Thu·May 23, 2024Thursday·May 23, 2024

1. 01*

   Electromagnetic moments of the odd-mass nickel isotopes ${}^{59-67}$Ni

   P. Müller🇩🇪 · S. Kaufmann🇩🇪 · T. Miyagi🇩🇪 · J. Billowes🇬🇧 · M.L. Bissell🇬🇧 · K. Blaum🇩🇪 · B. Cheal🇬🇧 · R.F. Garcia Ruiz🇨🇭 · W. Gins🇧🇪 · C. Gorges🇩🇪 · H. Heylen🇨🇭 · A. Kanellakopoulos🇧🇪 and 15 other authors

   The magnetic dipole and the spectroscopic quadrupole moments of the nuclear ground states in the odd-mass nickel isotopes ${}^{59-67}$Ni have been determined using collinear laser spectroscopy at the CERN-ISOLDE facility. They are compared to ab initio valence-space in-medium similarity renormalization group (VS-IMSRG) calculations including contributions of two-body currents as well as to shell-model calculations. The two-body-current contributions significantly improve the agreement with experimental data, reducing the mean-square deviation from the experimental moments by a factor of 3 to 5, depending on the employed interaction. For all interactions, the largest contributions are obtained for the $5/2^{-}$ ($7/2^{-}$) isotopes ${}^{65}$Ni (${}^{55}$Ni), which is ascribed to the high angular momentum of the $f$ orbitals. Our results demonstrate that the inclusion of two-body-current contributions to the magnetic moment in an isotopic chain of complex nuclei can be handled by the VS-IMSRG and can outperform phenomenological shell-model calculations using effective $g$-factors in the nickel region.

   nucl-exnucl-thPLB(2024)·10 citations
2. 02*

   In-beam $\gamma -$spectroscopy of the transitional nucleus ${}^{217}$Ac

   Dhananjaya Sahoo · A. Y. Deo · Madhu · Khamosh Yadav🇮🇳 · S. S. Tiwary🇨🇦 · P. C. Srivastava🇮🇳 · R. Palit🇩🇪 · S. K. Tandel · Anil Kumar🇩🇪 · P. Dey🇮🇳 · Biswajit Das · Vishal Malik🇮🇳 and 5 other authors

   High-spin states in the transitional ${}^{217}$Ac nucleus are established up to 3.8 MeV excitation energy and $I^{\pi }=$ 41/2${}^{+}$ with the addition of around 20 new transitions. The structure of the yrast and near-yrast states below the 29/2${}^{+}$ isomer is revisited. The inconsistencies in the level schemes reported earlier are resolved. The level structure above the 29/2${}^{+}$ isomer is established for the first time. Large-basis shell-model calculations with the KHPE interaction are performed to compare the experimentally observed level energies with the theoretical predictions. A comparison with the systematics of the N = 128 isotones suggests that the yrast structures result from a weak coupling of the odd proton to the even-even 216Ra core, which is consistent with the shell-model configurations. Furthermore, alpha decay of the 29/2${}^{+}$ isomer is revisited and the decay scheme established from this work is discussed in the framework of the shell model.

   nucl-exnucl-th0 citations
3. 03*

   Prompt Fission Neutron Spectra of 233U(n,F)

   V.M. Maslov

   Prompt fission neutron spectra produced up to 20 MeV. Simultaneous analysis of measured and calculated data for 233U(n, F), 235U(n, F) and 239Pu(n, F) maintains stronger justification for the predicted PFNS of 233U(n, F). For the latter the reliable measured PFNS data are available at Eth only. Pre-fission neutron spectra influence the partitioning of fission energy between excitation energy and total kinetic energy of fission fragments. For the reactions 233U (n, F) and 235U (n, F) we have shown that the shape of PFNS depends on the fissility of composite and residual nuclei. The correlation of these peculiarities with contributions of (n, xnf) to the (n, F) and competition of (n, ng) and (n, xn) is established. Exclusive neutron spectra (n, xnf) are consistent with cross sections of 235U(n, F), 234U(n, F), 233U(n, F) and 232U(n,F) reactions, as well as neutron emissive spectra of 235U(n,xn) at 14 MeV. Initial model parameters for 233U (n,F) PFNS are fixed by description of prompt fission neutron spectra of 233U (nth, F). We predict the 233U(n,xnf) exclusive pre-fission neutron spectra of 233U(n,xn) reactions, total kinetic energy TKE of fission fragments and products, partials of average PFNS and observed PFNS of 233U(n,F). PFNS of 233U (n, F) are harder than those of 235U(n, F) PFNS, but softer than those of 239Pu(n, F). Difference of average energies of PFNS of 233U (n, F) and 235U(n, F) amounts to 1-3 %. At incident energies higher than (n, 2nf) reaction threshold the observed PFNS may seem similar, though the partial contributions of 233U(n,xnf) and 235U(n,xnf) are quite different. PFNS of 233U(n,xnf) are obtained in the energy range up to 20 MeV.

   ↳ nucl-thnucl-ex2 citations
4. 04*

   Qualitative explanation of the data on the decays $D^0\to a_0(980{)}^{\pm }{\pi }^{\mp }$ and $D^{+}\to a_0(980{)}^{+(0)}{\pi }^{0(+)}$ in the four-quark model of the $a_0(980)$ resonance

   N. N. Achasov🇷🇺 · G. N. Shestakov🇷🇺

   It is shown that the values of the ratios $\mathcal{B}(D^0\to a_0(980{)}^{+}{\pi }^{-})/\mathcal{B}(D^0\to a_0(980{)}^{-}{\pi }^{+})$ and $\mathcal{B}(D^{+}\to a_0(980{)}^{+}{\pi }^0)/\mathcal{B}(D^{+}\to a_0(980{)}^0{\pi }^{+})$, recently measured by the BESIII Collaboration, are naturally explained in the four-quark model of the $a_0(980)$ resonance.

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

   Induced Isotensor Interactions in Heavy-Ion Double-Charge-Exchange Reactions and the Role of Initial and Final State Interactions

   Horst Lenske · Jessica Bellone · Danilo Gambacurta · José-Antonio Lay

   The role of initial state (ISI) and final state (FSI) ion-ion interactions in heavy-ion double-charge-exchange (DCE) reactions $A(Z,N)\to A(Z\pm 2,N\mp 2)$ are studied for double single-charge-exchange (DSCE) reactions given by sequential actions of the isovector nucleon-nucleon (NN) T-matrix. In momentum representation, the second-order DSCE reaction amplitude is shown to be given in factorized form by projectile and target nuclear matrix elements and a reaction kernel containing ISI and FSI. Expanding the intermediate propagator in a Taylor series with respect to auxiliary energy allows us to perform the summation in the leading-order term over intermediate nuclear states in closure approximation. %Please ensure meaning has been retained - corrected HL. The nuclear matrix element attains a form given by the products of two-body interactions directly exciting the $n^2{p}^{-2}$ and $p^2{n}^{-2}$ DCE transitions in the projectile and the target nucleus, respectively. %Please ensure meaning has been retained - corrected HL. A surprising result is that the intermediate propagation induces correlations between the transition vertices, showing that DSCE reactions are a two-nucleon process that resembles a system of interacting spin-isospin dipoles. Transformation of the DSCE NN T-matrix interactions from the reaction theoretical t-channel form to the s-channel operator structure required for spectroscopic purposes is elaborated in detail, showing that, in general, a rich spectrum of spin scalar, spin vector and higher-rank spin tensor multipole transitions will contribute to a DSCE reaction. Similarities (and differences) to two-neutrino double-beta decay (DBD) are discussed. ISI/FSI distortion and absorption effects are illustrated in black sphere approximation and in an illustrative application to data.

   ↳ nucl-thhep-phnucl-exUniverse(2024)·8 citations
6. 06*

   "Soft" interaction parameters setting in the extended quantum molecular dynamics model

   Chen-Zhong Shi · Xiang-Zhou Cai🇨🇳 · Bo-Song Huang · Yu-Gang Ma🇨🇳

   The extended quantum molecular dynamics (EQMD) model is one of the few quantum molecular dynamics (QMD)-like transport approaches that can be used to study the effective clustering structure as well as heavily deformed nuclei in both ground state nuclei and nuclear reactions. However, there are only two parameter sets that lead to hard incompressibility for long times. The aim of the present work is to obtain a soft equation of state (EoS) in the EQMD model. In this context, we take the isoscalar giant monopole resonance (ISGMR), which is sensitive to the EoS, as an example to check our work. By introducing a kind of standard Skyrme energy density functional with different parameter sets, such as SkP, SkT1, and SKXce, whose incompressibility value ranges from 200 to 268 MeV, the ISGMR of ${}^{208}$Pb and other nuclei are studied. When the SkP parameter sets are adopted, our new soft interaction in the EQMD model gives reasonable agreement with the experimental data in the heavy ion regime.

   ↳ nucl-thnucl-exPRC(2024)·4 citations
7. 07*

   Theory of Majorana-Type Heavy Ion Double Charge Exchange Reactions by Pion--Nucleon Isotensor Interactions

   Horst Lenske🇩🇪 · Jessica Bellone🇮🇹 · Maria Colonna🇮🇹 · Danilo Gambacurta🇮🇹

   The theory of heavy ion double charge exchange (DCE) reactions proceeding by effective rank-2 isotensor interactions is presented. Virtual pion--nucleon charge exchange interactions are investigated as the source for induced isotensor interactions, giving rise to the Majorana DCE (MDCE) reaction mechanism. MDCE is of a generic character, proceeding through pairs of complementary (${\pi }^{\pm },{\pi }^{\mp }$) reactions in the projectile and target nucleus. The dynamics of the elementary processes is discussed, where the excitation of pion--nucleon resonances are of central importance. Investigations of initial and final state ion--ion interactions show that these effects are acting as vertex renormalizations. In closure approximation, well justified by the finite pion mass, the second-order transition matrix elements reduce to pion potentials and effective two-body isotensor DCE interactions, giving rise also to two-body correlations in either of the participating nuclei. Connections to neutrinoless Majorana double beta decay (MDBD) are elucidated at various levels of the dynamics, from the underlying fundamental electro-weak and QCD scales to the physical scales of nuclear MDBD and MDCE physics. It is pointed out that heavy ion MDCE reactions may also proceed by competing electro-weak charge exchange processes, leading to lepton MDCE by electrons, positrons, and neutrinos.

   ↳ nucl-thhep-phnucl-exUniverse(2024)·9 citations
8. 08*

   Flavor dependence of unpolarized quark Transverse Momentum Distributions from a global fit

   Alessandro Bacchetta🇮🇹 · Valerio Bertone🇫🇷 · Chiara Bissolotti🇺🇸 · Giuseppe Bozzi🇮🇹 · Matteo Cerutti🇺🇸 · Filippo Delcarro🇮🇹 · Marco Radici🇮🇹 · Lorenzo Rossi🇮🇹 · Andrea Signori (the MAP Collaboration)🇮🇹

   We present an extraction of the unpolarized transverse-momentum-dependent parton distribution and fragmentation functions that takes into account possible differences between quark flavors and final-state hadrons. The extraction is based on experimental measurements from Drell-Yan processes and semi-inclusive deep-inelastic scattering, whose combination is essential to distinguish flavor differences. The analysis is carried out at N${}^3$LL accuracy. The extracted flavor-dependent distributions give a very good description of the data (${\chi }^2/N_{\mathrm{dat}}=1.08$). The resulting uncertainties take fully into account also the uncertainties in the determination of the corresponding collinear distributions.

   ↳ hep-phnucl-exnucl-thJHEP(2024)·103 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.