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Nuclear Theory·nucl-th

Tuesday·November 2, 2021

15 papers—7 primary·8 cross-listed

All15Primary7Cross-lists8
  1. 01

    Solving the three-dimensional Skyrme Hartree-Fock-Bogoliubov problem using the mixed-basis method

    Yue Shi · Nobuo Hinohara

    Background: The symmetry-unrestricted Hartree-Fock-Bogoliubov (HFB) simulation is important for describing various quantum many-body systems. However, the HFB problem in Cartesian coordinate space is numerically challenging. Purpose: For describing ground states without imposing axial symmetry and looking ahead to future extension for dynamics with full time dependence, we present a numerically efficient implementation of the three-dimensional (3D) HFB code. Methods: We develop a 3D Skyrme HFB code based on the mixed-basis representation (HFBmix) which consists of two harmonic-oscillator (HO) bases in the x- and y-directions, and finite-difference (FD) basis in the z-direction in solving the nuclear 3D HFB problem. Results: The results show very well agreement among all the three codes (HFBmix, HO3D, and hfodd). Especially for the HF calculations, the differences in total energies are on the order of a few keV for the lightest O and Mg nuclei. The HFBmix is applied to spherical, prolate, and triaxial systems, and gives the same quadrupole moments for the deformed nuclei as those of the HO-based calculations. Feasibility of the HFBmix is demonstrated in the fission isomer and barrier calculations of 240Pu. Conclusions: The HFBmix is useful for solving the nuclear 3D HFB problem for its numerical efficiency. Future work will include the analysis of deformed drip-line systems and systematic potential-energy surface calculation for fission-path analysis as well as the time-dependent extension of the HFBmix code for dynamics calculations.

    nucl-th2 citations
  2. 02

    Statistical uncertainty estimation of higher-order cumulants with finite efficiency and its application in heavy-ion collisions

    Fan Si · Yifei Zhang

    We derive the general analytical expressions for the statistical uncertainties of cumulants up to fourth order including an efficiency correction. The analytical expressions have been tested with a toy Monte Carlo model analysis. An application to the study of particle multiplicity fluctuations in heavy-ion collisions is investigated. In this derivation, a mathematical proof is given that the validity of an averaged efficiency correction and the fluctuations induced by the non-uniformity of efficiency can be eliminated. The estimation of statistical uncertainties using the analytical formulas is found to be significantly faster than the commonly used bootstrap method. The simplicity and efficiency of using the analytical formulas may be useful for massive data analysis in many fields.

    nucl-thPRC(2022)·0 citations
  3. 03

    Local two- and three-nucleon chiral interactions

    Maria Piarulli🇺🇸 · Rocco Schiavilla🇺🇸

    Understanding the structure and reactions of nuclei from first principles has been a long-standing goal of nuclear physics. In this respect, few- and many-body systems provide a unique laboratory for studying nuclear interactions. In the past couple of decades, the modeling of nuclear interactions has progressed significantly owing, in particular, to the development of chiral effective field theory (EFT), a low-energy effective representation of quantum chromodynamics (QCD). Within EFT, many studies have dealt with the construction of both two- and three-nucleon interactions. The aim of the present article is to provide a concise account of chiral interaction models that are local in configuration space, and to report on a selection of recent results for nuclear systems obtained with these interactions.

    nucl-thFew Body Syst.(2021)·3 citations
  4. 04

    Multi-reference many-body perturbation theory for nuclei II -- Ab initio study of neon isotopes via PGCM and IM-NCSM calculations

    Mikael Frosini🇫🇷 · Thomas Duguet🇫🇷 · Jean-Paul Ebran🇫🇷 · Benjamin Bally🇪🇸 · Tobias Mongelli🇩🇪 · Tomás R. Rodríguez🇪🇸 · Robert Roth🇩🇪 · Vittorio Somà🇫🇷

    The neon isotopic chain displays a rich phenomenology, ranging from clustering in the ground-state of the self-conjugate doubly open-shell stable Ne isotope to the physics of the island of inversion around the neutron-rich Ne isotope. This second (i.e. Paper II) of the present series proposes an extensive ab initio study of neon isotopes based on two complementary many-body methods, i.e. the quasi-exact in-medium no-core shell model (IM-NCSM) and the projected generator coordinate method (PGCM) that is ideally suited to capturing strong static correlations associated with shape deformation and fluctuations. Calculations employ a state-of-the-art generation of chiral effective field theory Hamiltonians and evaluate the associated systematic uncertainties. In spite of missing so-called dynamical correlations, which can be added via the multi-reference perturbation theory proposed in the first paper (i.e. Paper I) of the present series, the PGCM is shown to be a suitable method to tackle the low-lying spectroscopy of complex nuclei. Still, describing the physics of the island of inversion constitutes a challenge that seems to require the inclusion of dynamical correlations. This is addressed in the third paper (i.e. Paper III) of the present series.

    nucl-thEPJA(2022)·97 citations
  5. 05

    Forward coherent and mesons production in the photon induced reaction on nuclei

    Swapan Das🇮🇳

    The differential cross sections of the forward coherent and mesons photoproduction from nuclei have been calculated using the Glauber model for the nuclear reaction. The measured cross section of the elementary reaction, i.e., reaction, are used as input in the Glauber model. The experimentally determined free-space scattering parameters of the quoted mesons have been used to evaluate the meson nucleus interactions. The sensitivity of the cross section to the Fermi-motion of the nucleon and the nucleon-nucleon short-range correlation in the nucleus are studied. The calculated results are compared with the measured cross sections.

    nucl-thnucl-exPhys.Scripta(2021)·2 citations
  6. 06

    Proton-neutron pairing and binding energies of nuclei close to N=Z line

    D. Negrea · N. Sandulescu · D. Gambacurta

    We analyse the contribution of isovector and isoscalar proton-neutron pairing to the binding energies of even-even nuclei with and atomic mass . The binding energies are calculated in the mean-field approach by coupling a Skyrme-type functional to an isovector-isoscalar pairing force of zero range. The latter is treated in the framework of quartet condensation model (QCM), which conserves exactly the particle number and the isospin. The interdependence of pairing and deformation is taken into account by performing self-consistent Skyrme-HF+QCM calculations in the intrinsic system. It is shown that the binding energies are not changing much when the isoscalar pairing is switched on. This fact is related to the off-diagonal matrix elements of the pairing force, which is less attractive for the isoscalar force, and to the competition between the isoscalar and isovector pairing channels.

    nucl-thPRC(2022)·5 citations
  7. 07

    What Can Possibly Go Wrong?

    Harald W. Griesshammer (George Washington U.)🇺🇸

    A lot. [In this hard, unbiased and objective look at some past and continuing blunders in following Weinberg's suggestions to arrive at a comprehensive description of Nuclear Physics using Effective Field Theories, some names and citations are withheld to protect the innocent.]

    nucl-thhep-phphysics.hist-phFew Body Syst.(2022)·14 citations

Affiliations

first authorsco-authorsvia INSPIRE