Two-proton radioactivity: The interesting case of 67kr and further studies

Giovinazzo, J.; Goigoux, T.; Blank, B.; Ascher, P.; Gerbaux, M.; Grevy, S.; Kurtukian-Nieto, T.; Magron, C.; Doornenbal, P.; Fukuda, N.; Inabe, N.; Kiss, G. G.; Kubo, T.; Kubono, S.; Nishimura, S.; Sakurai, H.; Shimizu, Y.; Sidong, C.; Soderstrom, P. -A.; Sumikama, T.; Suzuki, H.; Takeda, H.; Vi, P.; Wu, J.; Ahn, D. S.; Agramunt, J.; Algora, A.; Guadilla, V.; Montaner-Piza, A.; Morales, A. I.; Orrigo, S. E. A.; Rubio, B.; Fujita, Y.; Tanaka, M.; Gelletly, W.; Aguilera, P.; Molina, F.; Diel, F.; Lubos, D.; De Angelis, G.; Napoli, D.; Borcea, C.; Boso, A.; Cakirli, R. B.; Ganioglu, E.; Chiba, J.; Nishimura, D.; Oikawa, H.; Takei, Y.; Yagi, S.; Wimmer, K.; De France, G.; Go, S.; Brown, B. A.

doi:10.5506/APhysPolB.51.577

We report on the observation of 67Kr that has been produced in an experiment performed at the RIKEN/BigRIPS facility. The two-proton decay of 67Kr has been evidenced and this nucleus is thus the fourth observed long lived ground-state two-proton emitter, after 45Fe, 48Ni and 54Zn. In addition, the decay of several isotopes in the mass region has been investigated. While for previous cases of two-proton radioactivity, the theoretical models could reproduce the measured data, this is not the case anymore for 67Kr. Two interpretations have been proposed to explain this discrepancy: A transition between real two-proton and sequential decay or the influence of deformation. These hypotheses will be tested in future experiments by measuring the angular and energy correlations of the emitted protons.