Study of gamma-rays from proton-oxygen interaction for neutrino-oxygen reaction experiment

2014 Fiscal Year Final Research Report

• Project/Area Number: 23340073
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: Okayama University
• Principal Investigator: SAKUDA MAKOTO 岡山大学, 自然科学研究科, 教授 (40178596)
• Co-Investigator(Kenkyū-buntansha): TAMII Atsushi 大阪大学, 核物理研究センター, 准教授 (20302804) ; SUZUKI Tomokazu 大阪大学, 核物理研究センター, 准教授 (80506395)
• Co-Investigator(Renkei-kenkyūsha): NAKAHATA Masayuki 東京大学, 宇宙線研究所, 教授 (70192672) ; TORU Sato 大阪大学, 理学研究科, 准教授 (10135650) ; YOSOI Masaru 大阪大学, 核物理研究センター, 教授 (80183996)
• Project Period (FY): 2011-04-01 – 2015-03-31
• Keywords: ニュートリノ酸素反応 / 酸素炭素巨大共鳴

Outline of Final Research Achievements

We collected data of O, C (p,p') at RCNP and measured both the excitation energy (Ex=5-30MeV) and the energy of γ-rays (Eγ) in the the proton scattering angles of 0°-3.5°, and forγ-ray above 2 MeV. The purpose was to measure the branching ratios of γ-ray emission from excited states above 5 MeV including giant resonances of 16O and 12C. We looked at the correlation between Ex and Eγ. We found that the observed γ-rays are consistent with the picture which was predicted originally by Langanke et al.(Phys.Rev.Lett.76,2629,1996). Namely, the giant resonances mainly decay by nucleon emission. Some of these decays go to excited states in daugher nuclei. These excited states will decay by γ emission. We observe γ-rays about 5-7 MeV and almost no γ-rays above 10 MeV for 16O data. We expect to determine the γ-ray emission probability from the giant resonances (Ex=16-27 MeV) with accuracy of 10% systematic error for each 1MeV step of Ex soon.

Free Research Field

素粒子物理学