2018 Fiscal Year Final Research Report
Search for double beta decay of xenon by polyhedral approach
| Project/Area Number |
16H06004
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| Research Category |
Grant-in-Aid for Young Scientists (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | The University of Tokyo |
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Principal Investigator |
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Keywords | 素粒子実験 / ニュートリノ / 二重ベータ崩壊 / 二重電子捕獲 / キセノン |
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| Outline of Final Research Achievements |
In this research, searches for double beta decays of xenon have been conducted in order to approach the nature of Majorana neutrinos. At first, a search for two-neutrino double electron capture on 124Xe, which is predicted within the Standard Model of particle physics but has not been experimentally observed, was performed. We searched for this process using 800 days of data taken with a large liquid xenon detector XMASS-I which is located 1000 m underground at the Kamioka Observatory. No significant signal was observed, and hence we set the most stringent lower limit on the half-life of the process to be >2.1E22 years.
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| Free Research Field |
素粒子実験、宇宙線実験
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| Academic Significance and Societal Importance of the Research Achievements |
本研究では124Xeのニュートリノを伴う二重電子捕獲の探索を行ったが、残念ながら有意な信号を捉えることはできなかった。その結果、この反応の半減期に対して世界でもっとも厳しい制限を与えることになったが、この結果は原子核反応を計算するための様々な理論モデルを改善するための新しいインプットになった。これは、今後ニュートリノを伴わない二重ベータ崩壊の半減期の予言精度を向上させることにつながると期待される。
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