PaperPanorama

Nuclear Theory·nucl-th

Wednesday·March 20, 2019

13 papers7 primary·6 cross-listed

  1. 01

    [Submitted on 18 Mar 2019]

    The JETSCAPE framework

    J. H. Putschke🇺🇸 · K. Kauder🇺🇸 · E. Khalaj🇺🇸 · A. Angerami🇺🇸 · S. A. Bass🇺🇸 · S. Cao🇺🇸 · J. Coleman🇺🇸 · L. Cunqueiro🇺🇸 · T. Dai🇺🇸 · L. Du🇺🇸 · H. Elfner🇩🇪 · D. Everett🇺🇸 and 33 other authors

    The JETSCAPE simulation framework is an overarching computational envelope for developing complete event generators for heavy-ion collisions. It allows for modular incorporation of a wide variety of existing and future software that simulates different aspects of a heavy-ion collision. The default JETSCAPE package contains both the framework, and an entire set of indigenous and third party routines that can be used to directly compare with experimental data. In this article, we outline the algorithmic design of the JETSCAPE framework, define the interfaces and describe the default modules required to carry out full simulations of heavy-ion collisions within this package. We begin with a description of the various physics elements required to simulate an entire event in a heavy-ion collision, and distribute these within a flowchart representing the event generator and statistical routines for comparison with data. This is followed by a description of the abstract class structure, with associated members and functions required for this flowchart to work. We then define the interface that will be required for external users of JETSCAPE to incorporate their code within this framework and to modify existing elements within the default distribution. We conclude with a discussion of some of the physics output for both - and - collisions from the default distribution, and an outlook towards future releases. In the appendix, we discuss various architectures on which this code can be run and outline our benchmarks on similar hardware.

    Comments:
    93 pages, 13 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1903.07706 [pdf]
    191 citations
  2. 02

    [Submitted on 18 Mar 2019]

    Forbidden transitions in neutral and charged current interactions between low-energy neutrinos and Argon

    Nils Van Dessel🇧🇪 · Natalie Jachowicz🇧🇪 · Alexis Nikolakopoulos🇧🇪

    Background: The study of low-energy neutrinos and their interactions with atomic nuclei is crucial to several open problems in physics, including the neutrino mass hierarchy, CP-violation, candidates of Beyond Standard Model physics and supernova dynamics. Examples of experiments include CAPTAIN at SNS as well as DUNE's planned detection program of supernova neutrinos. Purpose: We present cross section calculations for quasielastic charged current and neutral current neutrinos at low energies, with a focus on Ar. We also take a close look at pion decay-at-rest neutrino spectra, which are used in e.g. the SNS experiment at Oakridge. Method and results: We employ a Hartree Fock + Continuum Random Phase Approximations (HF+CRPA) framework, which allows us to model the responses and include the effects of long-range correlations. It is expected to provide a good framework to calculate forbidden transitions, whose contribution which we show to be non-negligible. Conclusions: Forbidden transitions can be expected to contribute sizeably to the reaction strength at typical low-energy kinematics, such as DAR neutrinos. Modeling and Monte Carlo simulations need to take all due care to account for the influence of their contributions.

    Comments:
    11 pages, 16 figures; minor corrections to v2
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1903.07726 [pdf]
    PRC(2019)·19 citations
  3. 03

    [Submitted on 19 Mar 2019]

    A Pattern for the Flavor Dependence of the Quark-Gluon Interaction

    Muyang Chen🇨🇳 · Lei Chang🇨🇳

    A flavor dependent kernel is constructed based on the rainbow-ladder truncation of the Dyson-Schwinger and Bethe-Salpeter equation approach of Quantum Chromodynamics. The quark-antiquark interaction is composed of a flavor dependent infrared part and a flavor independent ultraviolet part. Our model gives a successful and unified description of the light, heavy and heavy-light ground pseudoscalar and vector mesons. For the first time, our model shows that the infrared enhanced quark-antiquark interaction is stronger and wider for the lighter quark.

    Comments:
    6 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1903.07808 [pdf]
    CPC(2019)·29 citations
  4. 04

    [Submitted on 19 Mar 2019]

    Role of dynamic pairing correlations in fission dynamics

    R. Bernard🇫🇷 · S.A. Giuliani🇺🇸 · L.M. Robledo🇪🇸

    We study the role of dynamic pairing correlations in fission dynamics by considering intrinsic Hartree-Fock-Bogoliubov wave functions that are obtained by minimizing the particle number projected energy. For the restricted variational space, the set of self-consistent wave functions with different values of proton and neutron number particle fluctuations are considered. The particle number projected energy is used to define potential energy surface for fission whereas collective inertias are computed within the traditional formulas for the intrinsic states. The results show that the effect of the restricted variation after particle number projection in the potential energy surface is small while collective inertias substantially decrease. On the other hand, we show that this quenching is strongly mitigated when Coulomb antipairing is considered. In the light of these beyond mean-field calculations, the validity of traditional fission calculations is discussed.

    Comments:
    7 pages, 3 Figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1903.07892 [pdf]
    PRC(2019)·23 citations
  5. 05

    [Submitted on 19 Mar 2019]

    Poincare' covariant light-front spectral function and transverse momentum distribution

    Emanuele Pace · Giovanni Salme' · Sergio Scopetta

    In valence approximation the fermion correlator is simply related to the light-front spectral function. Then the leading twist time-reversal even transverse momentum distributions can be explicitly obtained from the light-front wave function of the system and the twist-three distributions are linear combinations of the transverse distributions at leading twist.

    Comments:
    4 pages, talk given at the XXII International Conference on Few-Body Problems in Physics (FB22), Caen, France, July 9 - 13, 2018
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1903.08073 [pdf]
    0 citations
  6. 06

    [Submitted on 19 Mar 2019]

    Muon capture in nuclei: an ab initio approach based on quantum Monte Carlo methods

    A. Lovato🇺🇸 · N. Rocco🇺🇸 · R. Schiavilla🇺🇸

    An ab initio quantum Monte Carlo method is introduced for calculating total rates of muon weak capture in light nuclei with mass number . As a first application of the method, we perform a calculation of the rate in He in a dynamical framework based on realistic two- and three-nucleon interactions and realistic nuclear charge-changing weak currents. The currents include one- and two-body terms induced by - and -meson exchange, and -to- excitation, and are constrained to reproduce the empirical value of the Gamow-Teller matrix element in tritium. We investigate the sensitivity of theoretical predictions to current parametrizations of the nucleon axial and induced pseudoscalar form factors as well as to two-body contributions in the weak currents. The large uncertainties in the measured values obtained from bubble-chamber experiments (carried out over 50 years ago) prevent us from drawing any definite conclusions.

    Comments:
    6 pages, 1 figure
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1903.08078 [pdf]
    PRC(2019)·19 citations
  7. 07

    [Submitted on 19 Mar 2019]

    Particle-Set Identification method to study multiplicity fluctuations

    M. Gazdzicki🇵🇱 · M. I. Gorenstein🇺🇦 · M. Mackowiak-Pawlowska🇵🇱 · A. Rustamov🇩🇪

    In this paper a new method of experimental data analysis, the Particle-Set Identification method, is presented. The method allows to reconstruct moments of multiplicity distribution of identified particles. The difficulty the method copes with is due to incomplete particle identification -- a particle mass is frequently determined with a resolution which does not allow for a unique determination of the particle type. Within this method the moments of order are calculated from mean multiplicities of -particle sets of a given type. The Particle-Set Identification method remains valid even in the case of correlations between mass measurements for different particles. This distinguishes it from the Identity method introduced by us previously to solve the problem of incomplete particle identification in studies of particle fluctuations.

    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1903.08103 [pdf]
    NPA(2020)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE