Tue·Nov 28, 2023Tuesday·November 28, 2023

1. 01*

   Overview of the experimental quest for the giant pairing vibration

   M. Assié🇫🇷

   The search for the giant pairing vibration (GPV) has a long standing history since the 1970's when it was predicted. First experimental measurements focused on (p,t) transfer reactions in the heavy nuclei and did not show convincing evidence. The discovery of a signal compatible with the GPV in the light carbon isotopes has renewed the interest for the GPV. It triggered new theoretical models showing that the GPV in the heavy nuclei might be too wide or too melted to be observed and triggered new experiments with radioactive probes based on (${}^6$He,${}^4$He) transfer.

   nucl-exnucl-thNuovo Cim.C(2024)·0 citations
2. 02*

   Proton-unbound states in ${}^{24}\mathrm{Al}$ relevant for the ${}^{23}\mathrm{Mg}(p,\gamma )$ reaction in novae

   E. C. Vyfers · V. Pesudo🇪🇸 · S. Triambak🇿🇦 · M. Kamil🇿🇦 · P. Adsley🇿🇦 · B. A. Brown🇺🇸 · H. Jivan🇿🇦 · D. J. Marin-Lambarri🇿🇦 · R. Neveling🇿🇦 · J. C. Nzobadila Ondze🇿🇦 · P. Papka🇿🇦 · L. Pellegri🇿🇦 and 4 other authors

   Background: The nucleosynthesis of several proton-rich nuclei is determined by radiative proton-capture reactions on unstable nuclei in nova explosions. One such reaction is ${}^{23}\mathrm{Mg}(p,\gamma {)}^{24}\mathrm{Al}$, which links the NeNa and MgAl cycles in oxygen-neon (ONe) novae. Purpose: To extract ${}^{23}\mathrm{Mg}(p,\gamma )$ resonance strengths from a study of proton-unbound states in ${}^{24}\mathrm{Al}$, produced via the ${}^{24}$Mg(${}^3$He,$t$) reaction. Methods: A beam of ${}^3{\mathrm{He}}^{2+}$ ions at 50.7 MeV was used to produce the states of interest in ${}^{24}$Al. Proton-triton angular correlations were measured with a $K=600$ QDD magnetic spectrometer and a silicon detector array, located at iThemba LABS, South Africa. Results: We measured the excitation energies of the four lowest proton-unbound states in ${}^{24}$Al and place lower-limits on ${\Gamma }_p/\Gamma$ values for these four states. Together with shell-model calculations of partial gamma widths, the experimental data are also used to determine resonance strengths for the three lowest ${}^{23}\mathrm{Mg}(p,\gamma {)}^{24}\mathrm{Al}$ resonances. Conclusions: The energy of the dominant first ${}^{23}\mathrm{Mg}(p,\gamma )$ resonance is determined to be $E_r=478\pm 4$ keV, with a resonance strength $\omega \gamma =19\pm 9$ meV.

   nucl-exPRC(2024)·0 citations
3. 03*

   Pion and kaon electromagnetic and gravitational form factors

   Yin-Zhen Xu🇪🇸 · Minghui Ding🇩🇪 · Khépani Raya🇪🇸 · Craig D. Roberts🇨🇳 · José Rodríguez-Quintero🇪🇸 · Sebastian M. Schmidt🇩🇪

   A unified set of predictions for pion and kaon elastic electromagnetic and gravitational form factors is obtained using a symmetry-preserving truncation of each relevant quantum field equation. A key part of the study is a description of salient aspects of the dressed graviton + quark vertices. The calculations reveal that each meson's mass radius is smaller than its charge radius, matching available empirical inferences; and meson core pressures are commensurate with those in neutron stars. The analysis described herein paves the way for a direct calculation of nucleon gravitational form factors.

   ↳ hep-phhep-exhep-latnucl-ex+1EPJC(2024)·60 citations
4. 04*

   Improved determination of the oscillator parameters in nuclei

   Latsamy Xayavong🇰🇷 · Yeunhwan Lim🇰🇷

   The oscillator parameter in nuclei is refitted to reproduce the available charge radius data. As an important improvement, we include the Coulomb term evaluated within the assumption of a uniformly charged sphere, and take into account the symmetry effect induced by the difference between N and Z numbers in a straightforward manner using the conventional parameterization. The Coulomb interaction has repulsive effect, causing the wave functions to extend further toward the nucleus exterior, resulting in an effectively larger oscillator length parameter. The symmetry effect is attractive for protons in neutron-rich nuclei and for neutrons in proton-rich nuclei, and repulsive for the other cases. Therefore, three distinct oscillator parameters are determined: one for protons, one for neutrons, and one isospin-invariant version, which is obtained by subtracting the Coulomb and symmetry contributions. Additionally, we explore the direct fit of the harmonic oscillator wave functions to the eigenfunctions of the Hartree-Fock mean field using the Skyrme interaction. Generally, this method agrees well with the others for light nuclei, typically up to ${}^{40}$Ca. Beyond this nucleus, however, the results begin to diverge over the orbits chosen for the fit. Only the parameters values obtained for the last occupied states agree remarkably well with the conventional ones throughout the mass range under consideration.

   ↳ nucl-thnucl-ex0 citations
5. 05*

   ANCs of the bound states of ${}^{16}$O deduced from elastic $\alpha$-${}^{12}$C scattering data

   Shung-Ichi Ando (Sunmoon Univ.)🇰🇷

   Asymptotic normalization coefficients (ANCs) of the $0_1^{+}$, $0_2^{+}$, $1_1^{-}$, $2_1^{+}$, $3_1^{-}$ ($l_{ith}^{\pi }$) bound states of ${}^{16}$O are deduced from the phase shift data of elastic $\alpha$-${}^{12}$C scattering at low energies. $S$ matrices of elastic $\alpha$-${}^{12}$C scattering are constructed within cluster effective field theory (EFT), in which both bound and resonant states of ${}^{16}$O are considered. Parameters in the $S$ matrices are fitted to the precise phase shift data below the $p$-${}^{15}$N breakup energy for the partial waves of $l=0,1,2,3,4,5,6$, and the ANCs are calculated by using the wave function normalization factors of ${}^{16}$O propagators for $l=0,1,2,3$. We review the values of ANCs, which are compared with other results in the literature, and discuss uncertainties of the ANCs obtained from the elastic $\alpha$-${}^{12}$C scattering data in cluster EFT.

   ↳ nucl-thnucl-exFew Body Syst.(2024)·4 citations
6. 06*

   Collinear Laser Spectroscopy of $2{}^3{S}_1\to 2{}^3{P}_J$ transitions in helium-like ${}^{12}{\mathrm{C}}^{4+}$

   Phillip Imgram🇩🇪 · Kristian König🇩🇪 · Bernhard Maaß🇩🇪 · Patrick Müller🇩🇪 · Wilfried Nörtershäuser🇩🇪

   Transition frequencies and fine-structure splittings of the $2{}^3{S}_1\to 2{}^3{P}_J$ transitions in helium-like ${}^{12}{\mathrm{C}}^{4+}$ were measured by collinear laser spectroscopy on a 1-ppb level. Accuracy is increased by more than three orders of magnitude with respect to previous measurements, enabling tests of recent non-relativistic QED calculations including terms up to $m{\alpha }^7$. Deviations between the theoretical and experimental values are within theoretical uncertainties and are ascribed to $m{\alpha }^8$ and higher-order contributions in the series expansion of the NR-QED calculations. Finally, prospects for an all-optical charge radius determination of light isotopes are evaluated.

   ↳ physics.atom-phnucl-exPRL(2023)·14 citations
7. 07*

   Collinear laser spectroscopy of highly charged ions produced with an electron beam ion source

   Phillip Imgram🇩🇪 · Kristian König🇩🇪 · Bernhard Maaß🇩🇪 · Patrick Müller🇩🇪 · Wilfried Nörtershäuser🇩🇪

   Collinear laser spectroscopy has been performed on He-like C${}^{4+}$ ions extracted from an electron beam ion source (EBIS). In order to determine the transition frequency with the highest-possible accuracy, the lineshape of the fluorescence response function was studied for pulsed and continuous ion extraction modes of the EBIS in order to optimize its symmetry and linewidth. We found that the best signal-to-noise ratio is obtained using the continuous beam mode for ion extraction. Applying frequency-comb-referenced collinear and anticollinear laser spectroscopy, we achieved a measurement accuracy of better than 2\,MHz including statistical and systematic uncertainties. The origin and size of systematic uncertainties, as well as further applications for other isotopes and elements are discussed.

   ↳ physics.atom-phnucl-exPRA(2023)·10 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.