Isospin Symmetry in the Structure Study of Unstable Nuclei

Abstract

Assuming isospin T is a good quantum number, the analog states of the low-lying states in T z = ′ (T 0 +1) nuclei can be found as excited T 0 +1 states in T z = ′T 0 nuclei. Therefore, if To + 1 states are identified in theexcited region of T z = ′T 0 nuclei, the structure of unstable nuclei with T z = ′(T 0 + 1) can be deduced. We measured and compared the transition strengths to pairs of excited analog states in inelastic and charge-exchange reactions on the same target nucleus. The T values of these analog states were identified by using the fact that the transition strengths to them are different depending on T. The identification of T = ½ and 3/2 nature of analog M1 and GT states in the mirror nuclei pair 2 7 Al and 2 7 Si is reported by comparing the transition strengths in high-resolution 2 7 Al(p,p') and 2 7 Al( 3 He, t) 2 7 Si reactions at 0°. The identified T = 3/2 states are analogous to the low-lying states of 2 7 Mg, which plays an important role in rp-process of nucleosynthesis.