A candidate of a tetra-neutron state populated by 4He(8He,8Be) reaction by Dr. Keiichi Kisamori (RNC Spin isospin Laboratory)
木佐森 慶一 氏 (理化学研究所仁科加速器研究センター上坂スピン・アイソスピン研究室)
Dr. Keiichi Kisamori (RNC Spin isospin Laboratory)
=Place and Time=
7月21日（火）13：30- RIBF 大会議室
21st July(Tue.), 13:30- at RIBF Conference hall
A candidate of a tetra-neutron state populated by 4He(8He,8Be) reaction
A possible existence of the tetra-neutron system forming a resonance state is still an open and fascinating question, while theoretical and experimental studies suggest that the tetra-neutron forming a bound state does not exist. Search of a tetra-neutron state has been performed by measuring the double-charge exchange reaction 4He(8He,8Be) at 186 MeV/u at RIBF with the SHARAQ spectrometer. Utilizing large positive Q-value of the (8He,8Be) reaction, almost recoil-less condition of the four-neutron system was achieved so as to obtain weakly interacting four-neutron systems efficiently. A candidate of a tetra-neutron state has been found with 4.9 σ significance level at the energy of 0.83 ± 0.65(stat.) ± 1.25(sys.) MeV above the threshold of four-neutron decay. The detail of the experiment, its result and a possible interpretation will be presented.