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Nuclear Theory·nucl-th

Thursday·December 12, 2019

16 papers—6 primary·10 cross-listed

All16Primary6Cross-lists10
  1. 01

    Microscopic predictions for production of neutron rich nuclei in the reaction

    K. Godbey🇺🇸 · C. Simenel🇦🇺 · A.S. Umar🇺🇸

    Background: Production of neutron-rich nuclei is of vital importance to both understanding nuclear structure far from stability and to informing astrophysical models of the rapid neutron capture process (r-process). Multinucleon transfer (MNT) in heavy-ion collisions offers a possibility to produce neutron-rich nuclei far from stability. Purpose: The reaction has been suggested as a potential candidate to explore the neutron-rich region surrounding the principal fragments. The current study has been conducted with the goal of providing guidance for future experiments wishing to study this (or similar) system. Methods: Time-dependent Hartree-Fock (TDHF) and its time-dependent random-phase approximation (TDRPA) extension are used to examine both scattering and MNT characteristics in . TDRPA calculations are performed to compute fluctuations and correlations of the neutron and proton numbers, allowing for estimates of primary fragment production probabilities. Results: Both scattering results from TDHF and transfer results from the TDRPA are presented for different energies, orientations, and impact parameters. In addition to fragment composition, scattering angles and total kinetic energies, as well as correlations between these observables are presented. Conclusions: appears to be an interesting probe for the mid-mass neutron-rich region of the chart of nuclides. The predictions of both TDHF and TDRPA are speculative, and will benefit from future experimental results to test the validity of this approach to studying MNT in heavy, symmetric collisions.

    nucl-thPRC(2020)·41 citations
  2. 02

    Ab initio nuclear thermodynamics

    Bing-Nan Lu🇺🇸 · Ning Li🇺🇸 · Serdar Elhatisari🇹🇷 · Dean Lee🇺🇸 · Joaquín E. Drut🇺🇸 · Timo A. Lähde🇩🇪 · Evgeny Epelbaum🇩🇪 · Ulf-G. Meißner🇩🇪

    We propose a new Monte Carlo method called the pinhole trace algorithm for {\it ab initio} calculations of the thermodynamics of nuclear systems. For typical simulations of interest, the computational speedup relative to conventional grand-canonical ensemble calculations can be as large as a factor of one thousand. Using a leading-order effective interaction that reproduces the properties of many atomic nuclei and neutron matter to a few percent accuracy, we determine the location of the critical point and the liquid-vapor coexistence line for symmetric nuclear matter with equal numbers of protons and neutrons. We also present the first {\it ab initio} study of the density and temperature dependence of nuclear clustering.

    nucl-thcond-mat.stat-mechhep-latnucl-exPRL(2020)·61 citations
  3. 03

    Delineating the properties of neutron star matter in cold, dense QCD

    Toru Kojo🇨🇳

    The properties of dense QCD matter are delineated through the construction of equations of state which should be consistent with the low and high density limits of QCD, nuclear laboratory experiments, and the neutron star observations. These constraints, together with the causality condition of the sound velocity, are used to develop the picture of hadron-quark continuity in which hadronic matter continuously transforms into quark matter (modulo small 1st order phase transitions). The resultant unified equation of state at zero temperature and -equilibrium, which we call Quark-Hadron-Crossover (QHC19), is consistent with the measured properties of neutron stars as well as the microphysics known for the hadron phenomenology. In particular to (: saturation density) the gluons remain as non-perturbative as in vacuum and the strangeness can be as abundant as up- and down-quarks at the core of two-solar mass neutron stars. Within our modeling the maximum mass is found less than times solar mass and the baryon density at the core ranges in -8.

    nucl-thastro-ph.HEhep-latPoS(2019)·0 citations
  4. 04

    Calculated solar-neutrino capture rate for a radiochemical 205 Tl-based solar-neutrino detector

    Joel Kostensalo🇫🇮 · Jouni Suhonen🇫🇮 · Kai Zuber🇩🇪

    Radiochemical experiments for low-energy solar-neutrino detection have been making headlines by exploiting the isotopes \iso{Cl}{37} and \iso{Ga}{71}. Such a very low-threshold measurement of this type can also be performed using \iso{Tl}{205}, which has been considered for decades for this purpose. A unique feature of this detector nucleus is the integration is the solar-neutrino flux over millions of years owing to its long-living daughter \iso{Pb}{205}. In this study we have calculated for the first time the cross section for the charged-current solar-neutrino scattering off \iso{Tl}{205}. Taking into account the solar-model-predicted neutrino fluxes and the electron-neutrino survival probabilities, a solar-neutrino capture rate of 62.2 SNU is determined, a value significantly smaller than in previous estimates.

    nucl-thhep-phPRC(2020)·7 citations
  5. 05

    Low-energy neutron scattering on light nuclei and B as a B-- three-body system in the unitary limit

    Jaume Carbonell🇫🇷 · Emiko Hiyama🇯🇵 · Rimantas Lazauskas🇫🇷 · F. Miguel Marqués🇫🇷

    We consider the evolution of the neutron-nucleus scattering length for the lightest nuclei. We show that, when increasing the number of neutrons in the target nucleus, the strong Pauli repulsion is weakened and the balance with the attractive nucleon-nucleon interaction results into a resonant virtual state in B. We describe B in terms of a B-- three-body system where the two-body subsystems B- and - are unbound (virtual) states close to the unitary limit. The energy of B ground state is well reproduced and two low-lying resonances are predicted. Their eventual link with the Efimov physics is discussed. This model can be extended to describe the recently discovered resonant states in B.

    nucl-thnucl-exquant-phSciPost Phys.Proc.(2020)·2 citations
  6. 06

    Fission of relativistic nuclei with fragment excitation and reorientation

    C.A. Bertulani🇺🇸 · Y. Kucuk🇹🇷 · R. Lozeva🇫🇷

    Experimental studies of fission induced in relativistic nuclear collisions show a systematic enhancement of the excitation energy of the primary fragments by a factor of ~ 2, before their decay by fission and other secondary fragments. Although it is widely accepted that by doubling the energies of the single-particle states may yield a better agreement with fission data, it does not prove fully successful, since it is not able to explain yields for light and intermediate mass fragments. State-of-the-art calculations are successful to describe the overall shape of the mass distribution of fragments, but fail within a factor of 2-10 for a large number of individual yields. Here, we present a novel approach that provides an account of the additional excitation of primary fragments due to final state interaction with the target. Our method is applied to the 238U + 208Pb reaction at 1 GeV/nucleon (and is applicable to other energies), an archetype case of fission studies with relativistic heavy ions, where we find that the large probability of energy absorption through final state excitation of giant resonances in the fragments can substantially modify the isotopic distribution of final fragments in a better agreement with data. Finally, we demonstrate that large angular momentum transfers to the projectile and to the primary fragments via the same mechanism imply the need of more elaborate theoretical methods than the presently existing ones.

    nucl-thnucl-exPRL(2020)·9 citations

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first authorsco-authorsvia INSPIRE