Thu·Mar 20, 2025Thursday·March 20, 2025

1. 01*

   NuPECC Long Range Plan 2024 for European Nuclear Physics

   NuPECC (Nuclear Physics European Collaboration Committee)

   The Nuclear Physics European Collaboration Committee ( NuPECC, http://nupecc.org/ ) hosted by the European Science Foundation represents today a large nuclear physics community from 23 countries, 3 ESFRI (European Strategy Forum for Research Infrastructures) nuclear physics infrastructures and ECT* (European Centre for Theoretical Studies in Nuclear Physics and Related Areas), as well as from 4 associated members and 10 observers. As stated in the NuPECC Terms of Reference one of the major objectives of the Committee is: "on a regular basis, the Committee shall organise a consultation of the community leading to the definition and publication of a Long Range Plan (LRP) of European nuclear physics". To this end, NuPECC has in the past produced five LRPs: in November 1991, December 1997, April 2004, December 2010, and November 2017. The LRP, being the unique document covering the whole nuclear physics landscape in Europe, identifies opportunities and priorities for nuclear science in Europe and provides national funding agencies, ESFRI, and the European Commission with a framework for coordinated advances in nuclear science. It serves also as a reference document for the strategic plans for nuclear physics in the European countries.

   nucl-exnucl-th12 citations
2. 02*

   Measurement of SiPM Dark Currents and Annealing Recovery for Fluences Expected in ePIC Calorimeters at the Electron-Ion Collider

   Jiajun Huang🇺🇸 · Sean Preins🇺🇸 · Ryan Tsiao🇺🇸 · Miguel Rodriguez🇺🇸 · Barak Schmookler🇺🇸 · Miguel Arratia🇺🇸

   Silicon photomultipliers (SiPMs) will be used to read out all calorimeters in the ePIC experiment at the Electron-Ion Collider (EIC). A thorough characterization of the radiation damage expected for SiPMs under anticipated EIC fluences is essential for accurate simulations, detector design, and effective operational strategies. In this study, we evaluate radiation damage for the specific SiPM models chosen for ePIC across the complete fluence range anticipated at the EIC, $10^8$ to $10^{12}$ 1-MeV $n_{\mathrm{eq}}$/cm${}^2$ per year, depending on the calorimeter location. The SiPMs were irradiated using a 64 MeV proton beam provided by the University of California, Davis 76" Cyclotron. We measured the SiPM dark-current as a function of fluence and bias voltage and investigated the effectiveness of high-temperature annealing to recover radiation damage. These results provide a comprehensive reference for the design, simulation, and operational planning of all ePIC calorimeter systems.

   ↳ physics.ins-dethep-exnucl-ex3 citations
3. 03*

   Study of event and particle selection effects on elliptic flow background at the isobar experiments based on AMPT model

   Yu Wang🇨🇳 · Hua Pei🇨🇳

   Measurement of the Chiral Magnetic Effect (CME) has been a popular topic of high-energy nuclear physics in the last decade. The flow correlation $\gamma$ between charged hadron pairs of the same and opposite charges and their difference $\Delta \gamma$ were measured to separate the CME-driven signal from the collective flow background especially second-order elliptic $v_2$. The STAR experiment have stepped further to the isobar experiment to compare $\gamma$ and $\Delta \gamma$ between Ru+Ru and Zr+Zr ~\cite{PhysRevC.105.014901}, which were theoretically expected to produce the same elliptic flow background but different CME signals. However, the measured flow backgrounds also differ between Ru+Ru and Zr+Zr, indicating more fine-tuning of RP and centrality definition necessary. This analysis applied the AMPT model~\cite{PhysRevC.72.064901} to simulate the same collision system and energy as the STAR isobar experiment. Since the AMPT model does not include magnetic field effects, we expect comparing its output between Ru+Ru and Zr+Zr collision systems can provide an insight of the possible bias of flow background definition, and help improve the measurement of CME signal in real experiments. Multiple combinations of centrality and flow definition were chosen to study how the $v_2$ and their difference would be affected, especially by varying the particles selection of charge versus neutral properties and broadening (pseudo-)rapidity regions, while STAR CME work relied on charged-only particles at central rapidity.

   ↳ nucl-thnucl-ex2 citations
4. 04*

   Nuclear Physics under the low-energy, high intensity frontier

   C.-J. Yang🇷🇴 · V. Horny · D. Doria · K. Spohr

   Despite numerous achievements and recent progress, nuclear physics is often (wrongly) considered an old field of research nowadays. However, developments in theoretical frameworks and reliable experimental techniques have made the field mature enough to explore many new frontiers. In this regard, extending existing knowledge to an emerging field of physics -- where particles interact with a relatively low-energy but high intensity field (intense enough so that multi-particle processes become comparable or more important than one-to-one processes) -- can lead to exciting discoveries. Investigations can be realized under a highly time-compressed beam source (e.g., particle sources generated by laser-matter interaction using high-power laser systems). Here we focus on a new scheme, where high-power laser systems are exploited as a driver to generate energetic ($\gamma$-ray) photons. Together with additional low-energy photons provided by a second, less intense laser, a multi-photon absorption scheme enables a very attainable manipulation of nuclear transitions including isomer pumping and depletion.

   ↳ nucl-thnucl-exProc. SPIE 13535, Research Using Extreme …·1 citation
5. 05*

   Ultra-cold neutron simulation framework for the free neutron lifetime experiment $\tau$SPECT

   Julian Auler · Utkarsh Bajpai · Martin Engler · Viktoria Ermuth · Martin Fertl🇩🇪 · Konrad Franz · Werner Heil🇩🇪 · Simon Kaufmann🇩🇪 · Bernhard Lauss🇨🇭 · Niklas Pfeifer · Dieter Ries🇨🇭 · Sylvain Vanneste · Noah Yazdandoost🇨🇭

   The precise determination of the free neutron lifetime is of great significance in modern precision physics. This key observable is linked to the mixing of up and down quarks via the Cabibbo-Kobayashi-Maskawa matrix element $V_{ud}$, and the abundance of primordial elements after the Big-Bang Nucleosynthesis. However, the two leading measurement techniques for the neutron lifetime currently yield incompatible results, a discrepancy referred to as the neutron lifetime puzzle. To address the systematic uncertainties arising from neutron interactions with material walls, the $\tau$SPECT experiment employs a fully magnetic trap for ultra-cold neutrons (UCNs). UCNs are extremely low-energy neutrons with typical velocities below $8\text{m/s}$, which can be manipulated using magnetic fields, gravity, and suitable material guides, whose surface can reflect them at any angle of incidence. To precisely study and characterize UCN behavior during production, guidance, storage, and detection in $\tau$SPECT, we have developed a dedicated simulation framework. This framework is built upon the externally developed UCN Monte Carlo software package PENTrack and is enhanced with two companion tools: one for flexible and parametrizable upstream configuration of PENTrack such that the simulation's input settings can be adjusted to reproduce the experimental observations. The second package is used for analyzing, visualizing, and animating simulation data. The simulation results align well with experimental data obtained with $\tau$SPECT at the Paul Scherrer Institute and serve as a powerful resource for identifying systematic uncertainties and guiding future improvements to the current experimental setup.

   ↳ physics.ins-detnucl-exEPJA(2025)·1 citation
6. 06*

   Seven-dimensional Trajectory Reconstruction for VAMOS++

   M. Rejmund🇫🇷 · A. Lemasson🇫🇷

   The VAMOS++ magnetic spectrometer is characterized by a large angular and momentum acceptance and highly non-linear ion optics properties requiring the use of software ion trajectory reconstruction methods to measure the ion magnetic rigidity and the trajectory length between the beam interaction point and the focal plane of the spectrometer. Standard measurements, involving the use of a thin target and a narrow beam spot, allow the assumption of a point-like beam interaction volume for ion trajectory reconstruction. However, this represents a limitation for the case of large beam spot size or extended gaseous target volume. To overcome this restriction, a seven-dimensional reconstruction method incorporating the reaction position coordinates was developed, making use of artificial deep neural networks. The neural networks were trained on a theoretical dataset generated by standard magnetic ray-tracing code. Future application to a voluminous gas target, necessitating the explicit inclusion of the three-dimensional position of the beam interaction point within the target in the trajectory reconstruction method, is discussed. The performances of the new method are presented along with a comparison of mass resolution obtained with previously reported model for the case of thin-target experimental data.

   ↳ physics.ins-detcs.LGnucl-exNucl.Instrum.Meth.A(2025)·2 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.