Mon·May 1, 2023Monday·May 1, 2023

1. 01*

   Experimentally constrained ${}^{165,166}\text{Ho}(n,\gamma )$ rates and implications for the $s$ process

   Francesco Pogliano · Ann-Cecilie Larsen · Stephane Goriely · Lionel Siess · Maria Markova · Andreas Görgen · Johannes Heines · Vetle Werner Ingeberg · Robin Grongstad Kjus · Johan Emil Linnestad Larsson · Kevin Ching Wei Li · Elise Malmer Martinsen and 4 other authors

   The $\gamma$-ray strength function and the nuclear level density of ${}^{167}$Ho have been extracted using the Oslo method from a ${}^{164}\text{Dy}(\alpha ,p\gamma {)}^{167}$Ho experiment carried out at the Oslo Cyclotron Laboratory. The level density displays a shape that is compatible with %can be approximated with the constant temperature model in the quasicontinuum, while the strength function shows structures indicating the presence of both a scissors and a pygmy dipole resonance. Using our present results as well as data from a previous ${}^{163}\text{Dy}(\alpha ,p\gamma {)}^{166}$Ho experiment, the ${}^{165}\text{Ho}(n,\gamma )$ and ${}^{166}\text{Ho}(n,\gamma )$ MACS uncertainties have been constrained. The possible influence of the low-lying, long-lived 6~keV isomer ${}^{166}$Ho in the $s$ process is investigated in the context of a 2~$M_{\odot }$, [Fe/H]=-0.5 AGB star. We show that the newly obtained ${}^{165}\text{Ho}(n,\gamma )$ MACS affects the final ${}^{165}$Ho abundance, while the ${}^{166}\text{Ho}(n,\gamma )$ MACS only impacts the enrichment of ${}^{166,167}$Er to a limited degree due to the relatively rapid $\beta$ decay of the thermalized ${}^{166}$Ho at typical $s$-process temperatures.

   nucl-exPRC(2023)·11 citations
2. 02*

   A comprehensive revision of the summation method for the prediction of reactor antineutrino fluxes and spectra

   Lorenzo Perissé🇫🇷 · Anthony Onillon🇫🇷 · Xavier Mougeot🇫🇷 · Matthieu Vivier🇫🇷 · Thierry Lasserre🇫🇷 · Alain Letourneau🇫🇷 · David Lhuillier🇫🇷 · Guillaume Mention🇫🇷

   The summation method for the calculation of reactor ${\bar{\nu }}_e$ fluxes and spectra is methodically revised and improved. For the first time, a complete uncertainty budget accounting for all known effects likely to impact these calculations is proposed. Uncertainties of a few percents at low energies and ranging up to 20% at high energies are obtained on the calculation of a typical reactor ${\bar{\nu }}_e$ spectrum. Although huge improvements have been achieved over the past decade, the quality and incompleteness of the present day evaluated nuclear decay data still limit the accuracy of the calculations and therefore dominate by far these uncertainties. Pushing the $\beta$-decay modeling of the thousands of branches making a reactor ${\bar{\nu }}_e$ spectrum to a high level of details comparatively brings modest changes. In particular, including nuclear structure calculations in the evaluation of the non-unique forbidden transitions gives a smaller impact than anticipated in past studies. Finally, this new modeling is challenged against state-of-the-art predictions and measurements. While a good agreement is observed with the most recent Inverse Beta Decay measurements of reactor ${\bar{\nu }}_e$ fluxes and spectra, it is unable to properly describe the reference aggregate $\beta$ spectra measured at the Institut Laue-Langevin High-Flux reactor in the 80s. This result adds to recent suspicions $\beta$ the reliability of these data and preferentially points toward a misprediction of the ${}^{235}$U ${\bar{\nu }}_e$ spectrum.

   nucl-exhep-exPRC(2023)·38 citations
3. 03*

   Superfast Quarks in Deuterium

   Dmitriy N. Kim🇺🇸 · Gerald A. Miller🇺🇸

   An extension to our previous study on Nuclear Parton Distribution Functions (nPDFs) using Light-Front Holographic Quantum Chromodynamics (LFHQCD) is presented. We focus on applying the effects of nucleon motion inside the nucleus (Fermi motion/smearing) to deuterium, extending our nPDFs (and hence the DIS $F_2$ structure function for deuterium, $F_2^D$) to the superfast, $x>1$, region. We utilize four different deuteron wavefunctions (AV18, NijmI, NijmII, Nijm93) in this study. We find that our model, with no additional new parameters, is in excellent agreement with deuterium EMC ratio data obtained from the BONuS experiment. Looking beyond conventional nuclear physics, and in anticipation of ongoing 12 GeV experiments at Jefferson Lab, we use a LFHQCD ansatz to predict the contributions of an exotic six-quark state to $F_2^D$ in the superfast region. Our results are that the effects of using other potentials are about the same magnitude as six-quark effects - both have small effects in $x<1$, but have significant contributions at $x>1$.

   ↳ hep-phnucl-exnucl-thPRC(2024)·0 citations
4. 04*

   Conserved number fluctuations under global rotation in a hadron resonance gas model

   Gaurav Mukherjee🇮🇳 · Dipanwita Dutta🇮🇳 · Dipak Kumar Mishra🇮🇳

   Net-baryon number, net-charge and net-strangeness fluctuations measured in ultra-relativistic heavy-ion collisions may reveal details and insights into the quark-hadron transition, hadrochemical freeze-out and possibly aid in the search of the QCD critical point. By scanning in collision energy, current and upcoming heavy-ion facilities aim to explore the finite density regime where the critical point may lie. Effects due to rotation are also expected in case of peripheral collisions and we report on conserved number susceptibilities as calculated in the hadron resonance gas model augmented by a global angular velocity. Since these quantities are directly related to the experimentally measurable moments of the corresponding distributions our results show the possible impact of vorticity on the theoretical baseline and should be useful for referencing with experimental data and QCD-based calculations.

   ↳ hep-phhep-exnucl-exnucl-thEPJC(2024)·13 citations
5. 05*

   Determination of the neutron skin of ${}^{208}$Pb from ultrarelativistic nuclear collisions

   Giuliano Giacalone🇩🇪 · Govert Nijs🇺🇸 · Wilke van der Schee🇨🇭

   Emergent bulk properties of matter governed by the strong nuclear force give rise to physical phenomena across vastly different scales, ranging from the shape of atomic nuclei to the masses and radii of neutron stars. They can be accessed on Earth by measuring the spatial extent of the outer skin made of neutrons that characterises the surface of heavy nuclei. The isotope ${}^{208}$Pb, owing to its simple structure and neutron excess, has been in this context the target of many dedicated efforts. Here, we determine the neutron skin from measurements of particle distributions and their collective flow in ${}^{208}$Pb+${}^{208}$Pb collisions at ultrarelativistic energy performed at the Large Hadron Collider, which are sensitive to the overall size of the colliding ${}^{208}$Pb ions. By means of state-of-the-art global analysis tools within the hydrodynamic model of heavy-ion collisions, we infer a neutron skin $\Delta r_{np}=0.217\pm 0.058$ fm, consistent with nuclear theory predictions, and competitive in accuracy with a recent determination from parity-violating asymmetries in polarised electron scattering. We establish thus a new experimental method to systematically measure neutron distributions in the ground state of atomic nuclei.

   ↳ nucl-thastro-ph.HEhep-exhep-ph+1PRL(2023)·129 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.