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Nuclear Theory·nucl-th

Monday·March 30, 2020

10 papers—4 primary·6 cross-listed

All10Primary4Cross-lists6
  1. 01

    [Submitted on 27 Mar 2020]

    Calibration of Energy Density Functionals with Deformed Nuclei

    N. Schunck · J. O'Neal · M. Grosskopf · E. Lawrence · S.M. Wild

    Nuclear density functional theory is the prevalent theoretical framework for accurately describing nuclear properties at the scale of the entire chart of nuclides. Given an energy functional and a many-body scheme (e.g., single- or multireference level), the predictive power of the theory depends strongly on how the parameters of the energy functionals have been calibrated with experimental data. Expanded algorithms and computing power have enabled recent optimization protocols to include data in deformed nuclei in order to optimize the coupling constants of the energy functional. The primary motivation of this work is to test the robustness of such protocols with respect to some of the technical and numerical details of the underlying calculations, especially when the calibration explores a large parameter space. To this end, we quantify the effect of these uncertainties on both the optimization and statistical emulation of composite objective functions. We also emphasize that Bayesian calibration can provide better estimates of the theoretical errors used to define objective functions.

    Comments:
    23 pages, 3 figures, 4 tables, 67 references; Submitted to J. Phys. G: Nucl. Part. Phys
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2003.12207 [pdf]
    J.Phys.G(2020)·12 citations
  2. 02

    [Submitted on 27 Mar 2020]

    Three-body vs. dineutron approach to two-neutron radiative capture in He

    L.V. Grigorenko · N.B. Shulgina · M.V. Zhukov

    The low-energy behavior of the strength function for the soft dipole excitation in He is studied theoretically. Use of very large basis sizes and well-grounded extrapolation procedures allows to move to energies as small as 1 keV, at which the low-energy asymptotic behavior of the E1 strength function seems to be achieved. It is found that the low-energy behavior of the strength function is well described in the effective three-body "dynamical dineutron model". The astrophysical rate for the ++He+ is calculated. Comparison with the previous calculations is performed.

    Comments:
    6 pages, 9 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2003.12374 [pdf]
    PLB(2020)·2 citations
  3. 03

    [Submitted on 27 Mar 2020]

    Anomalous chiral transports and spin polarization in heavy-ion collisions

    Yu-Chen Liu🇨🇳 · Xu-Guang Huang🇨🇳

    Relativistic heavy-ion collisions create hot quark-gluon plasma as well as very strong electromagnetic (EM) and fluid vortical fields. The strong EM field and vorticity can induce intriguing macroscopic quantum phenomena such as chiral magnetic, chiral separation, chiral electric separation, and chiral vortical effects as well as the spin polarization of hadrons. These phenomena provide us with experimentally feasible means to study the nontrivial topological sector of quantum chromodynamics, the possible parity violation of strong interaction at high temperature, and the subatomic spintronics of quark-gluon plasma. These studies, both in theory and in experiments, are strongly connected with other subfields of physics such as condensed matter physics, astrophysics, and cold atomic physics, and thus form an emerging interdisciplinary research area. We give an introduction to the aforementioned phenomena induced by the EM field and vorticity and an overview of the current status of their experimental research in heavy-ion collisions. We also briefly discuss spin hydrodynamics as well as chiral and spin kinetic theories.

    Comments:
    35 pages, 13 figures. A review article for Nucl. Sci. Tech. Published version
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2003.12482 [pdf]
    Nucl.Sci.Tech.(2020)·120 citations
  4. 04

    [Submitted on 27 Mar 2020]

    Nonperturbative Effects on Radiative Energy Loss of Heavy Quarks

    Shuai Y.F. Liu🇺🇸 · Ralf Rapp🇺🇸

    The radiative energy loss of fast partons traveling through the quark-gluon plasma (QGP) is commonly studied within perturbative QCD (pQCD). Nonperturbative (NP) effects, which are expected to become important near the critical temperature, have been much less investigated. Here, we utilize a recently developed -matrix approach to incorporate NP effects for gluon emission off heavy quarks propagating through the QGP. We set up four cases that contain, starting from a Born diagram calculation with color-Coulomb interaction, an increasing level of NP components, by subsequently including (remnants of) confining interactions, resummation in the heavy-light scattering amplitude, and off-shell spectral functions for both heavy and light partons. For each case we compute the power spectra of the emitted gluons, heavy-quark transport coefficients (drag and transverse-momentum broadening, ), and the path-length dependent energy loss within a "QGP brick" at fixed temperature. Investigating the differences in these quantities between the four cases illustrates how NP mechanisms affect gluon radiation processes. While the baseline perturbative processes experience a strong suppression of soft radiation due to thermal masses of the emitted gluons, confining interactions, ladder resummations and broad spectral functions (re-)generate a large enhancement toward low momenta and low temperatures. For example, for a 10 GeV charm quark at 200 MeV temperature, they enhance the transport coefficients by up to a factor of 10, while the results smoothly converge to perturbative results at sufficiently hard scales.

    Comments:
    24 pages, 13 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2003.12536 [pdf]
    JHEP(2020)·23 citations

Affiliations

first authorsco-authorsvia INSPIRE