Beta-decay study of Tz =-2 proton-rich nucleus 24Si

beta-decay spectroscopy on a T-z = -2 proton-rich nucleus 24 Si was performed. The decay scheme of 24 Si was reconstructed by the beta-delayed gamma-ray and proton measurements. Two beta branches to the bound 1(1)(+) and 1(2)(+) states in Al-24 were observed for the first time. The observation of the allowed transition firmly established the spin-parity assignment for the 1(2)(+) states. The branching ratios to the 1(1)(+) and 1(2)(+) states were determined to be 31(4)% and 23.9(15)%, respectively. The branching ratios to three unbound states in Al-24 including a new level at 6.735 MeV were also determined for the first time. The level structure of Al-24 was compared with its mirror nucleus Na-24. The Thomas-Ehrman shift on the 1(2)(+) state indicates s-wave dominance in the state as well as a characteristic behavior of the weakly bound s-wave proton in Al-24.