Speaker
Description
So far, double charge exchange reactions have been less explored than single charge exchange reactions. We have revisited double charge exchange reactions and found their discovery potentials in two cases: one is production of a tetraneutron state and the other is a search for double Gamow-Teller Giant resonances. In the both cases, new techniques which exploit properties of exotic nuclei have been used[1].
The first case is a production of tetraneutron state via the double charge exchange 4He(8He; 8Be) reaction. This reaction with a large positiveQ-value (exothermic) is particularly efficient in producing the fragile tetraneutron state with a recoilless manner. We have identified a (narrow) peak that can be a candidate of the tetraneutron state[2]. The existence of the state close to the threshold may indicate
necessity of force(s) that is attractive among neutrons.
The second case is a search for double Gamow-Teller giant resonances (DGTGR). DGTGR has been kept yet-to-be-discovered since the first theoretical prediction in 1989[3]. We have started an experimental program to search for DGTGR with a newly-invented method based on use of the heavy-ion double charge exchange (12C;12 Be(0+2
))[4]. This reaction has strong points that are missing in previously employed reactions and is quite efficient in populating DGTGR. In the workshop, results of the first experiment performed for a 48Ca target with a 100-MeV 12C
beam at RCNP, Osaka University are presented.
References
[1] T. Uesaka et al., Progress of Theoretical Physics 196, 150 (2012).
[2] K. Kisamori, S. Shimoura et al., Physical Review Letters 116, 052501 (2016).
[3] N. Auerbach, L. Zamick, and D. Zheng, Annals of Physics 192, 77 (1989).
[4] M. Takaki, T. Uesaka et al., presentation in INPC2016, Adelaide, Australia,
Septempber, 2016.
