Time-evolution formalism in the complex scaling method: Application to the two-proton decay of ${}^6$Be

Abstract

We apply our complex-scaled time-evolution operator to the two-proton decay of ${}^6$Be. The nucleus is described as an $\alpha +p+p$ three-body system with explicit Jacobi-coordinate rearrangement and the realistic Argonne $v{8}^{\prime }$ NN interaction for the proton-proton subsystem. Starting from a confined initial wave packet, the decay dynamics are described by expansion over the complex-scaled eigenstates of the final Hamiltonian. The decay width extracted from the late-time survival probability agrees closely with that obtained from the CSM resonance pole. The time-dependent densities in different Jacobi coordinates reveal complementary aspects of the evolving three-body geometry, while the spin-singlet component remains dominant during the decay. In particular, the correlated two-proton configuration persists even in the presence of the strong short-range repulsion of the realistic NN interaction. These results demonstrate the applicability of the complex-scaled time-evolution framework to explicit three-body decay dynamics and provide a consistent description of the decay width, spatial evolution, and spin correlations of ${}^6$Be.

Comments: 12 pages, 11 figures