Speaker
Description
Recent results and perspectives on hypernuclear physics are summarized based on experimental data at J-PARC and other facilities, and their connection to high-density matter in neutrons stars is also discussed.
Precise investigation of few-body $\Lambda$ hypernuclei ($^3_\Lambda$H, $^4_\Lambda$H, and $^4_\Lambda$He) is of vital importance in determining the hyperon-nucleon interaction. There have been serious puzzles in those light hypernuclei, the hypertriton puzzle (the inconsistency between the measured lifetime and binding energy of $^3_\Lambda$H) and the charge symmetry breaking problem (the observed large difference between $^4_\Lambda$H and $^4_\Lambda$He level energies). The present status of studies at J-PARC, MAMI, ALICE and STAR are reviewed.
As for doubly-strange nuclear systems, recent results of a ($K^-,K^+$) reaction experiment indicate existence of $^{12}_\Xi$Be bound states, and an updated experiment (J-PARC E70) is currently investigating details of those states. The status of recent $\Xi$ atomic X-ray measurements and an H-dibaryon search experiment are also shown.
In order to solve the so-called “hyperon puzzle”, high-quality hyperon-nucleon scattering data are also essential because the precisely determined baryon-baryon interactions in the free space are necessary to extract information on density-dependent baryon-baryon interactions in nuclear matter through hypernuclear data. After the successful $\Sigma$-proton scattering experiment at J-PARC, a new experiment on $\Lambda$-proton scattering has started at SPring-8. On the other hand, precise measurements of medium and heavy $\Lambda$ hypernuclear binding energies are planned at JLab and then at the extended Hadron Facility at J-PARC. Those efforts will determine the strength of the $\Lambda$$N$$N$ three-body repulsive force and clarify whether hyperons exist in neutron stars or not.
