Alpha Decay in the Complex Energy Shell Model

TL;DR

This paper uses a complex-energy shell model to microscopically describe alpha decay in heavy nuclei, accurately reproducing known decay widths and predicting new half-life limits without explicitly modeling alpha clustering.

Contribution

It introduces a complex-energy shell model approach that accounts for both bound and unbound states to describe alpha decay microscopically, including the treatment of the norm kernel.

Findings

Reproduces experimental alpha-decay width of 212Po

Predicts an upper limit for 104Te half-life as 5.5x10^{-7} sec

Demonstrates the model's capability for heavy nuclei with valence nucleons

Abstract

Alpha emission from a nucleus is a fundamental decay process in which the alpha particle formed inside the nucleus tunnels out through the potential barrier. We describe alpha decay of $^{212}$Po and $^{104}$Te by means of the configuration interaction approach. To compute the preformation factor and penetrability, we use the complex-energy shell model with a separable T=1 interaction. The single-particle space is expanded in a Woods-Saxon basis that consists of bound and unbound resonant states. Special attention is paid to the treatment of the norm kernel appearing in the definition of the formation amplitude that guarantees the normalization of the channel function. Without explicitly considering the alpha-cluster component in the wave function of the parent nucleus, we reproduce the experimental alpha-decay width of $^{212}$Po and predict an upper limit of T_{1/2}=5.5x10^{-7} sec for the half-life of $^{104}$Te. The complex-energy shell model in a large valence configuration space is capable of providing a microscopic description of the alpha decay of heavy nuclei having two valence protons and two valence neutrons outside the doubly magic core. The inclusion of proton-neutron interaction between the valence nucleons is likely to shorten the predicted half-live of $^{104}$Te.