Spectroscopy of short-lived radioactive molecules: A sensitive laboratory for new physics

Abstract

The study of molecular systems provides exceptional opportunities for the exploration of the fundamental laws of nature and for the search for physics beyond the Standard Model of particle physics. Measurements of molecules composed of naturally occurring nuclei have provided the most stringent upper bounds to the electron electric dipole moment to date, and offer a route to investigate the violation of fundamental symmetries with unprecedented sensitivity. Radioactive molecules - where one or more of their atoms possesses a radioactive nucleus - can contain heavy and deformed nuclei, offering superior sensitivity for EDM measurements as well as for other symmetry-violating effects. Radium monofluoride, RaF, is of particular interest as it is predicted to have an appropriate electronic structure for direct laser cooling. Furthermore, some Ra isotopes are known to be octupole deformed, thereby resulting in a large enhancement of their symmetry-violating nuclear moments. Until now,however, no experimental measurements of RaF have been performed, and their study is impeded by major experimental challenges, as no stable isotopes of radium exist. Here, we present a novel experimental approach to study short-lived radioactive molecules using the highly sensitive collinear resonance ionisation method. With this technique we have measured, for the first time, the energetically low-lying electronic states for each of the isotopically pure RaF molecules at the ISOLDE-CERN. Our results provide strong evidence of the existence of a suitable laser-cooling scheme for these molecules and constitute a pivotal step towards high-precision studies in these systems. Our findings open up new opportunities in the synthesis, manipulation and study of short-lived radioactive molecules, which will have a direct impact in many-body physics, astrophysics, nuclear structure, and fundamental physics research.

Submitted

References in corpus (6)

• Magneto-optical trapping of a diatomic molecule
• Time-reversal symmetry violation in molecules induced by nuclear magnetic quadrupole moments
• Evolution of Octupole Deformation in Radium Nuclei from Coulomb Excitation of Radioactive ${}^{222}$Ra and ${}^{228}$Ra Beams
• Ab initio study of radium monofluoride, RaF, as a candidate to search for P- and T,P- violation effects
• Electric dipole moments of atoms and molecules produced by enhanced nuclear Schiff moments
• Electric dipole moments of actinide atoms and RaO molecule

Cited by in corpus (55)

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• Prospects for assembling ultracold radioactive molecules from laser-cooled atoms
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• $\mathcal{P}$,$\mathcal{T}$-odd effects for RaOH molecule in the excited vibrational state
• Characterizing the Fundamental Bending Vibration of a Linear Polyatomic Molecule for Symmetry Violation Searches
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• Pinning down electron correlations in RaF via spectroscopy of excited states and high-accuracy relativistic quantum chemistry
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• Kinetic-beam-energy determination via collinear laser spectroscopy
• Quantum-Enhanced Metrology for Molecular Symmetry Violation using Decoherence-Free Subspaces
• Theoretical molecular spectroscopy of actinide compounds: The ThO molecule
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• Laser cooling of barium monofluoride molecules using synthesized optical spectra
• Accurate theoretical determination of the ionization potentials of CaF, SrF, and BaF
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• Relativistic Exact Two-Component Coupled-Cluster Study of Molecular Sensitivity Factors for Nuclear Schiff Moments
• Ab initio study and assignment of electronic states in molecular RaCl
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• Laser cooling and trapping of ${}^{224}$Ra${}^{+}$
• Radium-containing molecular cations amenable for laser cooling
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• Parity and time-reversal symmetry violation in diatomic molecules: LaO, LaS and LuO
• $\mathcal{C}\mathcal{P}$-violation sensitivity of closed-shell radium-containing polyatomic molecular ions
• Towards CP Violation Studies on Superheavy Molecules: Theoretical and Experimental Perspective
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• A cold electron-impact ion source driven by a photo-cathode -- New opportunities for the delivery of radioactive molecular beams?
• Optical cycling in charged complexes with Ra-N bonds
• Theoretical determination of the ionization potentials of ScF, YF, LaF and AcF
• High-Efficiency Quantum-State Detection of ThF${}^{+}$ with Resonance-Enhanced Multiphoton Asymmetric Dissociation
• Voltage scanning and technical upgrades at the Collinear Resonance Ionization Spectroscopy experiment
• Production and spectroscopy of cold radioactive molecules
• Ionization potential of radium monofluoride
• Relativistic quintuple-zeta basis sets for the s block
• Modelling of transient interference phenomena in collinear laser spectroscopy
• Laser fluence-dependent production of molecular thorium ions in different charge states for trapped-ion experiments
• What is the diatomic molecule with the largest dipole moment?
• Commissioning and Full Realization of the PLASEN System at BRIF
• Radioactive Molecules as Laboratories of Fundamental Physics
• Nuclear Electric Quadrupole Moment-Induced Parity Doubling in Molecules for Symmetry-Violation Searches