第12回 卓越セミナー

第12回 卓越セミナー

2023年11月01日
  • 日時:2023年11月16日(木)15:10-16:40
  • 場所:理学研究科D307講義室

発表者: 益田 遼太郎さん(化学専攻)
タイトル:Development of rare gas matrix isolation apparatus for observation of γ rays from 229mTh

アブストラクト
229mTh is an excited nucleus and has an extremely low excitation energy of 8.338 ± 0.024 eV, which is 3~6 orders of magnitude lower than other those of isomers. Because of this feature, the decay path of 229mTh is expected to change depending on its chemical state. 229mTh is also the only one candidate for a nuclear clock. A nuclear clock is expected to be able to predict earthquakes and observe changes in physical constants with an accuracy of 10-19. However, it is difficult to stably maintain the chemical state in which 229mTh is expected to emit γ ray. There is only one report of direct observation of γ ray from 229mTh, but the chemical state of Th in this experiment is unclear. Therefore, we focused on the rare-gas matrix isolation method in order to try photon observation for 229mTh+. The chemical state of 229mTh ions in rare-gas matrix is expected to emit γ-rays.
In this presentation, we report on the basic experiments using a developed rare-gas matrix isolation apparatus.

発表者: 宮滝 雅己さん(物理学専攻)
タイトル:A study on online event selection using a neural network implemented on FPGA in the COMET Phase-I experiment

アブストラクト
The muon-electron conversion process is strictly forbidden in the standard model of particle physics, however, many physics models beyond the standard model predict it could happen with a probability O(10^-18) ~O(10^-15). The COMET experiment aims to discover this process by employing a high-intensity muon beam at J-APRC in Tokai, Ibaraki, Japan. In the experiment, the timing of data taking is determined by “trigger”. Trigger needs to illuminate background events produced by muon beam while keeping a high signal efficiency. I'm conducting the research on development of trigger system for the experiment and investigating the state-of-the-art machine learning technique to improve the trigger performance. In this talk, I'm going to give a talk on the status of my study.