Observation of $β$-delayed two-proton emission in the decay of $^{22}$Si

X.X. Xu , C.J. Lin , L.J. Sun , J.S. Wang , Y.H. Lam , J. Lee , D.Q. Fang , Z.H. Li , N.A. Smirnova (1) , C.X. Yuan , L. Yang , Y.T. Wang , J. Li , N.R. Ma , K. Wang , H.L. Zang , H.W. Wang , C. Li , M.L. Liu , J.G. Wang , C.Z. Shi , M.W. Nie , X.F. Li , H. Li , J.B. Ma , P. Ma , S.L. Jin , M.R. Huang , Z. Bai , F. Yang , H.M. Jia , Z.H. Liu , D.X. Wang , Y.Y. Yang , Y.J. Zhou , W.H. Ma , J. Chen , Z.G. Hu , M. Wang , Y.H. Zhang , X.W. Ma , X.H. Zhou , Y.G. Ma , H.S. Xu , G.Q. Xiao , H.Q. Zhang

1 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan

The decay of the lightest nucleus with Tz=−3 , 22 Si, was studied by a silicon array. A charged-particle group at 5600 (70) keV in the decay-energy spectrum was identified experimentally as β -delayed two-proton emission from the isobaric analog state (IAS) of 22 Al. Experimental results of the IAS fed by a superallowed Fermi transition were compared with our large-scale shell-model calculations. The ground-state mass of 22 Si was obtained indirectly in the experiment for the first time. Two-proton separation energy for 22 Si is deduced to be −108 (125) keV, which indicates that it is a very marginal candidate for two-proton ground-state emission.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

X.X. Xu, C.J. Lin, L.J. Sun, J.S. Wang, Y.H. Lam, et al.. Observation of $β$-delayed two-proton emission in the decay of $^{22}$Si. Phys.Lett.B, 2017, 766, pp.312-316. ⟨10.1016/j.physletb.2017.01.028⟩. ⟨hal-01554732⟩