Fri·Jan 21, 2022Friday·January 21, 2022

1. 01*

   Ground State Magnetic Dipole Moment of ${}^{40}$Sc

   Robert Powel🇺🇸 · B. Alex Brown🇺🇸 · Jason D. Holt🇨🇦 · Andrew Klose · Kristian König🇺🇸 · Jeremy Lantis🇺🇸 · Kei Minamisono🇺🇸 · Takayuki Miyagi🇨🇦 · Skyy Pineda🇺🇸

   The hyperfine coupling constants of the proton dripline odd-odd ${}^{40}$Sc nucleus were deduced from the hyperfine spectrum of the $3d4s{}^3{\text{D}}_2$\,$\leftrightarrow$\,$3d4p{}^3{\text{F}}_3^{\circ }$ transition in Sc II, measured by the bunched beam collinear laser spectroscopy technique. The ground state magnetic dipole and electric quadrupole moments were determined for the first time as $\mu$\,=\,$+5.57(4)(2){\mu }_N$ and $Q$\,=\,$+42(38)(28)e^2\mathrm{f}{\mathrm{m}}^2$, respectively. The magnetic moment is well reproduced by the additivity rule with magnetic moments of neighboring odd-even nuclei in the vicinity of the doubly-magic ${}^{40}$Ca nucleus. An ab-initio multishell valence-space Hamiltonian was also employed to calculate the magnetic moment of ${}^{40}$Sc, which spans across the $sd$ and $fp$ nuclear shells, where we obtained good agreements.

   nucl-exnucl-thPRC(2022)·8 citations
2. 02*

   Parton distributions of light quarks and antiquarks in the proton

   Lei Chang🇨🇳 · Fei Gao🇨🇳 · Craig D. Roberts🇨🇳

   An algebraic Ansatz for the proton's Poincaré-covariant wave function, which includes both scalar and pseudovector diquark correlations, is used to calculate proton valence, sea, and glue distribution functions (DFs). Regarding contemporary data, a material pseudovector diquark component in the proton is necessary for an explanation of the neutron-proton structure function ratio; and a modest Pauli blocking effect in the gluon splitting function is sufficient to explain the proton's light-quark antimatter asymmetry. In comparison with pion DFs, the light-front momentum fractions carried by all identifiable parton classes are the same; on the other hand, the higher moments are different. Understanding these features may provide insights that explain distinctions between Nambu-Goldstone bosons and seemingly less complex hadrons.

   ↳ hep-phhep-exhep-latnucl-ex+1PLB(2022)·38 citations
3. 03*

   A feasibility study of extruded plastic scintillator embedding WLS fiber for AMoRE-II muon veto

   J. W. Seo · W. T. Kim · Y. D. Kim · H. Y. Lee · J. Lee · M. H. Lee · P. B. Nyanda · E. S. Yi

   AMoRE-II is the second phase of the Advanced Molybdenum-based Rare process Experiment aiming to search for the neutrino-less double beta decay of 100Mo isotopes using ~ 200 kg of molybdenum-containing cryogenic detectors. The AMoRE-II needs to keep the background level below 10-5 counts/keV/kg/year with various methods to maximize the sensitivity. One of the methods is to have the experiment be carried out deep underground free from the cosmic ray backgrounds. The AMoRE-II will run at Yemilab with ~ 1,000 m depth. However, even in such a deep underground environment, there are still survived cosmic muons, which can affect the measurement and should be excluded as much as possible. A muon veto detector is necessary to reject muon-induced particles coming to the inner detector where the molybdate cryogenic detectors are located. We have studied the possibility of using an extruded plastic scintillator and wavelength shifting fiber together with SiPM as a muon veto system. We found that the best configuration is two layers of plastic scintillators (PSs, 150 cm x 25 cm x 1.2 cm) with two WLS fibers per groove, which could separate radiogenic gammas well with muon detection efficiency above 99.4% along the length of the PS. Based on the expected flux from a prototype measurement at a 700 m deep underground, we found that the dead time of the muon veto system for AMoRE-II at the Yemilab with a 1 ms veto window is 0.6% of whole muon events.

   ↳ physics.ins-detastro-ph.IMhep-exnucl-exNucl.Instrum.Meth.A(2022)·5 citations
4. 04*

   Sub-barrier fusion reactions

   K. Hagino🇯🇵

   The concept of compound nucleus was proposed by Niels Bohr in 1936 to explain narrow resonances observed in scattering of a slow neutron off atomic nuclei. A compound nucleus is a metastable state with a long lifetime, in which all the degrees of freedom are in a sort of thermal equilibrium. Fusion reactions are defined as reactions to form such compound nucleus by merging two atomic nuclei. Here a short description of heavy-ion fusion reactions at energies close the Coulomb barrier is presented. This includes: (i) an overview of a fusion process, (ii) a strong interplay between nuclear structure and fusion, (iii) fusion and multi-dimensional/multi-particle quantum tunneling, and (iv) fusion for superheavy elements.

   ↳ nucl-thnucl-ex5 citations
5. 05*

   Fluidity of the system produced in relativistic pp and heavy-ion collisions: Hadron resonance gas model approach

   Ronald Scaria🇮🇳 · Dushmanta Sahu🇮🇳 · Captain R. Singh🇮🇳 · Raghunath Sahoo🇮🇳 · Jan-e Alam🇮🇳

   We have estimated the dimensionless parameters such as Reynolds number ($Re$), Knudsen number ($Kn$) and Mach number ($Ma$) for a multi-hadron system by using the excluded volume hadron resonance gas (EVHRG) model along with Hagedorn mass spectrum to include higher resonances in the system. The size dependence of these parameters indicate that the system formed in proton+proton collisions may achieve thermal equilibrium making it unsuitable as a benchmark to analyze the properties of the system produced in heavy ion collisions at similar energies. While the magnitude of $Kn$ can be used to study the degree of thermalization and applicability of inviscid hydrodynamics, the variations of $Re$ and $Ma$ with temperature ($T$) and baryonic chemical potential (${\mu }_B$) assist to understand the change in the nature of the flow in the system. Indeed the nature of flow changes from laminar to turbulent as $Re$ increases and the system is characterized as incompressible for low $Ma(<<1)$ and compressible for larger $Ma$. $Ma$ can also be used to understand whether the flow is subsonic or supersonic.

   ↳ hep-phhep-exnucl-exnucl-thEPJA(2023)·9 citations
6. 06*

   Calculations of neutron fluxes and isotope conversion rates in a thorium-fuelled MYRRHA reactor, using GEANT4 and MCNPX, Nuclear Engineering and Design

   Asiya Rummana🇴🇲 · Roger John Barlow🇬🇧 · Syed Mohammad Saad🇴🇲

   Neutronics calculations have been performed of the MYRRHA ADS Reactor with a thorium-based fuel mixture, using the simulation programs MCNPX (Waters, 2002) and Geant4 (Agostinelli, 2003). Thorium is often considered for ADS systems, and this is the first evaluation of the possibilities for thorium based fuels using a reactor design which has been developed in detail. It also extends the application of the widely-used Geant4 program to the geometry of MYRRHA and to thorium. An asymptotic 232Th/233U mixture is considered, together with the standard MOX fuel and a possible 232Th/MOX starter. Neutron fluxes and spectra are calculated at several regions in the core: fuel cells, IPS cells and the two (Mo and Ac) isotope production cells. These are then used for simple calculations of the fuel evolution and of the potential for the incineration of minor actinide waste. Results from the two programs agree and support each other and show that the thorium fuel is viable, and has good evolution/breeding properties, and that minor actinide incineration, though it will not take place on a significant scale, will be demonstrable.

   ↳ physics.acc-phnucl-exNucl.Eng.Des.(2022)·2 citations
7. 07*

   Unified Explanation of the Anomalies in Semi-Leptonic $B$ decays and the $W$ Mass

   Marcel Algueró🇪🇸 · Andreas Crivellin🇨🇭 · Claudio Andrea Manzari🇨🇭 · Joaquim Matias🇪🇸

   The discrepancies between the measurements of rare (semi-)leptonic $B$ decays and the corresponding Standard Model predictions point convincingly towards the existence of new physics for which a heavy neutral gauge boson ($Z^{\prime }$) is a prime candidate. However, the effect of the mixing of the $Z^{\prime }$ with the SM $Z$, even though it cannot be avoided by any symmetry, is usually assumed to be small and thus neglected in phenomenological analyses. In this letter we point out that a mixing of the naturally expected size leads to lepton flavour universal contributions, providing a very good fit to $B$ data. Furthermore, the global electroweak fit is affected by $Z-Z^{\prime }$ mixing where the tension in the $W$ mass, recently confirmed and strengthened by the CDF measurement, prefers a non-zero value of it. We find that a $Z^{\prime }$ boson with a mass between $\approx 1-5\mathrm{TeV}$ can provide a unified explanations of the $B$ anomalies and the $W$ mass. This strongly suggests that the breaking of the new gauge symmetry giving raise to the $Z^{\prime }$ boson is linked to electroweak symmetry breaking with intriguing consequences for model building.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2022)·36 citations
8. 08*

   On the Stability of Superheavy Nuclei

   Krzysztof Pomorski🇵🇱 · Artur Dobrowolski🇵🇱 · Bozena Nerlo-Pomorska🇵🇱 · Michal Warda🇵🇱 · Johann Bartel🇫🇷 · Zhigang Xiao🇨🇳 · Yongjing Chen🇨🇳 · Lile Liu🇨🇳 · Jun-Long Tian🇨🇳 · Xinyue Diao🇨🇳

   Potential energy surfaces of even-even superheavy nuclei are evaluated within the macroscopic-microscopic approximation. A very rapidly converging analytical Fourier-type shape parametrization is used to describe nuclear shapes throughout the periodic table, including those of fissioning nuclei. The Lublin Strasbourg Drop and another effective liquid-drop type mass formula are used to determine the macroscopic part of nuclear energy. The Yukawa-folded single-particle potential, the Strutinsky shell-correction method, and the BCS approximation for including pairing correlations are used to obtain microscopic energy corrections. The evaluated nuclear binding energies, fission-barrier heights, and Q-alpha energies show a relatively good agreement with the experimental data. A simple one-dimensional WKB model a la Swiatecki is used to estimate spontaneous fission lifetimes, while alpha-decay probabilities are obtained within a Gamow-type model.

   ↳ nucl-thnucl-exEPJA(2022)·17 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.