Alpha-decay from $^{44}$Ti: Microscopic alpha half-life calculation using normalized spectroscopic factor

TL;DR

This paper presents a microscopic calculation of alpha decay half-lives for $^{44}$Ti using the Gamow Shell Model and a normalized spectroscopic factor, providing insights into clusterization and decay properties of excited states.

Contribution

It introduces a robust protocol for calculating normalized spectroscopic factors and applies it to alpha decay in $^{44}$Ti, combining structure and reaction models.

Findings

Normalized spectroscopic factors are calculated for $^{44}$Ti states.

Excited states show increased clustering near alpha threshold.

Alpha half-life for a near-threshold state is approximately 5 microseconds.

Abstract

The microscopic description of alpha decay from the nucleons' degree of freedom involves a two-step process. The first consists of the clusterization of neutron and proton pairs; the second involves the tunneling process. A robust protocol for calculating the normalized spectroscopic factor, as defined by Fliessbach, and its error is established and used for calculating the alpha-width for the $0^+$ states of the nucleus $^{44}$Ti. The Gamow Shell Model is used to calculate the structure part of the alpha-decay, while the Gamow wave function determines the reaction part. The conventional and normalized spectroscopic factors are calculated for the ground and excited $0^+$ states of $^{44}$Ti and the alpha-width and half-life of the excited states. A near alpha-threshold state has an alpha half-life of 5 $\mu$sec. The normalization does not appreciably modify the ground-state clusterization, while the excited states do. The non-resonant continuum significantly increases the clustering of some of the excited states, particularly the $T=2$ state. The normalized formation amplitude looks like a single-particle wave function.