Mon·Feb 10, 2025Monday·February 10, 2025

1. 01*

   High-precision direct decay energy measurements of the electron-capture decay of ${}^{97}$Tc

   Zhuang Ge🇫🇮 · Tommi Eronen🇫🇮 · Vasile Alin Sevestrean🇷🇴 · Marlom Ramalho🇫🇮 · Ovidiu Nitescu🇷🇴 · Stefan Ghinescu🇷🇴 · Sabin Stoica🇷🇴 · Jouni Suhonen🇫🇮 · Antoine de Roubin🇧🇪 · Dmitrii Nesterenko🇫🇮 · Anu Kankainen🇫🇮 · Pauline Ascher🇫🇷 and 18 other authors

   A direct measurement of the ground-state-to-ground-state electron-capture decay $Q$ ($Q_{\mathrm{EC}}$) value of ${}^{97}$Tc has been conducted employing the high resolving power phase-imaging ion-cyclotron-resonance technique with the double Penning trap mass spectrometer JYFLTRAP. The resulting $Q_{\mathrm{EC}}$ value for ${}^{97}$Tc is 324.82(21) keV, exhibiting a precision approximately 19 times higher than the value adopted in the newest Atomic Mass Evaluation (AME2020) and differing by 1.2$\sigma$. Furthermore, by combining this refined $Q$ value with nuclear energy-level data for the decay-daughter ${}^{97}$Mo, a potential ultra-low Q-value transition, possibly of allowed type, ${}^{97}$Tc (9/2${}^{+}$, ground state) $\to$ ${}^{97}$Mo${}^{\ast }$ (320(1) keV), was evaluated for future long-term neutrino-mass determination experiments. The ground-state-to-excited-state electron-capture decay $Q$ value ($Q_{\mathrm{EC}}^{\ast }$) of this transition was determined to be 4.8(10) keV, confirming it to be energetically allowed with a confidence level of exceeding 4$\sigma$. The captures of electrons occupying the L and higher shells for this transition are energetically allowed, giving a value of 2.0(10) keV for the closest distance of $Q_{\mathrm{EC}}^{\ast }$ to the allowed binding energy of the L1 shell. To predict partial half-lives and energy-release distributions for this transition, the atomic self-consistent many-electron Dirac--Hartree--Fock--Slater method and the nuclear shell model have been employed. Dominant correction terms such as exchange and overlap corrections, as well as shake-up and shake-off effects, were included in the final results. Moreover, the normalized distribution of released energy in the electron-capture decay of ${}^{97}$Tc to excited states of ${}^{97}$Mo, is compared with that of ${}^{163}$Ho, which is being used for electron-neutrino-mass determination.

   nucl-exnucl-thPRC(2025)·2 citations
2. 02*

   Investigating effects of the electrical conductivity of QCD matter on charge-dependent directed flow

   Nicholas J. Benoit🇯🇵 · Takahiro Miyoshi🇯🇵 · Chiho Nonaka🇯🇵 · Hiroyuki R. Takahashi🇯🇵

   Charge dependent directed flow is an important observable of electromagnetic fields in relativistic heavy-ion collisions. We demonstrate how the difference in charge dependent directed flows between protons and antiprotons is sensitive to the resistivity, inverse of quark-gluon plasma's electric conductivity, over different collision centralities. Our model numerically solves the 3+1D relativistic resistive magneto-hydrodynamic (RRMHD) equations, assuming the electric conductivity to be a scalar. For this work, we focus on symmetric Au + Au collisions at the top RHIC energy of $\sqrt{s}=200$ GeV. We illustrate the time evolution of the electromagnetic fields in our model and connect that to the charge dependent directed flow results. Our results highlight the importance of modeling quark-gluon plasma's electric conductivity for charge dependent observables in relativistic heavy-ion collisions.

   ↳ nucl-thhep-exhep-phnucl-exPRC(2025)·6 citations
3. 03*

   Probing properties of nuclear spin-orbit interaction with nucleon spin polarization in intermediate-energy heavy-ion collisions

   Jun Xu🇨🇳

   The nucleon spin polarization perpendicular to the reaction plane ($P_y$) and along the beam direction ($P_z$) in Au+Au collisions at the beam energy of 100A MeV with different nuclear spin-orbit interactions has been studied based on a spin- and isospin-dependent Boltzmann-Uehling-Uhlenbeck (SIBUU) transport model. While the spin polarization is weaker with a weaker nuclear spin-orbit coupling as intuitively expected, a density-dependent nuclear spin-orbit coupling enhances the $P_y$ at large rapidities and leads to a less negative or large $P_y$ at high transverse momenta. The difference in the $P_y$ of free neutrons and protons at midrapidities and at small transverse momenta is sensitive to the isospin dependence of the nuclear spin-orbit interaction. While the $P_z$ is also affected by the properties of nuclear spin-orbit interaction in some sense, the behavior of the $P_y$ serves as a good probe of the strength, density dependence, and isospin dependence of nuclear spin-orbit interaction.

   ↳ nucl-thhep-exnucl-exPRC(2025)·2 citations
4. 04*

   A glimpse into an effective world

   Luigi Coraggio🇮🇹 · Nunzio Itaco🇮🇹

   Our contribution aims to celebrate the immeasurable contribution that Tom Kuo has provided to the understanding of the structure of atomic nuclei, and also of the infinite nuclear matter, in terms of the fundamental principles governing the realistic nuclear potential. The authors want to testify Tom Kuo's heritage and impact on their approach to the study of nuclear systems by reviewing some recent findings on the role of the two-body component of shell-model effective $\beta$-decay operators. The focus is spotted on the so-called Pauli-blocking effect, that plays a non-negligible role in nuclei characterized by a large number of valence nucleons.

   ↳ nucl-thnucl-exIJMPE(2025)·1 citation
5. 05*

   Integration Concept of the CBM Micro Vertex Detector

   Franz Matejcek🇩🇪 · Ali-Murteza Altingun🇫🇷 · Julio Andary🇩🇪 · Benedict Arnoldi-Meadows🇩🇪 · Jerome Baudot🇫🇷 · Gregory Bertolone🇫🇷 · Auguste Besson🇫🇷 · Norbert Bialas🇩🇪 · Christopher Braun🇩🇪 · Roma Bugiel🇫🇷 · Gilles Claus🇫🇷 · Claude Colledani🇫🇷 and 26 other authors

   The Micro Vertex Detector (MVD) is the most upstream detector of the fixed-target Compressed Baryonic Matter Experiment (CBM) at the future Facility for Antiproton and Ion Research (FAIR). It enables high-precision low-momentum tracking in direct proximity of the target. Reaching the stringent requirements for the MVD, a material budget of~$0.3-0.5\%X_0$ per layer, operating the dedicated CMOS MAPS~(`MIMOSIS') in the target vacuum, the strong magnetic dipole field, and a harsh radiation environment~(5\,Mrad, $7\times 10^{13}{n}_{\text{eq}}/{\text{cm}}^2$ per CBM year), poses an unprecedented integration challenge. In this paper, the integration concept of the detector is be outlined, elaborating on the selection and preparation of materials, assembly procedures, and quality assessment steps in the ongoing preparation of pre-series production and detector commissioning in 2028.

   ↳ physics.ins-dethep-exnucl-exJINST(2025)·2 citations
6. 06*

   Calibration of a $\Delta$E-E telescope based on CeBr${}_3$ scintillator for secondary charged particles measurements in hadron therapy

   L. Gesson🇫🇷 · J. Gross🇫🇷 · C. Mozzi🇫🇷 · C. Reibel🇫🇷 · Ch. Finck🇫🇷 · S. Higueret🇫🇷 · T.D. Le🇩🇪 · E. Traykov🇫🇷 · J.C. Thomas🇫🇷 · N. Arbor🇫🇷 · M. Pullia🇮🇹 · G. Harmant🇫🇷 · M. Vanstalle🇫🇷

   Hadrontherapy is an established cancer treatment method that enables a more localized dose deposition compared to conventional radiotherapy, potentially reducing the dose to surrounding healthy tissues in certain clinical cases. However, a key limitation in current treatment planning lies in the limited experimental data available for the characterization of secondary particles generated by nuclear interactions of the primary beam with tissues, which directly impacts the accuracy of Monte Carlo tools and analytical models used in dose calculations. Indeed, this leads to the adoption of larger safety margins and can limit the use of hadrontherapy for treating certain complex or sensitive tumor locations. This work is part of the context of the characterization of secondary charged particles generated by ion beams in the energy range relevant for particle therapy applications, using a $\Delta E-E$ telescope comprising a CeBr${}_3$ crystal scintillator and a plastic scintillator. The calibration and response of this telescope to ions commonly used in clinical settings is presented in this work, highlighting adherence to Birks' law for accurate energy measurements. This study is the first to optimize a $\Delta E-E$ telescope combining CeBr${}_3$ and plastic scintillators specifically for secondary particle detection in hadrontherapy. It represents an essential step toward the experimental acquisition of nuclear data, enabling accurate measurement and identification of secondary charged particles generated by therapeutic beams in tissue-equivalent materials. The system is designed for use in controlled experimental setups that reproduce clinical conditions, with the goal of improving the predictive accuracy of treatment planning software through enhanced Monte Carlo simulation inputs.

   ↳ physics.ins-detnucl-exphysics.med-phJINST(2026)·0 citations
7. 07*

   Collision energy dependence in heavy ion collisions from nonlinear QCD evolution

   Heikki Mäntysaari🇫🇮 · Björn Schenke🇺🇸 · Chun Shen🇺🇸 · Wenbin Zhao🇺🇸

   We explore the effects of including the energy dependence determined from evolution equations within the color glass condensate framework on observables in ultra-relativistic heavy-ion collisions. This amounts to integrating the JIMWLK evolution equations into the IP-Glasma model, which is then coupled to viscous relativistic hydrodynamics. This methodology allows for a systematic representation of nuclei at specific Bjorken-$x$ values, which are probed at different center-of-mass energies of the collision and rapidities of final state particles. Comparing to the conventional IP-Glasma model, we find significant effects on multiplicity distributions and particle spectra, especially in smaller collision systems at the highest center of mass energies. Our results highlight the importance of incorporating nonlinear QCD evolution in the description of heavy ion collisions at varying center of mass energies, as the precise extraction of transport coefficients will be affected. This work establishes a robust framework for understanding the quark gluon plasma and nuclear structure at high energy, integrating small-$x$ physics into the initial conditions of heavy-ion collisions.

   ↳ nucl-thhep-exhep-phnucl-exPRL(2025)·22 citations

* 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.