Nuclear Theory·nucl-th

Friday·August 23, 2019

9 papers—4 primary·5 cross-listed

01
Skyrme Functional with Tensor Terms from ab initio Calculations: Results for the Spin-Orbit Splittings
Shihang Shen · Gianluca Colò · Xavier Roca-Maza
A new Skyrme functional including tensor terms is presented. The tensor terms have been determined by fitting the results of relativistic Brueckner-Hartree-Fock (RBHF) studies on neutron-proton drops. Unlike all previous studies, where the tensor terms were usually determined by fitting to experimental data of single-particle levels, the pseudodata calculated by RBHF does not contain beyond mean-field effect such as the particle-vibration coupling and, therefore, can provide information on the tensor term without ambiguities. The obtained new functional, named SAMi-T, can describe well ground-state properties such as binding energies, radii, spin-orbit splittings and, at the same time, the excited state properties such as those of the Giant Monopole Resonance (GMR), Giant Dipole Resonance (GDR), Gamow-Teller Resonance (GTR), and Spin-Dipole Resonance (SDR).
nucl-thActa Phys.Polon.Supp.(2019)·0 citations
02
New magicity $N = 32$ and $34$ triggered by strong couplings between Dirac inversion partners
Jia Liu · Yi Fei Niu · Wen Hui Long
Inspired by recent experiments, the successive new magicity $N = 32$ and $34$ in Ca isotopes are studied within the relativistic density functional theory. It is illustrated that the strong couplings between the $s_{1/2}$ and neutron ( $ν$ ) $ν 2 p_{1/2}$ orbits, here referred as "Dirac inversion partners" (DIPs), play a key role in opening both subshells $N = 32$ and $34$ . Such strong couplings originate from the inversion similarity between the DIPs, that the upper component of the Dirac spinor of one partner shares the same orbital angular momentum as the lower component of the other, and vice versa. Following the revealed mechanism, it is predicted that the magicity $N = 32$ is reserved until $^{48}$ S, but vanishes in $^{46}$ Si.
nucl-thPLB(2020)·33 citations
03
From response functions to cross sections in neutrino scattering off the deuteron and trinucleons
J. Golak · R. Skibinski · K. Topolnicki · H. Witala · A. Grassi · H. Kamada · L. E. Marcucci
Response functions, differential cross sections and total cross sections for several (anti)neutrino induced reactions on 2H, 3He and 3H are calculated in momentum space for (anti)neutrino energies up to 160 MeV, using the AV18 nucleon-nucleon potential and a single-nucleon weak current operator. This work is a continuation of our investigations presented in J. Golak et al. [Phys. Rev. C 98, 015501 (2018)].
nucl-thPRC(2019)·7 citations
04
First-forbidden transitions in the reactor anomaly
Leendert Hayen🇧🇪 · Joel Kostensalo🇫🇮 · Nathal Severijns🇧🇪 · Jouni Suhonen🇫🇮
We describe here microscopic calculations performed on the dominant forbidden transitions in reactor antineutrino spectra above 4 MeV using the nuclear shell model. By taking into account Coulomb corrections in the most complete way, we calculate the shape factor with the highest fidelity and show strong deviations from allowed approximations and previously published results. Despite small differences in the ab initio electron cumulative spectra, large differences on the order of several percents are found in the antineutrino spectra. Based on the behaviour of the numerically calculated shape factors we propose a parametrization of forbidden spectra. Using Monte Carlo techniques we derive an estimated spectral correction and uncertainty due to forbidden transitions. We establish the dominance and importance of forbidden transitions in both the reactor anomaly and spectral shoulder analysis. Based on these results, we conclude that a correct treatment of forbidden transitions is indispensable in both the normalization anomaly and spectral shoulder.
nucl-thhep-exnucl-exPRC(2019)·102 citations
05
Optimal Control for the Quantum Simulation of Nuclear Dynamics
Eric T. Holland🇺🇸 · Kyle A. Wendt🇺🇸 · Konstantinos Kravvaris🇺🇸 · Xian Wu🇺🇸 · W. Erich Ormand🇺🇸 · Jonathan L DuBois🇺🇸 · Sofia Quaglioni🇺🇸 · Francesco Pederiva🇮🇹
We propose a method for enacting the unitary time propagation of two interacting neutrons at leading order of chiral effective field theory by efficiently encoding the nuclear dynamics into a single multi-level quantum device. The emulated output of the quantum simulation shows that, by applying a single gate that draws on the underlying characteristics of the device, it is possible to observe multiple cycles of the nucleons' dynamics before the onset of decoherence. Owing to the signal's longevity, we can then extract spectroscopic properties of the simulated nuclear system. This allows us to validate the encoding of the nuclear Hamiltonian and the robustness of the simulation in the presence of quantum-hardware noise by comparing the extracted spectroscopic information to exact calculations. This work paves the way for transformative calculations of dynamical properties of nuclei on near-term quantum devices.
↳ quant-phnucl-thPRA(2020)·52 citations
06
Intrinsic three-body nuclear interaction from a constituent quark model
Aaron Park🇰🇷 · Su Houng Lee🇰🇷
We study the short distance part of the intrinsic three-nucleon interaction in a constituent quark model with color-spin interaction. For that purpose we first calculate the transformation coefficient between the tribaryon configuration and their corresponding three baryon basis. Using a formula for the intrinsic three-body interaction in terms of a tribaryon configuration, we find that after subtracting the corresponding two-baryon contributions, the intrinsic three-body interaction vanishes in flavor SU(3) symmetric limit for all quantum numbers for the three nucleon states. We further find that the intrinsic three-body interaction also vanishes for flavor-spin type of quark interaction.
↳ hep-phnucl-thPRC(2019)·6 citations
07
Renormalization group improved pressure for cold and dense QCD
Jean-Loïc Kneur🇫🇷 · Marcus Benghi Pinto🇧🇷 · Tulio Eduardo Restrepo🇧🇷
We apply the renormalization group optimized perturbation theory (RGOPT)to evaluate the QCD (matter) pressure at the two-loop level considering three flavors of massless quarks in a dense and cold medium. Already at leading order ( $α_{s}^{0}$ ), which builds on the simple one loop (RG resummed) term, our technique provides a non-trivial non-perturbative approximation which is completely renormalization group invariant. At the next-to-leading order the comparison between the RGOPT and the pQCD predictions shows that the former method provides results which are in better agreement with the state-of-the-art $hi g h er or d er$ perturbative results, which include a contribution of order $α_{s}^{3} ln^{2} α_{s}$ . At the same time one also observes that the RGOPT predictions are less sensitive to variations of the arbitrary $MS ˉ$ renormalization scale than those obtained with pQCD. These results indicate that the RGOPT provides an efficient resummation scheme which may be considered as an alternative to lattice simulations at high baryonic densities.
↳ hep-phhep-thnucl-thPRD(2019)·20 citations
08
Thermal Broadening of Bottomonia: Lattice Non-Relativistic QCD with Extended Operators
Rasmus Larsen🇺🇸 · Stefan Meinel🇺🇸 · Swagato Mukherjee🇺🇸 · Peter Petreczky🇺🇸
We present lattice non-relativistic QCD calculations of bottomonium correlation functions at temperatures $T ≃ 150 - 350$ MeV. The correlation functions were computed using extended bottomonium operators, and on background gauge-field configurations for 2+1-flavor QCD having physical kaon and nearly-physical pion masses. We analyzed these correlation functions based on simple theoretically-motivated parameterizations of the corresponding spectral functions. The results of our analyses are compatible with significant in-medium thermal broadening of the ground state S- and P-wave bottomonia.
↳ hep-lathep-phnucl-thPRD(2019)·69 citations
09
Nucleon-antinucleon annihilation at LEAR
Claude Amsler🇦🇹
This report is a historical review of the salient results in low energy antiproton-proton and antineutron-proton annihilation obtained at the Low Energy Antiproton Ring (LEAR), which was operated at CERN between 1983 and 1996. The intention is to provide guidelines for future experiments at the CERN AD/ELENA complex and elsewhere. In the spirit of this workshop, hadron spectroscopy - one of the cornerstones at LEAR - is briefly mentioned, while emphasis is put on the annihilation mechanism on one and two nucleons, the final state multiplicity distributions and the contributions from quarks, in particular in annihilation channels involving strangeness.
↳ hep-phnucl-exnucl-th17 citations

Affiliations

first authorsco-authorsvia INSPIRE