A. Czihaly | Searcharxiv

arXiv2026

First direct measurement of $^{48}$Ca single $\beta$-decay Q value with the TITAN Penning trap

Neutrinoless double $\beta$-decay (0$\nu\beta\beta$), if observed, would provide unequivocal evidence of physics beyond the Standard Model. $^{48}$Ca is an interesting candidate system to study because it has the largest Q value among all 2$\beta$ transitions and is also unstable against single $\beta$-decay. The observation of both $\beta$ and 2$\beta$-decay in the same isotope would provide a unique opportunity to benchmark theoretical calculations of $\beta$ and 2$\beta$-decay matrix elements and could provide insight on the quenching of the axial vector coupling constant, g$_A$. We performed a precise measurement of the $^{48}$Ca $\beta$-decay Q value using the TITAN Penning trap mass spectrometer at the TRIUMF facility. This was achieved through cyclotron frequency ratio measurements of $^{48}$Ca$^{+}$/$^{48}$Sc$^{+}$ and $^{48}$Sc$^{+}$/$^{48}$Ti$^{+}$ using the Time-of-Flight Ion Cyclotron Resonance technique. The $^{48}$Ca $\beta$-decay Q value was determined to be 279.14(50) keV, a factor of 10 more precise than the previous value given in the 2020 Atomic Mass Evaluation [Chin. Phys. C 45, 030003 (2021)]. This Q value was used to determine the $^{48}$Ca $\beta$-decay partial half-life, with the result $T_{1/2}^{\beta}$ = 5.09(5) x 10$^{20}$ ($g_{A}^{-2}$) y. Our $^{48}$Ca $\beta$-decay half-life was determined to a precision of 1%, a factor of 30 improvement compared to calculations with the previous Q value. Our result is marginally closer to the experimental lower limit $T_{1/2}^{\beta}$ > 1.1 x 10$^{20}$ y, but still a factor 5 longer. It is also a factor of 10 longer than the observed 2$\nu\beta\beta$ decay mode with $T_{1/2}^{2\nu\beta\beta} = 5.96^{+1.39}_{-1.08}$ x 10$^{19}$ y. Hence, it could be possible to observe $^{48}$Ca $\beta$-decay in future experiments, strengthening the potential importance of $^{48}$Ca to benchmark nuclear structure and 2$\beta$-decay studies.

nucl-ex↗

arXiv2026

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

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.

physics.atom-ph↗

arXiv2025

Refined topology of the N = 20 island of inversion with high precision mass measurements of $^{31-33}$Na and $^{31-35}$Mg

Mass measurements of $^{31-33}$Na and $^{31-35}$Mg using the TITAN MR-TOF-MS at TRIUMF's ISAC facility are presented, with the uncertainty of the $^{33}$Na mass reduced by over two orders of magnitude. The excellent performance of the MR-TOF-MS has also allowed the discovery of a millisecond isomer in $^{32}$Na. The precision obtained shows that the binding energy of the normally closed N = 20 neutron shell reaches a minimum for $^{32}$Mg but increases significantly for $^{31}$Na, hinting at the possibility of enhanced shell strength toward the unbound $^{28}$O. We compare the results with new ab initio predictions that raise intriguing questions of nuclear structure beyond the dripline.

nucl-ex↗