Sizeable beta-strength in 31Ar (β3p) decay

We present for the first time precise spectroscopic information on the recently discovered decay mode β-delayed 3p-emission. The detection of the 3p events gives an increased sensitivity to the high energy part of the Gamow–Teller strength distribution from the decay of 31Ar revealing that as much as 30% of the strength resides in the β3p-decay mode. A simplified description of how the main decay modes evolve as the excitation energy increases in 31Cl is provided.