Wed·Oct 18, 2023Wednesday·October 18, 2023

1. 01*

   Reactions induced by 30 MeV 3He beam on 9Be: Cluster transfer reactions

   Urazbekov Bakytzhan · Issatayev Talgat · Lukyanov Sergey · Azhibekov Aidos · Denikin Andrey · Mendibayev Kayrat · Janseitov Daniyar · Penionzhkevich Yuri🇷🇺 · Kuterbekov Kayrat · Zholdybayev Timur

   An experiment has been carried out for studying the cluster structure of ${}^9$Be induced by the ${}^3$He ions at the energy of 30 MeV. As results of the nuclear reaction ${}^3$He + ${}^9$Be the differential cross sections for the exit channels - elastic, inelastic, $\alpha$ + ${}^8$Be, ${}^6$He + ${}^6$Be, ${}^6$Li + ${}^6$Li, and ${}^7$Be + ${}^5$He - were measured. Elastic and inelastic scattering data are treated within both the optical model and Coupled channels method. A new set of optical potential was taken for the elastic scattering. The deformation parameter ${\delta }_2$ was established for the transition $3/2\to 5/2$. Cluster transfer reactions are analyzed by means of the coupled reaction channels method. The nuclear reactions with the exit channels ${}^6$He + ${}^6$Be, ${}^6$Li + ${}^6$Li, and ${}^7$Be + ${}^5$He are complemented by two-step transfer mechanisms. The contribution of each reaction mechanisms are shown, and compared with the findings of other authors.

   nucl-exnucl-thCPC(2024)·4 citations
2. 02*

   Electric dipole polarizability of low-lying excited states in atomic nuclei

   José Nicolás Orce🇿🇦 · Cebo Ngwetsheni🇿🇦

   Novel equations for the electric dipole polarizability ${\alpha }_{{}_{E1}}$ of low-lying excited states in atomic nuclei -- and the related $(-2)$ moment of the total photo-absorption cross section, ${\sigma }_{{}_{-2}}$ -- are inferred in terms of electric dipole and quadrupole matrix elements. These equations are valid for arbitrary angular momenta of the initial/ground and final/excited states and have been exploited in fully converged 1$\hslash \omega$ shell-model calculations of selected {\it p-} and {\it sd-}shell nuclei that consider configuration mixing; advancing previous knowledge from ${}^{17}$O to ${}^{36}$Ar, where thousands of electric dipole matrix elements are computed from isovector excitations which include the giant dipole resonance region. Our results are in reasonable agreement with previous shell-model calculations and follow -- except for ${}^{6,7}$Li and ${}^{17,18}$O -- Migdal's global trend provided by the combination of the hydrodynamic model and second-order non-degenerate perturbation theory. Discrepancies in ${}^{6,7}$Li and ${}^{17}$O arise as a result of the presence of $\alpha$-cluster configurations in odd-mass nuclei, whereas the disagreement in ${}^{18}$O comes from the mixing of intruder states, which is lacking in the shell-model interactions. More advanced \emph{ab initio} calculations of the dipole polarizability for low-lying excited states covering all the isovector states within the giant dipole resonance region are missing and could be very valuable to benchmark the results presented here and shed further light on how atomic nuclei polarize away from the ground state

   ↳ nucl-thnucl-exJ.Phys.G(2024)·4 citations
3. 03*

   Viscosities of the Baryon-Rich Quark-Gluon Plasma from Beam Energy Scan Data

   Chun Shen🇺🇸 · Björn Schenke🇺🇸 · Wenbin Zhao🇺🇸

   This work presents the first Bayesian inference study of the (3+1)D dynamics of relativistic heavy-ion collisions and Quark-Gluon Plasma (QGP) viscosities using an event-by-event (3+1)D hydrodynamics + hadronic transport theoretical framework and data from the Relativistic Heavy Ion Collider (RHIC) Beam Energy Scan program. Robust constraints on initial state nuclear stopping and the baryon chemical potential-dependent shear viscosity of the produced quantum chromodynamic (QCD) matter are obtained. The specific bulk viscosity of the QCD matter is found to exhibit a preferred maximum around $\sqrt{s_{\mathrm{NN}}}=19.6$ GeV. This result allows for the alternative interpretation of a reduction (and/or increase) of the speed of sound relative to that of the employed lattice-QCD based equation of state (EOS) for net baryon chemical potential ${\mu }_B\sim 0.2(0.4)$ GeV.

   ↳ nucl-thhep-phnucl-exPRL(2024)·42 citations
4. 04*

   A Data-Driven Density Functional Model for Nuclear Systems

   Zu-Xing Yang🇯🇵 · Xiao-Hua Fan🇨🇳 · Zhi-Pan Li🇨🇳 · Haozhao Liang🇯🇵

   Through ensemble learning with multitasking and complex connection neural networks, we aggregated nuclear properties, including ground state charge radii, binding energies, and single-particle state information obtained from the Kohn-Sham auxiliary single-particle systems. Compared to traditional density functional theory, our model can more accurately characterize nuclear ground state information. Aiming at binding energy, the root mean square error is reduced to 450 keV. Although the complexity involving the nuclear interaction is skipped, the model has not completely devolved into a black box. Leveraging the correlation between densities and binding energies, we calculate the neutron skin thickness of ${}^{208}$Pb to be 0.223 fm. This model will advance our understanding of nuclear properties and accelerate the integration of machine learning into modern nuclear physics.

   ↳ nucl-thnucl-exPRC(2024)·3 citations
5. 05*

   Electroweak Nuclear Properties from Single Molecular Ions in a Penning Trap

   Jonas Karthein🇺🇸 · Silviu-Marian Udrescu🇺🇸 · Scott B. Moroch🇺🇸 · Ivana Belosevic🇨🇦 · Klaus Blaum🇩🇪 · Anastasia Borschevsky🇳🇱 · Yuly Chamorro · David DeMille🇺🇸 · Jens Dilling🇨🇦 · Ronald F. Garcia Ruiz🇺🇸 · Nick R. Hutzler🇺🇸 · Lukáš F. Pašteka🇳🇱 · Ryan Ringle🇺🇸

   We present a novel technique to probe electroweak nuclear properties by measuring parity violation (PV) in single molecular ions in a Penning trap. The trap's strong magnetic field Zeeman shifts opposite-parity rotational and hyperfine molecular states into near degeneracy. The weak interaction-induced mixing between these degenerate states can be larger than in atoms by more than twelve orders of magnitude, thereby vastly amplifying PV effects. The single molecule sensitivity would be suitable for applications to nuclei across the nuclear chart, including rare and unstable nuclei.

   ↳ physics.atom-phnucl-exquant-phPRL(2024)·16 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.