Issue
EPL
Volume 85, Number 2, January 2009
Article Number 20006
Number of page(s) 5
Section General
DOI http://dx.doi.org/10.1209/0295-5075/85/20006
Published online 30 January 2009
EPL, 85 (2009) 20006
DOI: 10.1209/0295-5075/85/20006

Quantum time scales in alpha tunneling

N. G. Kelkar1, H. M. Castañeda1, 2 and M. Nowakowski1

1   Departamento de Fisica, Universidad de los Andes - Cra. 1E No. 18A-10, Bogota, Colombia
2   Max-Planck-Institut für Kernphysik - Saupfercheckweg 1, 69117 Heidelberg, Germany, EU

nkelkar@uniandes.edu.co

received 4 October 2008; accepted in final form 19 December 2008; published January 2009
published online 30 January 2009

Abstract
The theoretical treatment of alpha-decay by Gamow is revisited by investigating the quantum time scales in tunneling. The time spent by an alpha-particle in front of the barrier and traversing it before escape is evaluated using microscopic alpha-nucleus potentials. The half-life of a nucleus is shown to correspond to the time spent by the alpha knocking in front of the barrier. Calculations for medium and super heavy nuclei show that from a multitude of available tunneling time definitions, the transmission dwell time gives the bulk of the lifetime of the decaying state, in most cases.

PACS
03.65.Xp - Tunneling, traversal time, quantum Zeno dynamics.
21.10.Tg - Lifetimes, widths.
23.60.+e - $\alpha$ decay.

© EPLA 2009