arXiv subjects

A. McGlone

Publications and source records attributed to A. McGlone.

5 recordsLinked to original sources

arXiv2026

Energies and lifetimes of the 9p and 10p excited states in atomic francium

We present the first measurement of 9p 2P1/2,3/2 and 10p 2P1/2,3/2 excited levels absolute wavenumbers and radiative lifetime in francium. We used the Collinear Resonance Ionization Spectroscopy (CRIS) technique, applied on a beam of 221Fr atoms. Prior to this work, no experimental data existed for francium p-states with n > 8. The results provide a precision experimental test of relativistic coupled-cluster theory for the heaviest alkali, showing good agreement for lifetimes and relative excitation energies, despite a residual global offset in absolute energies.

physics.atom-ph↗

arXiv2025

$^{61}$Cr as a Doorway to the N = 40 Island of Inversion

This paper reports on the measurement of the ground-state spin and nuclear magnetic dipole moment of $^{61}$Cr. The radioactive ion beam was produced at the CERN-ISOLDE facility and was probed using high-resolution resonance ionization laser spectroscopy with the CRIS apparatus. The present ground-state spin measurement $I = \frac{1}{2}$, differing from the previously adopted $I =(\frac{5}{2})$, has significant consequences on the interpretation of existing beta decay data and nuclear structure in the region. The structure and shape of $^{61}$Cr is interpreted with state-of-the-art Large-Scale Shell Model and Discrete-Non-Orthogonal Shell Model calculations. From the measured magnetic dipole moment $μ(^{61}$Cr$)=+0.539(7)~μ_N$ and the theoretical findings, its configuration is understood to be driven by 2 particle - 2 hole neutron excitations with an unpaired $1p_{1/2}$ neutron. This establishes the western border of the $N=40$ Island Of Inversion (IoI), characterized by 4 particle - 4 hole neutron components. We discuss the shape evolution along the Cr isotopic chain as a quantum phase transition at the entrance of the $N=40$ IoI.

nucl-ex↗

arXiv2025

Laser spectroscopy and CP-violation sensitivity of actinium monofluoride

The apparent invariance of the strong nuclear force under combined charge conjugation and parity (CP) remains an open question in modern physics. Precision experiments with heavy atoms and molecules can provide stringent constraints on CP violation via searches for effects due to permanent electric dipole moments and other CP-odd properties in leptons, hadrons, and nuclei. Radioactive molecules have been proposed as highly sensitive probes for such searches, but experiments with most such molecules have so far been beyond technical reach. Here we report the first production and spectroscopic study of a gas-phase actinium molecule, $^{227}$AcF. We observe the predicted strongest electronic transition from the ground state, which is necessary for efficient readout in searches of symmetry-violating interactions. Furthermore, we perform electronic- and nuclear-structure calculations for $^{227}$AcF to determine its sensitivity to various CP-violating parameters, and find that a realistic, near-term experiment with a precision of 1 mHz would improve current constraints on the CP-violating parameter hyperspace by three orders of magnitude. Our results thus highlight the potential of $^{227}$AcF for exceptionally sensitive searches of CP violation.

physics.atom-ph↗

arXiv2024

Pinning down electron correlations in RaF via spectroscopy of excited states and high-accuracy relativistic quantum chemistry

We report the spectroscopy of the 14 lowest excited electronic states in the radioactive molecule radium monofluoride (RaF). The observed excitation energies are compared with fully relativistic state-of-the-art Fock-space coupled cluster (FS-RCC) calculations, which achieve an agreement of >=99.64% (within ~12 meV) with experiment for all states. Guided by theory, a firm assignment of the angular momentum and term symbol is made for 10 states and a tentative assignment for 4 states. The role of high-order electron correlation and quantum electrodynamics effects in the excitation energy of excited states is studied, found to be important for all states. Establishing the simultaneous accuracy and precision of calculations is an important step for research at the intersection of particle, nuclear, and chemical physics, including searches of physics beyond the Standard Model, for which RaF is a promising probe.

physics.atom-ph↗

arXiv2024

Radiative lifetime of the A 2Π1/2 state in RaF with relevance to laser cooling

The radiative lifetime of the $A$ $^2 Π_{1/2}$ (v=0) state in radium monofluoride (RaF) is measured to be 35(1) ns. The lifetime of this state and the related decay rate $Γ= 2.86(8) \times 10^7$ $s^{-1}$ are of relevance to the laser cooling of RaF via the optically closed $A$ $^2 Π_{1/2} \leftarrow X$ $^2Σ_{1/2}$ transition, which makes the molecule a promising probe to search for new physics. RaF is found to have a comparable photon-scattering rate to homoelectronic laser-coolable molecules. Thanks to its highly diagonal Franck-Condon matrix, it is expected to scatter an order of magnitude more photons than other molecules when using just 3 cooling lasers, before it decays to a dark state. The lifetime measurement in RaF is benchmarked by measuring the lifetime of the $8P_{3/2}$ state in Fr to be 83(3) ns, in agreement with literature.

physics.atom-ph↗