Wed·Jul 30, 2025Wednesday·July 30, 2025

1. 01*

   Nuclear excitation functions for medical isotope production: targeted radionuclide therapy via natIr(d,x)193mPt

   H. L. O. Ekeberg · A. S. Voyles · M. S. Basunia · J. C. Batchelder · L. A. Bernstein🇺🇸 · D. L. Bleul · K. C. W. Li🇿🇦 · E. M. Martinsen · E. F. Matthews🇺🇸 · J. T. Morrell · N. I. J. Pettersen · S. Siem🇳🇴

   193mPt is an Auger emitting radionuclide which may have therapeutic potential, particularly when labeled to the chemotherapeutic drug cisplatin. One challenge to broader explorations of its clinical potential is the need for production routes with high specific activity. As part of a larger campaign to address gaps in reaction data for emerging medical radionuclides, this work seeks to characterize the natIr(d,x) reactions as a potential production pathway for 193mPt. A stacked target irradiation, consisting of natural iridium, iron, nickel, and copper foils, was performed using a 33 MeV deuteron beam at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. This measurement, along with previous experimental data, suggests an energy window between 11 to 18 MeV to maximize the production and radiopurity of 193mPt. This experiment has yielded cross sections for 43 channels of deuteron-induced reactions from threshold to 30 MeV, including the first experimental results of natIr(d,x)188m1+g,190m1+gIr (cumulative), natNi(d,x)56,57,58m,58gCo (independent), natCu(d,x)61Co (cumulative) and natFe(d,x)53Fe, 48V (cumulative). The results were compared with literature data, the TENDL-2023 database, and default theoretical calculations from the TALYS-2.04, CoH-3.6.0, EMPIRE-3.2.3, and ALICE-2020 reaction modeling codes. This work presents another example of the lack of predictive capabilities for this set of modern nuclear-reaction modeling codes, and highlights the unsatisfactory modeling of experimental cross sections. Experimental data are important to improve the codes in general, and new experimental results can be used to improve the models. Finally, this measurement has revealed the need for an updated evaluation of the natCu(d,x)63Zn deuteron monitor reaction.

   nucl-exAppl.Radiat.Isot.(2026)·0 citations
2. 02*

   Shape evolution in neutron-rich odd-even ${}^{105-109}$Nb isotopes

   M. Abushawish🇫🇷 · E. H. Wang🇨🇳 · J. Dudouet🇫🇷 · A. Navin🇫🇷 · E. Clément🇫🇷 · G. Duchêne🇫🇷 · J. H. Hamilton🇺🇸 · A. Lemasson🇫🇷 · C. Michelagnoli🇫🇷 · O. Stezowski🇫🇷 · S. Bhattacharyya🇮🇳 · F. DidierJean🇫🇷 and 6 other authors

   Neutron-rich nuclei around $Z\sim 40$ exhibit multiple shape transitions. This region shows one of the sharpest transitions in the nuclear chart, from a spherical vibrator at $N=58$ to a strongly deformed prolate shape at $N=60$, with largest deformations seen for ${}_{38}$Sr and ${}_{40}$Zr. Below $Z=36$, a spherical-to-oblate transition is predicted, while above $Z=42$ and $N\ge 60$, the shape evolves from axial to triaxial. Even-$Z$ nuclei have been well studied, but odd-$Z$ isotopes such as Nb offer additional insights into these mechanisms. The Nb isotopes lie at the boundary between axially deformed Zr and triaxially deformed Mo nuclei. This work explores the structure of neutron-rich Nb nuclei up to $N=68$, aiming to understand shape evolution with isospin and the onset of triaxiality. Two complementary fission experiments were used: (i) ${}^{238}$U+${}^9$Be at GANIL in inverse kinematics with AGATA, EXOGAM, and VAMOS++, allowing prompt and delayed $\gamma$-ray spectroscopy with isotopic identification; (ii) spontaneous fission of ${}^{252}$Cf with the Gammasphere array providing high-fold $\gamma$-coincidence data. The level scheme of ${}^{105}$Nb was significantly extended with two new negative-parity bands. A revised scheme is proposed for ${}^{107}$Nb, differing from previous results, and new structures are reported in ${}^{109}$Nb. The signature splitting analysis indicates triaxial deformation for positive-parity bands, while negative-parity bands show axial symmetry, similar to Zr. This reveals a shape coexistence in neutron-rich Nb nuclei.

   nucl-exnucl-thPRC(2026)·2 citations
3. 03*

   Neutrino non-radiative decay in matter: constraints and prospects

   Pilar Iváñez-Ballesteros (APC, Paris)🇫🇷 · M. Cristina Volpe (APC, Paris)🇫🇷

   Neutrinos, being massive, can decay. A heavier neutrino could decay into a lighter one and a massless scalar or pseudoscalar boson, such as the Majoron. Two-body non-radiative decay could occur in dense matter, such as in the inner dense regions of a core-collapse supernova. We first derive novel bounds on neutrino-Majoron couplings using the spectral distortions induced by neutrino non-radiative two-body decay in matter, and two-dimensional likelihood analyses of the 24 ${\bar{\nu }}_e$ events from SN1987A. We then explore the prospects of neutrino-Majoron couplings from a future galactic core-collapse supernova, leaving either a neutron star or a black-hole. To this aim, we use information from detailed one-dimensional supernova simulations. We consider the supernova neutrino signal associated with inverse-beta decay in the upcoming JUNO and Hyper-Kamiokande detectors, with neutrino-argon scattering in DUNE, or with coherent neutrino-nucleus scattering in the DARWIN experiment. In a full 3$\nu$ framework, based on the spectral distortions induced by neutrino decay in matter, we perform two-dimensional likelihood analyses and provide prospects for the limits on neutrino-Majoron couplings. Our results show that the observation of a future supernova will significantly improve on the current bounds, in particular from SN1987A and neutrinoless double-beta decay. Finally, we explore the impact of neutrino decay in matter on the diffuse supernova neutrino background formed by past supernova explosions. We show for the first time that the effects on black-hole contributions are important and modify the DSNB number of events by several tens of percent in Hyper-Kamiokande.

   ↳ hep-phastro-ph.SRhep-exnucl-ex+1JCAP(2026)·4 citations
4. 04*

   Two-neutrino $\beta \beta$ decay to excited states at next-to-leading order

   Daniel Castillo🇪🇸 · Dorian Frycz🇪🇸 · Beatriz Benavente🇪🇸 · Javier Menéndez🇪🇸

   We study two-neutrino double-beta decay ($2\nu \beta \beta$) into first-excited $0_2^{+}$ states of nuclei used in $\beta \beta$ decay experiments, including ${}^{76}$Ge, ${}^{82}$Se, ${}^{130}$Te, and ${}^{136}$Xe. We calculate the corresponding nuclear matrix elements (NMEs) within the nuclear shell model, using various Hamiltonians that describe well the spectroscopy of the initial and final nuclei. We evaluate the next-to-leading order (NLO) long-range NMEs recently introduced within chiral effective field theory, keeping three terms in the expansion of the energy denominator. In most cases, NLO contributions to the half-life are below 5%, but they can significantly increase due to cancellations in the leading-order Gamow-Teller NME. A detailed analysis in terms of nuclear deformation, including triaxiality, indicates that larger deformation differences between the initial and final states generally lead to smaller NMEs, but the seniority structure of the states also plays a relevant role. The lower range of our predicted half-lives, with uncertainties dominated by the nuclear Hamiltonian used, are slightly longer than the current experimental limit in ${}^{76}$Ge and consistent with the very recent half-life indication in ${}^{82}$Se.

   ↳ nucl-thhep-exhep-phnucl-exPLB(2026)·3 citations
5. 05*

   Constraining neutron-proton effective mass splitting through nuclear giant dipole resonance within transport approach

   Yi-Dan Song🇨🇳 · Min-Si Luo🇨🇳 · Rui Wang🇮🇹 · Zhen Zhang🇨🇳 · Yu-Gang Ma🇨🇳

   Based on the Boltzmann-Uehling-Uhlenbeck equation, we investigate the effects of the isovector nucleon effective mass $m_{v,0}^{\ast }$ and the in-medium nucleon-nucleon cross section ${\sigma }^{\ast }$ on the isovector giant dipole resonance~(IVGDR) in ${}^{208}\mathrm{Pb}$, employing a set of representative Skyrme energy density functionals. We find that the energy-weighted sum rule $m_1$ of the IVGDR is highly sensitive to $m_{v,0}^{\ast }$ and only mildly dependent on ${\sigma }^{\ast }$, while the width $\Gamma$ of the IVGDR is primarily governed by ${\sigma }^{\ast }$ with a moderate sensitivity to $m_{v,0}^{\ast }$. From a Bayesian analysis of both $m_1$ and $\Gamma$, we infer the isovector effective mass $m_{v,0}^{\ast }/m$ = $0.731_{-0.023}^{+0.027}$, where $m$ is the bare nucleon mass. Furthermore, by incorporating the isoscalar effective mass $m_{s,0}^{\ast }/m=0.820\pm 0.030$, extracted from the isoscalar giant quadrupole resonance in ${}^{208}\mathrm{Pb}$, the linear neutron-proton effective mass splitting coefficient at saturation density ${\rho }_0$ is determined to be $\Delta m_1^{\ast }({\rho }_0)/m=0.200_{-0.094}^{+0.101}$.

   ↳ nucl-thnucl-exPRC(2025)·3 citations
6. 06*

   Study of thorium in hypersonic gas jets: Ionization potentials of Th and Th${}^{+}$

   A. Claessens🇧🇪 · F. Ivandikov🇧🇪 · M. Brasseur · A. Dragoun · Ch. E. Düllmann🇩🇪 · R. Ferrer🇧🇪 · Yu. Kudryavtsev🇧🇪 · P. Palmeri · P. Quinet · S. Raeder🇩🇪 · D. Renisch🇩🇪 · P. Van den Bergh🇧🇪 · P. Van Duppen🇧🇪

   Laser ionization spectroscopy was performed on both neutral and singly ionized ${}^{232}$Th with the aim of identifying the nuclear-clock isomer in the singly charged ionic state of ${}^{229}$Th. A search for an efficient laser ionization scheme of ${}^{232}$Th${}^{+}$ was conducted in an argon-filled gas cell. This revealed a congested spectrum due to collisional quenching effects and the presence of several auto-ionizing states, one of which has a laser ionization efficiency of at least $1.2\%$. Using a threshold approach, the second ionization potential was determined to be $12.300(9)$eV. The subsequent study on atomic ${}^{232}$Th validated the threshold approach. Conducting spectroscopy in a hypersonic gas jet, suppressed the gas-collision-induced quenching, revealing a Rydberg series that converges to the first ionization potential, determined to be $6.306879(14)$eV. The gas jet also cools down the thorium, allowing for high-resolution laser spectroscopy with a resolution of $240(30)$MHz. Using the Multiconfigurational Dirac-Hartree-Fock (MCDHF) method, the ionization potentials were computed, showing a relative difference of 0.06\% and 0.19\% between theory and our experimental values for the ionization potentials of Th and Th${}^{+}$ respectively. Further calculations using a pseudo-relativistic Hartree-Fock method reveal strong mixing in the used intermediate state at $26113.27$cm${}^{-1}$ of Th. A dedicated fast-extraction gas cell with ${}^{233}$U recoil sources was used to study ${}^{229}$Th${}^{+}$ but no photo-ionization signal could be observed.

   ↳ physics.atom-phnucl-exPRA(2025)·1 citation

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.