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

$ \beta$ -decay spectroscopy on a T z = - 2 proton-rich nucleus 24Si was performed. The decay scheme of 24Si was reconstructed by the $ \beta$ -delayed $ \gamma$ -ray and proton measurements. Two $ \beta$ branches to the bound 11 + and 12 + states in 24Al were observed for the first time. The observation of the allowed transition firmly established the spin-parity assignment for the 12 + states. The branching ratios to the 11 + and 12 + states were determined to be 31(4)% and 23.9(15)%, respectively. The branching ratios to three unbound states in 24Al including a new level at 6.735MeV were also determined for the first time. The level structure of 24Al was compared with its mirror nucleus 24Na . The Thomas-Ehrman shift on the 12 + state indicates s -wave dominance in the state as well as a characteristic behavior of the weakly bound s -wave proton in 24Al .