PaperPanorama
FAQ

Nuclear Theory·nucl-th

Thursday·October 10, 2019

8 papers—5 primary·3 cross-listed

All8Primary5Cross-lists3
  1. 01

    [Submitted on 8 Oct 2019]

    Baseline predictions of elliptic flow and fluctuations at the RHIC Beam Energy Scan using response coefficients

    S. Rao🇺🇸 · M. Sievert🇺🇸 · J. Noronha-Hostler🇺🇸

    Currently the RHIC Beam Energy Scan is exploring a new region of the Quantum Chromodynamic phase diagram at large baryon densities that approaches nuclear astrophysics regimes. This provides an opportunity to study relativistic hydrodynamics in a regime where the net conserved charges of baryon number, strangeness, and electric charge play a role, which will significantly change the theoretical approach to simulating the baryon-dense Quark-Gluon Plasma. Here we detail many of the important changes needed to adapt both initial conditions and the medium to baryon-rich matter. Then, we make baseline predictions for the elliptical flow and fluctuations based on extrapolating the physics at LHC and top RHIC energies to support future analyses of where and how the new baryon-dense physics causes these extrapolations to break down. First we compare eccentricities across beam energies, exploring their underlying assumptions; we find the the extrapolated initial state is predicted to be nearly identical to that at AuAu GeV. Then the final flow harmonic predictions are based on linear+cubic response. We discuss preliminary STAR results in order to determine the implications that they have for linear+cubic response coefficients at the lowest beam energy of AuAu GeV.

    Comments:
    35 pages, 19 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1910.03677 [pdf]
    PRC(2021)·43 citations
  2. 02

    [Submitted on 9 Oct 2019]

    Density functional theory for nuclear fission -- a proposal

    J. Dobaczewski

    The fission process is a fascinating phenomenon in which the atomic nucleus, a compact self-bound mesoscopic system, undergoes a spontaneous or induced quantum transition into two or more fragments. A predictive, accurate and precise description of nuclear fission, rooted in a fundamental quantum many-body theory, is one of the biggest challenges in science. Current approaches assume adiabatic motion of the system with internal degrees of freedom at thermal equilibrium. With parameters adjusted to data, such modelling works well in describing fission lifetimes, fragment mass distributions, or their total kinetic energies. However, are the assumptions valid? For the fission occurring at higher energies and/or shorter times, the process is bound to be non-adiabatic and/or non-thermal. The vision of this project is to go beyond these approximations, and to obtain a unified description of nuclear fission at varying excitation energies. The key elements of this project are the use of nuclear density functional theory with novel, nonlocal density functionals and innovative high-performance computing techniques. Altogether, the project aims at better understanding of nuclear fission, where slow, collective, and semi-classical effects are intertwined with fast, microscopic, quantum evolution.

    Comments:
    18 LaTeX pages
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1910.03924 [pdf]
    6 citations
  3. 03

    [Submitted on 8 Oct 2019]

    Triangular symmetry in cluster nuclei

    R. Bijker · A.H. Santana-Valdés

    In this contribution, we present evidence for the occurrence of triangular symmetry in cluster nuclei. We discuss the structure of rotational bands for 3-alpha and 3-alpha+1 configurations with triangular D(3h) symmetry by exploiting the double group D'(3h), and study the application to 12C and 13C. The structure of rotational bands can be used as a fingerprint of the underlying geometric configuration of alpha-particles.

    Comments:
    6 pages, 6 figures, 1 table, invited talk at INPC, Glasgow, July 29 - August 2, 2019. To be published in J. Phys. Conf. Ser. arXiv admin note: substantial text overlap with arXiv:1903.02068
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1910.04064 [pdf]
    J.Phys.Conf.Ser.(2020)·1 citation
  4. 04

    [Submitted on 9 Oct 2019]

    Taming nuclear complexity with a committee of multilayer neural networks

    R.-D. Lasseri🇫🇷 · D. Regnier🇫🇷 · J.-P. Ebran🇫🇷 · A. Penon

    We demonstrate that a committee of deep neural networks is capable of predicting the ground-state and excited energies of more than 1800 atomic nuclei with an accuracy akin to the one achieved by state-of-the-art nuclear energy density functionals (EDFs) and a major speed-up. An active learning strategy is proposed to train this algorithm with a minimal set of 210 nuclei. This approach enables future fast studies of the influence of EDFs parametrizations on structure properties over the whole nuclear chart and suggests that for the first time an artificial intelligence successfully encoded the laws of nuclear deformation.

    Subjects:
    Nuclear Theory (nucl-th); Computational Physics (physics.comp-ph)
    arXiv:
    1910.04132 [pdf]
    PRL(2020)·83 citations
  5. 05

    [Submitted on 9 Oct 2019]

    Short-range correlations for neutrinoless double-beta decay and low-momentum NN potentials

    L. Coraggio🇮🇹 · N. Itaco🇮🇹 · R. Mancino🇮🇹

    We approach the calculation of the nuclear matrix element of the neutrinoless double-beta decay process, considering the light-neutrino-exchange channel, by way of the realistic shell-model. In particular the focus of our work is spotted on the role of the short-range correlations, which should be taken into account because of the short-range repulsion of the realistic potentials. Our shell-model wave functions are calculated using an effective Hamiltonian derived from the high-precision CD-Bonn nucleon-nucleon potential, the latter renormalized by way of the so-called V-low-k approach. The renormalization procedure decouples the repulsive high-momentum component of the potential from the low-momentum ones by the introduction of a cutoff Lambda, and is employed to renormalize consistently the two-body neutrino potentials to calculate the nuclear matrix elements of candidates to this decay process in mass interval ranging from A=76 up to A=136. We study the dependence of the decay operator on the choice of the cutoff, and compare our results with other approaches that can be found in present literature.

    Comments:
    6 pages, 1 figure, 1 table, submitted to the Conference Proceedings of the 27th International Nuclear Physics Conference, 29 July -2 August 2019, Glasgow (UK)
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1910.04146 [pdf]
    J.Phys.Conf.Ser.(2020)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE