Thu·Sep 8, 2022Thursday·September 8, 2022

1. 01*

   First observation of cyclotron radiation from MeV-scale ${\mathrm{e}}^{pm}$ following nuclear beta decay

   W. Byron🇺🇸 · H. Harrington🇺🇸 · R. J. Taylor · W. DeGraw🇺🇸 · N. Buzinsky🇺🇸 · B. Dodson🇺🇸 · M. Fertl🇩🇪 · A. Garcia🇺🇸 · G. Garvey🇺🇸 · B. Graner🇺🇸 · M. Guigue🇫🇷 · L. Hayen🇺🇸 and 21 other authors

   We present an apparatus for detection of cyclotron radiation that allows a frequency-based beta energy determination in the 5 keV to 5 MeV range, characteristic of nuclear beta decays. The cyclotron frequency of the radiating beta particles in a magnetic field is used to determine the beta energy precisely. Our work establishes the foundation to apply the cyclotron radiation emission spectroscopy (CRES) technique, developed by the Project 8 collaboration, far beyond the 18-keV tritium endpoint region. We report initial measurements of beta^-s from 6He and beta^+s from 19Ne decays to demonstrate the broadband response of our detection system and assess potential systematic uncertainties for beta spectroscopy over the full (MeV) energy range. This work is an important benchmark for the practical application of the CRES technique to a variety of nuclei, in particular, opening its reach to searches for evidence of new physics beyond the TeV scale via precision beta-decay measurements.

   nucl-exPRL(2023)·24 citations
2. 02*

   Differential cross-section measurements for neutron-induced $\alpha$ production reactions on carbon across neutron energy range of 6.2 to 76 MeV

   Longxiang Liu · Kang Sun🇨🇳 · Han Yi🇨🇳 · Fei Lu🇨🇳 · Danyang Pang🇨🇳 · Hongwei Wang🇨🇳 · Gongtao Fan🇨🇳 · Xiguang Cao🇨🇳 · Longlong Song🇨🇳 · Suyalatu Zhang🇨🇳 · Dexin Wang · Xinxiang Li🇨🇳 and 15 other authors

   Angle-differential cross sections for neutron-induced $\alpha$ production in carbon were determined at thirty discrete neutron energy levels ranging from 6.2 to 76 MeV at the Back-n white neutron source of the China Spallation Neutron Source. Utilizing the $\Delta E-E$ telescopes within the Light-charged Particle Detector Array spanning angular measurements from 24.5{\deg}to 155.5{\deg} in the laboratory frame, the ${}^{12}C(n,\alpha )x$ reaction cross sections were obtained. These experimental findings exhibit a strong concordance with prior results and have been benchmarked against theoretical estimates from codes such as TALYS, Geant4, and assessments from the ENDF/B-VIII.0 database. Remarkably, distinct resonance-like features were observed at neutron energies of 13.7, 22.4, 29.5, and 61.8 MeV, marking their first-time identification in the literature.Furthermore, a comparative analysis involving the theoretical Distorted Wave Born Approximation was conducted.

   nucl-ex0 citations
3. 03*

   First direct limit on the 334 keV resonance strength in the ${}^{22}$Ne({\alpha},{\gamma})${}^{26}$Mg reaction

   D. Piatti🇮🇹 · E. Masha🇮🇹 · M. Aliotta🇬🇧 · J. Balibrea-Correa🇪🇸 · F. Barile🇮🇹 · D. Bemmerer🇩🇪 · A. Best🇮🇹 · A. Boeltzig🇮🇹 · C. Broggini🇮🇹 · C. G. Bruno🇬🇧 · A. Caciolli🇮🇹 · F. Cavanna🇺🇸 and 35 other authors

   In stars, the fusion of ${}^{22}$Ne and ${}^4$He may produce either ${}^{25}$Mg, with the emission of a neutron, or ${}^{26}$Mg and a $\gamma$ ray. At high temperature, the ($\alpha ,n$) channel dominates, while at low temperature, it is energetically hampered. The rate of its competitor, the ${}^{22}$Ne($\alpha$,$\gamma$)${}^{26}$Mg reaction, and, hence, the minimum temperature for the ($\alpha ,n$) dominance, are controlled by many nuclear resonances. The strengths of these resonances have hitherto been studied only indirectly. The present work aims to directly measure the total strength of the resonance at $E$_{r}$=$334keV (corresponding to $E$_{x}$=$10949keV in ${}^{26}$Mg). The data reported here have been obtained using high intensity ${}^4$He${}^{+}$ beam from the INFN LUNA 400 kV underground accelerator, a windowless, recirculating, 99.9% isotopically enriched ${}^{22}$Ne gas target, and a 4$\pi$ bismuth germanate summing $\gamma$-ray detector. The ultra-low background rate of less than 0.5 counts/day was determined using 67 days of no-beam data and 7 days of ${}^4$He${}^{+}$ beam on an inert argon target. The new high-sensitivity setup allowed to determine the first direct upper limit of 4.0$\times$10${}^{-11}$ eV (at 90% confidence level) for the resonance strength. Finally, the sensitivity of this setup paves the way to study further ${}^{22}$Ne($\alpha$,$\gamma$)${}^{26}$Mg resonances at higher energy.

   nucl-exEPJA(2022)·20 citations
4. 04*

   Comparative study on charge radii and their kinks at magic numbers

   Tomoya Naito🇯🇵 · Tomohiro Oishi🇭🇷 · Hiroyuki Sagawa🇯🇵 · Zhiheng Wang🇺🇸

   Isotope dependences of charge radii, i.e., isotope shifts, calculated by the Skyrme Hartree-Fock, the relativistic mean-field, and the relativistic Hartree-Fock calculations are compared against the experimental data of magic and semimagic nuclei. It is found that the tensor interaction plays a role in reproducing the ``kink'' behavior, irregularity of isotope shifts at the neutron magic number, in the relativistic Hartree-Fock approach. With several Skyrme models, it is found that the kink behavior can be reproduced with the spin-orbit interaction having nonzero isovector channel. The single-particle orbitals near the Fermi energy are crucial to determine the kink size. The effects of the symmetry energy and the pairing interaction are also discussed in relation to the kink behavior.

   ↳ nucl-thnucl-exPRC(2023)·35 citations
5. 05*

   Massive neutron stars with small radii in relativistic mean-field models optimized to nuclear ground states

   Tsuyoshi Miyatsu🇰🇷 · Myung-Ki Cheoun🇰🇷 · Kyungsik Kim🇰🇷 · Koichi Saito🇯🇵

   We present an equation of state (EoS) for neutron stars using the relativistic mean-field model with isoscalar- and isovector-meson mixing. Taking into account the results of the neutron skin thickness, $R_{\mathrm{skin}}$, of ${}^{208}$Pb reported by the PREX collaboration, the dimensionless tidal deformability of a canonical neutron star observed from GW170817, and a $2.6$ $M_{\odot }$ compact star implied by the secondary component of GW190814, a new effective interaction is constructed so as to reproduce the saturation condition of nuclear matter and the ground-state properties of finite, closed-shell nuclei. We find that the neutron star EoS exhibits the rapid stiffening around twice the nuclear saturation density, which is caused by the soft nuclear symmetry energy, $E_{\mathrm{sym}}$. It is also noticeable that the thick $R_{\mathrm{skin}}$ from the PREX-2 experiment can be achieved with the small slope parameter of $E_{\mathrm{sym}}$ stemming from the isoscalar-meson mixing. Thus, we speculate that the secondary component of GW190814 is the heaviest neutron star ever discovered.

   ↳ nucl-thnucl-ex4 citations
6. 06*

   Physics Opportunities in the ORNL Spallation Neutron Source Second Target Station Era

   J. Asaadi🇺🇸 · P.S. Barbeau🇺🇸 · B. Bodur🇺🇸 · A. Bross🇺🇸 · E. Conley🇺🇸 · Y. Efremenko🇺🇸 · M. Febbraro🇺🇸 · A. Galindo-Uribarri🇺🇸 · S. Gardiner🇺🇸 · D. Gonzalez-Diaz🇪🇸 · M.P. Green🇺🇸 · M.R. Heath🇺🇸 and 17 other authors

   The Oak Ridge National Laboratory (ORNL) Spallation Neutron Source (SNS) First Target Station (FTS), used by the COHERENT experiment, provides an intense and extremely high-quality source of pulsed stopped-pion neutrinos, with energies up to about 50 MeV. Upgrades to the SNS are planned, including a Second Target Station (STS), which will approximately double the expected neutrino flux while maintaining quality similar to the FTS source. Furthermore, additional space for ten-tonne scale detectors may be available. We describe here exciting opportunities for neutrino physics, other particle and nuclear physics, and detector development using the FTS and STS neutrino sources.

   ↳ hep-exnucl-exphysics.ins-det17 citations
7. 07*

   Testing the Gallium Anomaly

   Patrick Huber🇺🇸

   We study the online detection by gallium capture of mono-energetic neutrinos produced by a ${}^{51}$Cr radioactive source in a scintillation experiment. We find that cerium-doped gadolinium aluminum gallium garnet (GAGG) is a suitable scintillator which contains about 21% of gallium per weight and has a high mass density and light yield. Combined with a highly efficient light detection system this allows tagging of the subsequent germanium decay and thus a clean distinction of gallium capture and elastic neutrino electron scattering events. With 1.5 tons of scintillator and 10 source runs of 3.4MCi, each, we obtain about 760 gallium capture events with a purity of 85% and 680,000 neutrino electron scattering events, where the latter provide a precise normalization independent of any nuclear physics. This configuration would allow to test the gallium anomaly at more than $5\sigma$ in an independent way.

   ↳ hep-phhep-exnucl-exPRD(2023)·14 citations
8. 08*

   Tetraquark mixing supported by the partial decay widths of two light-meson nonets

   Hungchong Kim🇰🇷 · K. S. Kim🇰🇷

   Recently, the tetraquark mixing framework has been proposed as a possible structure for the two light-meson nonets in the $J^P=0^{+}$ channel, the light nonet composed of $a_0(980)$, $K_0^{\ast }(700)$, $f_0(500)$, $f_0(980)$, and the heavy nonet of $a_0(1450)$, $K_0^{\ast }(1430)$, $f_0(1370)$, $f_0(1500)$. Among various signatures, we report in this work that their partial decay widths collected from various experimental data in Particle Data Group (PDG) can support this mixing scheme also. In particular, we demonstrate that the couplings of the light nonet to two pseudoscalar mesons estimated from the partial widths are consistently stronger than those of the heavy nonet. This consistent feature agrees qualitatively well with the predictions from the tetraquark mixing framework and, therefore, provides supporting evidence for the tetraquark mixing.

   ↳ hep-phhep-exnucl-exnucl-thEPJC(2022)·7 citations
9. 09*

   Free spectator nucleons in ultracentral relativistic heavy-ion collisions as a probe of neutron skin

   Lu-Meng Liu🇨🇳 · Chun-Jian Zhang🇺🇸 · Jun Xu🇨🇳 · Jiangyong Jia🇺🇸 · Guang-Xiong Peng🇨🇳

   Besides the yield ratio of free spectator neutrons produced in ultracentral ${}^{96}$Zr+${}^{96}$Zr to ${}^{96}$Ru+${}^{96}$Ru collisions, we propose that the yield ratio $N_n/N_p$ of free spectator neutrons to protons in a single collision system at RHIC and LHC can be a more sensitive probe of the neutron-skin thickness $\Delta r_{\mathrm{np}}$ and the slope parameter $L$ of the symmetry energy. The idea is demonstrated based on the proton and neutron density distributions of colliding nuclei obtained from Skyrme-Hartree-Fock-Bogolyubov calculations, and a Glauber model that provides information of spectator matter. The final spectator particles are produced from direct emission, clusterization by a minimum spanning tree algorithm or a Wigner function approach, and deexcitation of heavy clusters by GEMINI. A larger $\Delta r_{\mathrm{np}}$ associated with a larger $L$ value increases the isospin asymmetry of spectator matter and thus leads to a larger $N_n/N_p$, especially in ultracentral collisions where the multiplicity of free nucleons are free from the uncertainties of cluster formation and deexcitation. We have further shown that the double ratio of $N_n/N_p$ in isobaric collision systems or in collisions by isotopes helps to cancel the detecting efficiency for protons. Effects from nuclear deformation and electromagnetic excitation are studied, and they are found to be subdominant compared to the expected sensitivity to $\Delta r_{\mathrm{np}}$.

   ↳ nucl-thhep-exnucl-exPRC(2022)·26 citations
10. 10*

    Report of the Topical Group on Neutrino Properties for Snowmass 2021

    Carlo Giunti🇮🇹 · Julieta Gruszko🇺🇸 · Benjamin Jones🇺🇸 · Lisa Kaufman🇺🇸 · Diana Parno🇺🇸 · Andrea Pocar🇺🇸

    Neutrinos are the most elusive among the known elementary particles, because of their feeble interactions with ordinary matter. They are also the most mysterious, because of their tiny masses that suggest a novel mass generating mechanism, their unknown Dirac or Majorana nature, and their big quantum mixing leading to large-amplitude flavor oscillations. This Topical Group focuses on neutrino properties that are not directly investigated in other Topical Groups of the Neutrino Frontier: in particular, the absolute value of the neutrino masses, the Dirac or Majorana nature of neutrinos, their electromagnetic properties, their lifetime, and hypothetical exotic properties.

    ↳ hep-phhep-exnucl-exnucl-th15 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.