Fri·Jul 14, 2023Friday·July 14, 2023

1. 01*

   Measurement of the production branching ratios following nuclear muon capture for palladium isotopes using the in-beam activation method

   M. Niikura🇯🇵 · T. Y. Saito🇯🇵 · T. Matsuzaki🇯🇵 · K. Ishida🇯🇵 · A. Hillier🇬🇧

   Background: The energy distribution of excited states populated by the nuclear muon capture reaction can facilitate an understanding of the reaction mechanism; however, experimental data are fairly sparse. Purpose: We developed a new methodology, called the in-beam activation method, to measure the production probability of residual nuclei by muon capture. For the first application of the new method, we have measured muon-induced activation of five isotopically-enriched palladium targets. Methods: The experiment was conducted at the RIKEN-RAL muon facility of the Rutherford Appleton Facility in the UK. The pulsed muon beam impinged on the palladium targets and gamma rays from the beta and isomeric decays from the reaction residues were measured using high-purity germanium detectors in both the in-beam and offline setups. Results: The production branching ratios of the residual nuclei of muon capture for five palladium isotopes with mass numbers A = 104, 105, 106, 108, and 110 were obtained. The results were compared with a model calculation using the particle and heavy ion transport system (PHITS) code. The model calculation well reproduces the experimental data. Conclusion: For the first time, this study provides experimental data on the distribution of production branching ratios without any theoretical estimation or assumptions in the interpretation of the data analysis

   nucl-exPRC(2024)·10 citations
2. 02*

   What is ab initio?

   R. Machleidt🇺🇸

   Microscopic nuclear theory is based on the tenet that atomic nuclei can be accurately described as collections of point-like nucleons interacting via two- and many-body forces obeying nonrelativistic quantum mechanics -- and the concept of the ab initio approach is to calculate nuclei accordingly. The forces are fixed in free-space scattering and must be accurate. We will critically review the history of this approach from the early beginnings until today. An analysis of current ab initio calculations reveals that some mistakes of history are being repeated today. The ultimate goal of nuclear theory are high-precision ab initio calculations which, as it turns out, may be possible only at the fifths order of the chiral expansion. Thus, for its fulfillment, nuclear theory is still facing an enormous task.

   ↳ nucl-thnucl-exFew Body Syst.(2023)·28 citations
3. 03*

   Instrumental uncertainties in radiative corrections for the MUSE experiment

   L. Li🇺🇸 · S. Strauch🇺🇸 · J. C. Bernauer🇺🇸 · W. J. Briscoe🇺🇸 · A. Christopher Ndukwe🇺🇸 · E. Cline🇺🇸 · D. Cohen🇮🇱 · K. Deiters🇨🇭 · E. J. Downie🇺🇸 · I. P. Fernando🇺🇸 · A. Flannery🇺🇸 · R. Gilman🇺🇸 and 18 other authors

   The MUSE experiment at the Paul Scherrer Institute is measuring elastic lepton-proton scattering cross sections in a four-momentum transfer range from $Q^2$ of approximately 0.002 to 0.08 GeV${}^2$ using positively and negatively charged electrons and muons. The extraction of the Born cross sections from the experimental data requires radiative corrections. Estimates of the instrumental uncertainties in those corrections have been made using the ESEPP event generator. The results depend in particular on the minimum lepton momentum that contributes to the experimental cross section and the fraction of events with hard initial-state radiation that is detected in the MUSE calorimeter and is excluded from the data. These results show that the angular-dependent instrumental uncertainties in radiative corrections to the electron cross section are better than 0.4 % and are negligible for the muon cross section.

   ↳ hep-exnucl-exEPJA(2024)·7 citations
4. 04*

   ${\Omega }^{-}$ production as a probe of equation of state of dense matter near the QCD phase transition in relativistic heavy-ion collisions

   Zhi-Min Wu🇨🇳 · Gao-Chan Yong🇨🇳

   The production of doubly strange hyperon ${\Xi }^{-}$ and trebly strange hyperon ${\Omega }^{-}$ in relativistic Au+Au collisions at $\sqrt{s_{NN}}$ = 4.2 GeV is explored based on a relativistic transport model that is interweaved with hadronic mean-field potentials for heavy-ion collisions. Upon comparison, it appears that relative to the double strangeness observable ${\Xi }^{-}$, the yield and collective flows of the triple strange ${\Omega }^{-}$ exhibit a higher sensitivity to the equation of state (EoS) of dense matter. This characteristic makes the ${\Omega }^{-}$ an essential observable for studying the properties of densely formed matter in relativistic heavy-ion collisions.

   ↳ nucl-thhep-phnucl-exPRC(2024)·1 citation
5. 05*

   Design of a mobile neutron spectrometer for the Laboratori Nazionali del Gran Sasso (LNGS)

   Melih Solmaz🇩🇪 · Klaus Eitel🇩🇪 · Kathrin Valerius🇩🇪 · Matthias Balzer🇩🇪 · Alfredo Ferella🇮🇹 · Francesco Pompa🇮🇹 · Ulrich Pirling🇩🇪 · Denis Tcherniakhovski🇩🇪 · Uwe Oberlack🇩🇪 · Sascha Wüstling🇩🇪

   Environmental neutrons are a source of background for rare event searches (e.g., dark matter direct detection and neutrinoless double beta decay experiments) taking place in deep underground laboratories. The overwhelming majority of these neutrons are produced in the cavern walls by means of intrinsic radioactivity of the rock and concrete. Their flux and spectrum depend on time and location. Precise knowledge of this background is necessary to devise sufficient shielding and veto mechanisms, improving the sensitivity of the neutron-susceptible underground experiments. In this report, we present the design and the expected performance of a mobile neutron detector for the LNGS underground laboratory. The detector is based on capture-gated spectroscopy technique and comprises essentially a stack of plastic scintillator bars wrapped by gadolinium foils. The extensive simulation studies demonstrate that the detector will be capable of measuring ambient neutrons at low flux levels ($\sim$$10^{-6}n/c{\mathrm{m}}^2/s$) at LNGS, where the ambient gamma flux is by about 5 orders of magnitude larger.

   ↳ physics.ins-detastro-ph.IMnucl-exJINST(2023)·2 citations
6. 06*

   The study of hadronic rescattering on $K^{\ast 0}$ resonance yield in baryon-rich QCD matter

   Aswini Kumar Sahoo🇮🇳 · Subhash Singha🇨🇳 · Md. Nasim🇮🇳

   The effect of hadronic rescattering on $K^{\ast 0}$ resonance yield can be studied by measuring $K^{\ast 0}/K$ ratio as a function of centrality or multiplicity. This study investigates how the size of the system and the chemical composition (meson-meson versus meson-baryon interaction) of the matter formed in heavy-ion collisions impact the process of hadronic rescattering. It is shown that existing calculation of $K^{\ast 0}/K$ ratio, which considers the interaction of $K^{\ast 0}$ and $K$ mesons with only light mesons in the hadronic medium (neglecting interactions with baryons), fails to explain the measured $K^{\ast 0}/K$ ratio at RHIC BES energies. To understand the multiplicity dependence of the $K^{\ast 0}/K$ ratio at RHIC BES and SPS energies ($\sqrt{s_{NN}}$ $<$ 20 GeV), the Ultra Relativistic Quantum Molecular Dynamics (UrQMD) model is employed. UrQMD calculations suggest that for a given multiplicity, $K^{\ast 0}/K$ is more suppressed in Au+Au collision at $\sqrt{s_{NN}}$ =7.7 GeV, compared to that in $\sqrt{s_{NN}}$ =200 GeV. This is possibly because of formation different type of QCD medium at 200 GeV and 7.7 GeV, and change in interaction cross-section between hadrons with change in particle type and energy.

   ↳ nucl-thhep-phnucl-exJ.Phys.G(2025)·12 citations
7. 07*

   Fingerprints of the triaxial deformation from energies and $B(E2)$ transition probabilities of $\gamma$-bands in transitional and deformed nuclei

   S.P. Rouoof · Nazira Nazir · S. Jehangir🇮🇳 · G.H. Bhat🇮🇳 · J.A. Sheikh🇮🇳 · N. Rather · S. Frauendorf

   The energies and $B(E2)$ transitions involving the states of the ground- and $\gamma$-bands in thirty transitional and deformed nuclei are calculated using the triaxial projected shell model (TPSM) approach. Systematic good agreement with the existing data substantiates the reliability of the model predictions. The Gamma-rotor version of the collective Bohr Hamiltonian is discussed in order to quantify the classification with respect to the triaxial shape degree of freedom. The pertaining criteria are applied to the TPSM results and the staggering of the energies of the $\gamma$-bands is analyzed in detail. An analog staggering of the intra-$\gamma$ $B(E2,I\to I-2)$ is introduced for the first time. The emergence of the staggering phenomena in the transitions is explained in the terms of interactions between the bands.

   ↳ nucl-thnucl-exEPJA(2024)·26 citations
8. 08*

   Current status and desired accuracy of the isotopic production cross-sections relevant to astrophysics of cosmic rays II. Fluorine to Silicon (and updated LiBeB)

   Yoann Génolini🇫🇷 · David Maurin🇫🇷 · Igor V. Moskalenko🇺🇸 · Michael Unger🇩🇪

   High-precision cosmic-ray data from ongoing and recent past experiments (Voyager, ACE-CRIS, PAMELA, ATIC, CREAM, NUCLEON, AMS-02, CALET, DAMPE) are being released in the tens of MeV/n to multi-TeV/n energy range. Astrophysical and dark matter interpretations of these data are limited by the precision of nuclear production cross-sections. In Paper I, PRC 98, 034611 (2018), we set up a procedure to rank nuclear reactions whose desired measurements will enable us to fully exploit currently available data on CR Li to N ($Z=3-7$) species. Here we extend these rankings to O up to Si nuclei ($Z=8-14$), also updating our results on the LiBeB species. We also highlight how comprehensive new high precision nuclear data, that could e.g. be obtained at the SPS at CERN, would be a game-changer for the determination of key astrophysical quantities (diffusion coefficient, halo size of the Galaxy) and indirect searches for dark matter signatures.

   ↳ astro-ph.HEhep-exnucl-exnucl-thPRC(2024)·19 citations
9. 09*

   Silicon tracker array for RIB experiments at SAMURAI

   A. I. Stefanescu🇷🇴 · V. Panin🇯🇵 · L. Trache🇷🇴 · T. Motobayashi🇯🇵 · H. Otsu🇯🇵 · A. Saastamoinen🇺🇸 · T. Uesaka🇯🇵 · L. Stuhl🇯🇵 · J. Tanaka🇯🇵 · D. Tudor🇷🇴 · I. C. Stefanescu🇷🇴 · A. E. Spiridon🇷🇴 and 40 other authors

   This work describes a silicon tracker system developed for experiments with proton-rich radioactive ion beams at the SAMURAI superconducting spectrometer of RIBF at RIKEN. The system is designed for accurate angular reconstruction and atomic number identification of relativistic heavy ions and protons which are simultaneously produced in reactions motivated by studies of proton capture reactions of interest for nuclear astrophysics. The technical characteristics of the tracking array are described in detail as are its performance in two pilot experiments. The physics justification for such a system is also presented.

   ↳ physics.ins-detastro-ph.IMnucl-exEPJA(2022)·1 citation
10. 10*

    Illuminating early-stage dynamics of heavy-ion collisions through photons at RHIC BES energies

    Chun Shen🇺🇸 · Abel Noble🇨🇦 · Jean-François Paquet🇺🇸 · Björn Schenke🇺🇸 · Charles Gale🇨🇦

    Heavy-ion collisions at $\sqrt{s_{\mathrm{NN}}}\sim 10$ GeV probe the QCD phase diagram at large baryon densities. Because the longitudinal Lorentz contraction is small at these collision energies, understanding the dynamics during the early phase of the collision is essential for the subsequent modeling of the system evolution and for constraining the QGP transport properties at finite baryon densities. Direct photons provide undistorted information on early-stage dynamics. We model relativistic heavy-ion collisions at RHIC Beam Energy Scan energies with a hybrid dynamical approach consisting of a 3D-Glauber initial state followed by viscous hydrodynamics and hadronic transport (MUSIC + UrQMD). The implemented thermal photon emission takes into account the enhancement from finite baryon chemical potentials. We show that direct photon spectra and their anisotropic flow coefficients have a strong sensitivity to the early stage of heavy-ion collisions. Thus, they provide constraints on QGP dynamics complementary to those obtained from hadronic observables.

    ↳ nucl-thhep-phnucl-exPoS(2024)·8 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.