PaperPanorama
FAQ

Nuclear Theory·nucl-th

Tuesday·February 6, 2018

6 papers—3 primary·3 cross-listed

All6Primary3Cross-lists3
  1. 01

    [Submitted on 4 Feb 2018]

    Characterizing the astrophysical S-factor for C+C with wave-packet dynamics

    Alexis Diaz-Torres · Michael Wiescher

    A quantitative study of the astrophysically important sub-barrier fusion of C+C is presented. Low-energy collisions are described in the body-fixed reference frame using wave-packet dynamics within a nuclear molecular picture. A collective Hamiltonian drives the time propagation of the wave-packet through the collective potential-energy landscape. The fusion imaginary potential for specific dinuclear configurations is crucial for understanding the appearance of resonances in the fusion cross section. The theoretical sub-barrier fusion cross sections explain some observed resonant structures in the astrophysical S-factor. These cross sections monotonically decline towards stellar energies. The structures in the data that are not explained are possibly due to cluster effects in the nuclear molecule, which are to be included in the present approach.

    Comments:
    Submitted to Physical Review C; 7 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1802.01160 [pdf]
    PRC(2018)·57 citations
  2. 02

    [Submitted on 4 Feb 2018]

    Effects of unconventional breakup modes on incomplete fusion of weakly bound nuclei

    Alexis Diaz-Torres · Daanish Quraishi

    The incomplete fusion dynamics of Li + Bi collisions at energies above the Coulomb barrier is investigated. The classical dynamical model implemented in the {\sc platypus} code is used to understand and quantify the impact of both Li resonance states and transfer-triggered breakup modes (involving short-lived projectile-like nuclei such as Be and Li) on the formation of incomplete fusion products. Model calculations explain the experimental incomplete-fusion excitation function fairly well, indicating that (i) delayed direct breakup of Li reduces the incomplete fusion cross-sections, and (ii) the neutron-stripping channel practically determines those cross-sections.

    Comments:
    Accepted in Physical Review C
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1802.01181 [pdf]
    PRC(2018)·27 citations
  3. 03

    [Submitted on 5 Feb 2018]

    U(n, f) Independent Fission Product Yield and Isomeric Ratio Calculated with the Statistical Hauser-Feshbach Theory

    Shin Okumura · Toshihiko Kawano · Patrick Talou · Patrick Jaffke · Satoshi Chiba

    We have developed a Hauser-Feshbach fission fragment decay model, HFD, which can be applied to the statistical decay of more than 500 primary fission fragment pairs (1,000 nuclides) produced by the neutron induced fission of U. The fission fragment yield and the total kinetic energy TKE are model inputs, and we estimate them from available experimental data for the U(n,f) system. The model parameters in the statistical decay calculation are adjusted to reproduce some fission observables, such as the neutron emission multiplicity , its distribution , and the mass dependence . The calculated fission product yield and isomeric ratio are compared with experimental data. We show that the calculated independent fission product yield at the thermal energy reproduces the experimental data well, while the calculated isomeric ratios tend to be lower than the Madland-England model prediction. The model is extended to higher incident neutron energies up to the second chance fission threshold. We demonstrate for the first time that most of the isomeric ratios stay constant, although the production of isomeric state itself changes as the incident energy increases.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1802.01248 [pdf]
    J.Nucl.Sci.Tech.(2018)·56 citations
  4. 04

    [Submitted on 2 Dec 2017] (cross-list from hep-ph)

    The semileptonic baryonic decay

    Hai-Yang Cheng🇹🇼 · Xian-Wei Kang🇹🇼

    The decay with a proton-antiproton pair in the final state is unique in the sense that it is the only semileptonic baryonic decay which is physically allowed in the charmed meson sector. Its measurement will test our basic knowledge on semileptonic decays and the low-energy interactions. Taking into account the major intermediate state contributions from and , we find that its branching fraction is at the level of . The location and the nature of state are crucial for the precise determination of the branching fraction. We wish to trigger a new round of a careful study with the upcoming more data in BESIII as well as the future super tau-charm factory.

    Comments:
    final version, accepted for publication in Phys. Lett. B
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    1712.00566 [pdf]
    PLB(2018)·14 citations
  5. 05

    [Submitted on 3 Feb 2018] (cross-list from cond-mat.quant-gas)

    Precursor of Superfluidity in a Strongly Interacting Fermi Gas with Negative Effective Range

    Hiroyuki Tajima

    We theoretically investigate the effects of pairing fluctuations in an ultracold Fermi gas near a Feshbach resonance with a negative effective range. By employing a many-body T-matrix theory with a coupled boson-fermion model, we show that the single-particle density of states exhibits the so-called pseudogap phenomenon which is a precursor of superfluidity induced by strong pairing fluctuations. We clarify the region where strong pairing fluctuations play a crucial role in single-particle properties, from the broad-resonance region to the narrow-resonance limit at the divergent two-body scattering length. We also extrapolate the effects of pairing fluctuations to the positive-effective-range region from our results near the narrow Feshbach resonance. Results shown in this paper are relevant to the connection between ultracold Fermi gases and low-density neutron matter from the viewpoint of finite-effective-range corrections.

    Comments:
    21 pages, 8 figures
    Subjects:
    Quantum Gases (cond-mat.quant-gas); Nuclear Theory (nucl-th)
    arXiv:
    1802.00919 [pdf]
    PRA(2018)·9 citations
  6. 06

    [Submitted on 5 Feb 2018] (cross-list from hep-ph)

    Soft photon and two hard jets forward production in proton-nucleus collisions

    Tolga Altinoluk🇵🇱 · Néstor Armesto🇪🇸 · Alex Kovner🇺🇸 · Michael Lublinsky🇮🇱 · Elena Petreska🇳🇱

    We calculate the cross section for production of a soft photon and two hard jets in the forward rapidity region in proton-nucleus collisions at high energies. The calculation is performed within the hybrid formalism. The hardness of the final particles is defined with respect to the saturation scale of the nucleus. We consider both the correlation limit of small momentum imbalance and the dilute target limit where the momentum imbalance is of the order of the hardness of the jets. The results depend on the first two transverse-momentum-dependent (TMD) gluon distributions of the nucleus.

    Comments:
    39 pages, 4 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1802.01398 [pdf]
    JHEP(2018)·27 citations

Affiliations

first authorsco-authorsvia INSPIRE