2019
Yamaguchi Lab.
Nuclear astrophysics
The mechanism of how the stars shine and how stellar explosions, such as supernova, occur in the universe is explained as the works of tiny “atomic nuclei” in atoms. “Nuclear astrophysics” is the research field to connect huge stellar objects in the vast universe and tiny atomic nuclei. One major goal of the nuclear astrophysics is to answer the fundamental question, how and where were all the elements, which constitute the earth and all the creatures, created. After three minutes from the Big bang, the temperature of the universe is cooled down to the domain of nuclear reactions and the first “nucleosynthesis” is performed. Eventually many stars were created in the universe, and heavier elements were synthesized from lighter elements in them. Meanwhile, the nuclear force has dominated the fate of the stars, from the birth to the death.
The relevant thermonuclear reactions in starts cannot be understood only with the observation, and therefore many experiments on nuclear reactions with accelerators have been performed, revealing the nature of the stellar reactions. However, it was not an easy task to simulate the stellar environment, where a huge number of atoms are condensed with a high pressure, by an accelerator experiment on the earth. The difficulty mainly comes from 1) the stellar ambient energy is too low compared to typical accelerator or nuclear physics energy, and 2) unstable nuclei, which are not seen naturally on the earth, may play important roles.
Yamaguchi-Lab/Nuclear Astrophysics Group of CNS is tackling on the mysteries about the universe with world-wide researchers, using the unique facility “CRIB”, which can produce unstable-nuclei beams at the temperature of explosive stellar objects. The Big-bang nucleosynthesis, the first nucleosynthesis in the universe, has a big problem as the present theoretical model cannot reproduce the observed abundance of the lithium element. As for X-ray burst, which is the most frequent thermonulcear explosion in the universe, how the proton-rich nuclear process (rp-process) works is not well studied, and it is still difficult to predict the light curve precisely due to our limited knowledge. The galactic gamma-rays from Aluminum-26 nucleus are well observed, but their original stellar sites are not clearly identified. Yamaguchi-Lab is studying on these problems, and interesting results are coming up. Nuclear astrophysics is becoming one major topic among the nuclear physics all over the world, and we are working on unique studies with a very international environment, also having a solid stage of research in Japan.
Yako Lab.
Exotic nuclear reaction
Nuclei have macroscopi properties such as surface and shape. “Sticking” a nucleus by means of nuclear scattering can cause rotation or vibration. Since these phenomena, called nuclear collective excitations, reflect fundamental nature of nuclei like its hardness, they have become a major subject of research. Exotic nuclear reaction group will advance research on new aspects of nuclei and on interactions creating collectivities by using RI beams at RIBF.
Sakemi Lab.
Fundamental symmetry
The mechanism how the matter dominant universe has been created is studied with the fundamental symmetry breaking in heavy elements. The heavy elements can be used as the microscope to investigate the fundamental symmetry. We control the quantum state of heavy element by making use of laser cooling technology and search for the CP violation by precise quantum measurement using atomic interferometer.
NUSPEQ group
NUSPEQ group
We are studying various properties of nuclei over wide area of the nuclear chart by using nuclear reactions with secondary beams of exotic nuclei which have different numbers of neutrons and protons from those of stable nuclei.
Wave functions of loosely bound nucleons, change of magic numbers, exotic excitation modes, and reaction mechanisms are studied by utilizing suitable selectabilities of nuclear reactions by selecting suitable incident energies and targets.
For these purposes, we are developing high-resolution gamma-ray detectors, GRAPE, high-resolution magnetic analyzer, SHARAQ, and energy-degrading beam line, OEDO.
We are not recruiting graduate students this year.
Imai Lab.
DONUTS group
(Dynamics Of Nuclear quanTum Systems)
Nucleus is composed of neutrons and protons. We are studying the quantum many body phenomena, such as shape coexistence, exotic deformation, BEC-BCS crossover by employing unique experimental devicesand techniques. We are also pursuing the interdiciplinary research such as nuclear astrophysics and transmutation of nuclear waste. As the experimental devices, we are developing the RIB decelerator named OEDO, a large size tritium titanium target, and a high spin target. We are also developing the gamma ray detectors, recoiled particle detectors, and ultra-thin diamond detector.
Gunji Lab.
Quark physics
Our research is to create a new state of hot and dense matter composed of quarks and gluons (QGP), which existed up to a few milliseconds after the Big Bang, in the laboratory and to understand the characterization of QGP and early universe and the mechanisms of the formation of our ordinal hadronic matter. We are conducting ultra-relativistic high-energy heavy-ion collisions at RHIC (BNL) and LHC (CERN) accelerators and we participate in the international collaboration “ALICE” experiment at the LHC.