2023 Fiscal Year Research-status Report
Precision spectroscopy of Hydrogen-5 as a benchmark for the Hyperhydrogen-6 nucleus
| Project/Area Number |
23KF0297
|
|---|
| Research Institution | Institute of Physical and Chemical Research |
|---|
Principal Investigator |
上坂 友洋 国立研究開発法人理化学研究所, 開拓研究本部, 主任研究員 (60322020)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
POHL THOMAS 国立研究開発法人理化学研究所, 開拓研究本部, 外国人特別研究員
|
|---|
| Project Period (FY) |
2023-11-15 – 2026-03-31
|
| Keywords | Knockout reaction / Heavy hydrogen / Hyper nucleus / Invariant mass |
|---|
| Outline of Annual Research Achievements |
In the proposed research, the precise spectroscopy of hydrogen 5 (5H) will be conducted using the (p,2p) knockout reaction on a helium 6 (6He) beam produced at the RIKEN RI Beam Factory (RIBF). The ground state of 5H is known to be unbound and decays into triton + 2 neutrons immediately. Invariant mass spectroscopy with the SAMURAI setup equipped with the high-efficiency neutron detector array NEBULA will enable determination of the energy and width of the 5H ground state with unprecedently high-statistics and high-resolution.
The fellow was introduced into the group of Dr. Uesaka and started discussing and the realization of the proposal with members of the group. In particular, the necessity of a development of the hodoscope plastic scintillator array for detection of decay tritons with a better position resolution has been addressed. To strengthen his expertise in direct reactions, he joined the work of the ONOKORO collaboration, which focuses on the measurement of cluster removal reactions. He started his current task to implement a simulation framework, which is needed for the optimization of the experimental setup and as a tool to prepare future experiments. He participated in the preparation of an experimental campaign of (p,pX) knockout reactions at RNCP, Osaka to learn more about the project and gain experimental practice of knockout reaction at intermediate energies.
|
| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The fellow is currently working on a concept and the realization to guarantee a successful measurement of 6He(p,2p) reaction under inverse kinematics. This includes detailed simulation of the SAMURAI experiment and design of the hodoscope plastic scintillator array. The measurement was planned to take place in autumn 2024, as part of an experimental campaign using a 6He beam. However, this experimental campaign and so his measurement has been postponed to spring 2025 due to the accelerator operation schedule. In addition, he will participate at experimental campaigns to learn about the complex setup of the SAMURAI spectrometer, so that the measurement in 2025 will be successful.
|
| Strategy for Future Research Activity |
Since the experimental campaign has been postponed to spring 2025, all boundary conditions are not yet clear. The planning will proceed within next fiscal year and according to that the preparation and development of the fellow’s measurement will be continued. He plans to present his measurement at the yearly SAMURAI international workshop held at Korean Institute of Basic Science in July, 2024, to discuss the successful realization.
The development of the simulation framework for the ONOKORO collaboration is the most critical part for the success of planned experiment. The fellow will continue the development and it is foreseen to apply it to plan future experiments. In addition, he will start to analyze direct reaction data using the distorted-wave impulse approximation theory to strengthen his analysis expertise. Furthermore, it is foreseen, that the fellow will participate at experimental SAMURAI campaigns to deepen his understanding of the complex measurement system.
|
| Causes of Carryover |
The fellow made a design of the detector system newly introduced by the JSPS budget in FY2023 and 2024. After the detailed design and negotiation with the fabrication company, it turned out that ordering the whole detectors at once is the more efficient and cost-effective solution. Thus the fellow decided to carry over the FY2023 budget and construct the detector system in FY2024 by combining the budget in two years.
|
