Formation of gaseous, doubly charged cerium monofluoride CeF$^{2+}$ and its sensitivity to new physics

TL;DR

This paper explores the formation and properties of CeF$^{2+}$ ions as a stable surrogate for $^{229}$PaF$^{3+}$ in probing physics beyond the Standard Model, focusing on their electronic structure and potential for symmetry violation searches.

Contribution

It introduces CeF$^{2+}$ as a stable, valence-isoelectronic surrogate for $^{229}$PaF$^{3+}$, with quantum chemical analysis predicting its sensitivity to new physics.

Findings

CeF$^{2+}$ ions can be formed and identified in the gas phase.

Quantum calculations show CeF$^{2+}$ has similar electronic structure to $^{229}$PaF$^{3+}$.

CeF$^{2+}$ may be sensitive to $ ext{P,T}$-odd properties, useful for symmetry violation studies.

Abstract

Tricationic protactinium monofluoride ($^{229}$PaF$^{3+}$) has been proposed as a candidate for probing physics beyond the Standard Model of particle physics. Since studies with $^{229}$PaF$^{3+}$ require significant experimental advances, we exploit the stable, valence-isoelectronic dicationic cerium monofluoride (CeF$^{2+}$) as a surrogate. Gas-phase fluorinated-cerium molecular ions are formed and identified using the Off-Line Ion Source and TITAN mass measurement facilities at TRIUMF. Quantum chemical calculations are performed on the electronic structure of CeF$^{2+}$, revealing a parallel to that of $^{229}$PaF$^{3+}$. Moreover, these calculations provide estimates on the sensitivity of CeF$^{2+}$ itself to various $\mathcal{P,T}$-odd properties. A brief discourse on the specifics of the quantum control of CeF$^{2+}$ is presented which anticipates future searches for symmetry violations.