Decay of low-lying ¹²C resonances within a 3α cluster model

We compute energy distributions of three α-particles emerging from the decay of ¹²C resonances by means of the hyperspherical adiabatic expansion method combined with complex scaling. The large distance continuum properties of the wave functions are crucial and must be accurately calculated. The substantial changes from small to large distances determine the decay mechanisms. We illustrate by computing the energy distributions from decays of the 1⁺ and 3⁻-resonances in ¹²C. These states are dominated by direct and sequential decays into the three-body continuum respectively.