year 2017: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2016: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
• Keywords: スピン双極子遷移 / 二重ベータ崩壊 / ニュートリノレス二重ベータ崩壊 / 重イオン荷電交換反応

Outline of Final Research Achievements

A new method, parity-transfer reaction, has been established to study spin-dipole 2- excitations in nuclei, which is important for calibrating nuclear matrix elements of neutrinoless double-beta decays. The first proof-of-principle experiment has demonstrated that the parity-transfer reaction is quite an efficient probe to 2- states in nuclei. Studies of spin-dipole 2- excitations in double-beta decay nuclei are now feasible with the experimental method established in this work.

Academic Significance and Societal Importance of the Research Achievements

本研究で確立した手法により、二重ベータ崩壊核のスピン双極子2-遷移の実態が明らかになれば、核行列要素の理論計算に対して実験的に大きな指標を与え、理論モデルの精緻化を促すと予想される。核行列要素の予言精度向上は二重ベータ崩壊寿命から導出されるニュートリノ質量の精度向上に直結するため、本研究はニュートリノの性質解明に対して大きな意義を持つ。また、本研究で開発した測定手法は、放射性廃棄物の核変換に必要な核反応の基礎データの取得実験にも用いられるなど、社会的な貢献もみせている。

Research Products

• [Journal Article] OEDO, the energy-degrading beamline at RI Beam Factory (2019)
  • Author(s): Michimasa Shin'ichiro, Hwang Jongwon, Yamada Kazunari, Shimoura Susumu, et al.
  • Journal Title: Progress of Theoretical and Experimental Physics Volume: 2019 Issue: 4
  • DOI: 10.1093/ptep/ptz007
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Angle-tunable wedge degrader for an energy-degrading RI beamline (2019)
  • Author(s): Hwang Jongwon, Michimasa Shin'ichiro, Shimoura Susumu, et al.
  • Journal Title: Progress of Theoretical and Experimental Physics Volume: 2019 Issue: 4
  • DOI: 10.1093/ptep/ptz028
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Proton- and deuteron-induced reactions on 107Pd at 20-30 MeV/u (2019)
  • Author(s): M. Dozono et al.
  • Journal Title: CNS Annual Report 2017 Volume: 97 Pages: 3-4
  • Peer Reviewed / Open Access
• [Journal Article] Proton- and deuteron-induced reactions on 107Pd and 93Zr at 20-30 MeV/nucleon (2018)
  • Author(s): M. Dozono et al.
  • Journal Title: RIKEN Accelerator Progress Report 2017 Volume: 51 Pages: 99-99
  • Peer Reviewed / Open Access
• [Journal Article] Development of an active stopper for isomer tagging (2018)
  • Author(s): M. Dozono et al.
  • Journal Title: CNS Annual Report Volume: 96 Pages: 61-62
  • NAID: 130008157255
  • Peer Reviewed / Open Access
• [Journal Article] Parity-transfer (16O,16F(0-)) reaction to study spin-dipole 0- states (2017)
  • Author(s): M. Dozono et al.
  • Journal Title: RIKEN Accelerator Progress Report 2016 Volume: 50 Pages: 57-57
  • Peer Reviewed / Open Access
• [Journal Article] Separated flow operation of the SHARAQ spectrometer (2017)
  • Author(s): M. Dozono et al.
  • Journal Title: RIKEN Accelerator Progress Report 2016 Volume: 50 Pages: 204-204
  • Peer Reviewed / Open Access
• [Presentation] アイソマー同定のためのアクティブストッパーの開発 (2020)
  • Author(s): 堂園昌伯
  • Organizer: 日本物理学会第75回年次大会
• [Presentation] Proton-induced reactions on 107Pd at around 30MeV/nucleon: First result using slowed-down RI beams at OEDO (2019)
  • Author(s): Masanori Dozono
  • Organizer: International Nuclear Physics Conference 2019
  • Int'l Joint Research
• [Presentation] 低速RIビームを用いた107Pdの陽子・重陽子誘起反応測定 (2019)
  • Author(s): 堂園昌伯
  • Organizer: 日本物理学会第74回年次大会
• [Presentation] Nuclear reaction study for long-lived fission products in nuclear waste: Proton- and deuteron-induced reactions on 107Pd and 93Zr at 20-30 MeV/u (2018)
  • Author(s): M. Dozono
  • Organizer: 5th Joint Meeting of the APS Division of Nuclear Physics and the Physical Society of Japan
  • Int'l Joint Research
• [Presentation] アイソマー同定のための新しいガンマ線手法の開発 (2017)
  • Author(s): 堂園昌伯
  • Organizer: 平成２８年度HIMAC共同利用研究成果発表会
• [Presentation] The parity-transfer (16O,16F) reaction for studies of spin-dipole excitations in nuclei (2016)
  • Author(s): Masanori Dozono
  • Organizer: International Workshop on Neutrino Nuclear Responses for Double Beta Decays and Astro-Neutrino Interactions (NNR16)
  • Place of Presentation: 大阪大学 (大阪府吹田市)
  • Year and Date: 2016-09-29
• [Presentation] 不安定核で切り拓くスピン・アイソスピン応答研究 (2016)
  • Author(s): 堂園昌伯
  • Organizer: 日本物理学会2016年秋季大会
  • Place of Presentation: 宮崎大学 (宮崎県宮崎市)
  • Year and Date: 2016-09-21
• [Presentation] SHARAQスペクトロメータにおける陽子-重イオン同時測定モードの開発 (2016)
  • Author(s): 堂園昌伯
  • Organizer: 日本物理学会2016年秋季大会
  • Place of Presentation: 宮崎大学 (宮崎県宮崎市)
  • Year and Date: 2016-09-21
• [Presentation] Parity-transfer (16O,16F(0-)) reaction for study of spin-dipole 0- mode (2016)
  • Author(s): Masanori Dozono
  • Organizer: The 9th international Conference on Direct Reactions with Exotic Beams (DREB) 2016
  • Place of Presentation: Halifax (Canada)
  • Year and Date: 2016-07-11
  • Int'l Joint Research
• [Presentation] Separated flow operation of the SHARAQ spectrometer for in-flight proton-decay experiments (2016)
  • Author(s): Masanori Dozono
  • Organizer: International Symposium on Modern Technique and its Outlook in Heavy Ion Science (MOTO16)
  • Place of Presentation: 立教大学 (東京都豊島区)
  • Year and Date: 2016-06-26