β-delayed two-proton decay of 27S at the proton-drip line

The beta-delayed two-proton (beta 2p) decay of S-27 was studied using a state-of-the-art silicon array and Clover-type HPGe detectors. An energy peak at 6372(15) keV with a branching ratio of 2.4(5)% in the decay-energy spectrum was identified as a two-proton transition via the isobaric-analog state in P-27 to the ground state of Al-25 in the beta decay of S-27. Two-proton angular correlations were measured by the silicon array to study the mechanism of two-proton emission. Based on experimental results and Monte Carlo simulations, it was found that the main mechanism for the emission of beta 2p by S-27 is of sequential nature.