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 .