Recollision induced nuclear excitation of $^{229}$Th

TL;DR

This paper refines a laser-driven electron recollision method to excite the $^{229}$Th nucleus, using improved theoretical cross sections that significantly increase excitation probability estimates, and explores laser parameter dependencies.

Contribution

It provides an enhanced theoretical framework with updated cross sections and detailed analysis of laser parameter effects for nuclear excitation via electron recollision.

Findings

Distorted-wave cross sections are 5-6 orders of magnitude higher than plane-wave results.

Excitation probability is approximately 10^{-12} per nucleus per femtosecond laser pulse.

Laser parameters significantly influence the excitation probability.

Abstract

Previously we proposed a new approach of exciting the $^{229}$Th nucleus using laser-driven electron recollision [W. Wang et al., Phys. Rev. Lett. 127, 052501 (2021)]. The current article is aimed to elaborate the method by explaining further theoretical details and presenting extended new results. The method has also been improved by adopting the electronic excitation cross sections calculated recently by Tkalya [E. V. Tkalya, Phys. Rev. Lett. 124, 242501 (2020)]. The new cross sections are obtained from Dirac distorted-wave calculations instead of from Dirac plane-wave calculations as we used previously. The distorted-wave cross sections are shown to be 5 to 6 orders of magnitude higher than the plane-wave results. With the excitation cross sections updated, the probability of isomeric excitation of $^{229}$Th from electron recollision is calculated to be on the order of $10^{-12}$ per nucleus per (femtosecond) laser pulse. Dependency of the excitation probability on various laser parameters is calculated and discussed, including the laser intensity, the laser wavelength, and the laser pulse duration.