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Nuclear Theory·nucl-th

Thursday·October 3, 2019

5 papers—4 primary·1 cross-listed

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  1. 01

    [Submitted on 1 Oct 2019]

    New symmetry-adapted ab initio approach to nuclear reactions for intermediate-mass nuclei

    Alexis Mercenne · Kristina D. Launey · Jutta E. Escher · Tomas Dytrych · Jerry P. Draayer

    With a view toward describing reactions of intermediate-mass nuclei from first principles, we present first results for the norm and Hamiltonian overlaps (kernels) for the p-{\alpha}, p-16O and p-20Ne cluster systems using realistic nucleon-nucleon interactions. This is achieved in the framework of a new ab initio approach that combines the symmetry-adapted no-core shell model (SA-NCSM) with the resonating group method (RGM). In this model, a physically relevant basis based on the SU(3) symmetry is used. The structure of the clusters is provided by the ab initio SA-NCSM, which enables the description of spatially enhanced nuclear configurations and heavier nuclei, by exploiting symmetries known to dominate in nuclei. Here, we discuss the applicability and efficacy of this approach.

    Comments:
    7 pages, 4 figures, proceeding CNR*18 Berkeley
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1910.00638 [pdf]
    Springer Proc.Phys.(2020)·2 citations
  2. 02

    [Submitted on 1 Oct 2019]

    Spin dependent ab initio nonlocal No-Core Shell-Model One-Body Densities

    G. Popa · M. Burrows · Ch. Elster · K.D. Launey · P. Maris · S.P. Weppner

    Constructing microscopic effective interactions (`optical potentials') for nucleon-nucleus (NA) elastic scattering requires in first order off-shell nucleon-nucleon (NN) scattering amplitudes between the projectile and the struck target nucleon and nonlocal one-body density matrices. While the NN amplitudes and the {\it ab intio} no-core shell-model (NCSM) calculations always contain the full spin structure of the NN problem, one-body density matrices used in traditional microscopic folding potential neglect spin contributions inherent in the one-body density matrix. Here we derive and show the expectation values of the spin-orbit contribution of the struck nucleon with respect to the rest of the nucleus for He, He, C, and O and compare them with the scalar one-body density matrix.

    Comments:
    Proceedings for IWNT38, Rila, Bulgaria, June 2019, 10 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1910.00683 [pdf]
    Nucl.Theor.(2019)·1 citation
  3. 03

    [Submitted on 1 Oct 2019]

    Hydrodynamic results on multiplicity fluctuations in heavy-ion collisions

    Hong-Hao Ma🇨🇳 · Dan Wen🇨🇳 · Kai Lin🇨🇳 · Wei-Liang Qian🇧🇷 · Bin Wang🇨🇳 · Yogiro Hama🇧🇷 · Takeshi Kodama🇧🇷

    Multiplicity fluctuations are one of the most crucial observables in the Beam Energy Scan program of the Relativistic Heavy Ion Collider. It is understood that they can be utilized to probe the whereabouts of the critical point on the phase diagram of the QCD matter. However, a significant portion of these fluctuations is, apart from that related to the QCD phase transition, attributed to the other origins, which we refer to as "noncritical" ones. The present study is dedicated to the noncritical aspects of the multiplicity fluctuations in heavy-ion collisions. In particular, we focus on those of dynamical origin, such as the hydrodynamic expansion of the system and the event-by-event initial fluctuations, in addition to the usual thermal fluctuations, finite volume corrections, and resonance decay at the freeze-out surface. The obtained results are compared to those of the hadronic resonance gas model as well as to the experimental data.

    Comments:
    20 pages, 3 figures, 1 table
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1910.00705 [pdf]
    PRC(2020)·6 citations
  4. 04

    [Submitted on 30 Sept 2019]

    Mid-Point Technique for Calculating Divergent integrals

    M. Abu-Shady🇪🇬

    A mid-point technique is suggested to overcome the difficulties in other techniques. The modified effective interaction quark potential which uses to calculate different properties of the NJL model such as the constituent quark mass, the pressure, and the energy density is solved using the present technique. The present method gives good accuracy for the mathematical problem and avoids the physical difficulty in the previous works.

    Comments:
    10 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1910.00729 [pdf]
    Annals of Mathematics and Physics, (2019)·0 citations
  5. 05

    [Submitted on 1 Oct 2019] (cross-list from nucl-ex)

    Unique Access to u-Channel Physics: Exclusive Backward-Angle Omega Meson Electroproduction

    W.B. Li🇨🇦 · G.M. Huber🇨🇦 · H.P. Blok🇳🇱 · D. Gaskell🇺🇸 · T. Horn🇺🇸 · K. Semenov-Tian-Shansky🇷🇺 · B. Pire🇫🇷 · L. Szymanowski🇵🇱 · J.-M. Laget🇺🇸 · K. Aniol🇺🇸 · J. Arrington🇺🇸 · E.J. Beise🇺🇸 and 44 other authors

    Backward-angle meson electroproduction above the resonance region, which was previously ignored, is anticipated to offer unique access to the three quark plus sea component of the nucleon wave function. In this letter, we present the first complete separation of the four electromagnetic structure functions above the resonance region in exclusive omega electroproduction off the proton, e + p -> e' + p + omega, at central Q^2 values of 1.60, 2.45 GeV^2 , at W = 2.21 GeV. The results of our pioneering -u ~ -u min study demonstrate the existence of a unanticipated backward-angle cross section peak and the feasibility of full L/T/LT/TT separations in this never explored kinematic territory. At Q^2 =2.45 GeV^2 , the observed dominance of sigma_T over sigma_L, is qualitatively consistent with the collinear QCD description in the near-backward regime, in which the scattering amplitude factorizes into a hard subprocess amplitude and baryon to meson transition distribution amplitudes (TDAs): universal non-perturbative objects only accessible through backward angle kinematics.

    Subjects:
    Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1910.00464 [pdf]
    PRL(2019)·29 citations

Affiliations

first authorsco-authorsvia INSPIRE