PaperPanorama
FAQ

Nuclear Theory·nucl-th

Monday·May 9, 2016

5 papers—2 primary·3 cross-listed

All5Primary2Cross-lists3
  1. 01

    [Submitted on 6 May 2016]

    Quantal rotation and its coupling to intrinsic motion in nuclei

    Takashi Nakatsukasa (1 and 2) · Kenichi Matsuyanagi (2 and 3) · Masayuki Matsuzaki (4) · Yoshifumi R. Shimizu (5) ((1) University of Tsukuba, (2) RIKEN Nishina Center, (3) YITP, (4) Fukuoka University of Education, (5) Kyushu University)

    Symmetry breaking is an importance concept in nuclear physics and other fields of physics. Self-consistent coupling between the mean-field potential and the single-particle motion is a key ingredient in the unified model of Bohr and Mottelson, which could lead to a deformed nucleus as a consequence of spontaneous breaking of the rotational symmetry. Some remarks on the finite-size quantum effects are given. In finite nuclei, the deformation inevitably introduces the rotation as a symmetry-restoring collective motion (Anderson-Nambu-Goldstone mode), and the rotation affects the intrinsic motion. In order to investigate the interplay between the rotational and intrinsic motions in a variety of collective phenomena, we use the cranking prescription together with the quasiparticle random phase approximation. At low spin, the coupling effect can be seen in the generalized intensity relation. A feasible quantization of the cranking model is presented, which provides a microscopic approach to the higher-order intensity relation. At high spin, the semiclassical cranking prescription works well. We discuss properties of collective vibrational motions under rapid rotation and/or large deformation. The superdeformed shell structure plays a key role in emergence of a new soft mode which could lead to instability toward the octupole shape. A wobbling mode of excitation, which is a clear signature of the triviality, is discussed in terms of a microscopic point of view. A crucial role played by the quasiparticle alignment is presented.

    Comments:
    38 pages, 11 figures, Contribution to the Focus issue to celebrate the 40 year anniversary of the 1975 Nobel Prize
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1605.01876 [pdf]
    Phys.Scripta(2016)·19 citations
  2. 02

    [Submitted on 6 May 2016]

    Role of the total isospin 3/2 component in three-nucleon reactions

    H. Witała · J. Golak · R. Skibiński · K. Topolnicki · E. Epelbaum · K. Hebeler · H. Kamada · H. Krebs · U.-G. Meißner · A. Nogga

    We discuss the role of the three-nucleon isospin T=3/2 amplitude in elastic neutron-deuteron scattering and in the deuteron breakup reaction. The contribution of this amplitude originates from charge-independence breaking of the nucleon-nucleon potential and is driven by the difference between neutron-neutron (proton-proton) and neutron-proton forces. We study the magnitude of that contribution to the elastic scattering and breakup observables, taking the locally regularized chiral N4LO nucleon-nucleon potential supplemented by the chiral N2LO three-nucleon force. For comparison we employ also the Av18 nucleon-nucleon potential combined with the Urbana IX three-nucleon force. We find that the isospin T=3/2 component is important for the breakup reaction and the proper treatment of charge-independence breaking in this case requires the inclusion of the 1S0 state with isospin T=3/2. For neutron-deuteron elastic scattering the T=3/2 contributions are insignificant and charge-independence breaking can be accounted for by using the effective t-matrix generated with the so-called "2/3-1/3" rule.

    Comments:
    24 pages, 8 figures, 3 Tables
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1605.02011 [pdf]
    Few Body Syst.(2016)·14 citations
  3. 03

    [Submitted on 3 May 2016] (cross-list from physics.pop-ph)

    Gravitational Wave for a pedestrian

    A K Chaudhuri🇮🇳

    The physics of gravitational wave and its detection in the recent experiment by the LIGO collaboration is discussed in simple terms for a general audience. The main article is devoid of any mathematics, but an appendix is included for inquisitive readers where essential mathematics for general theory of relativity and gravitational waves are given.

    Comments:
    Few mistakes are corrected. 19 pages, 8 figures
    Subjects:
    physics.pop-ph (physics.pop-ph); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1605.00761 [pdf]
    3 citations
  4. 04

    [Submitted on 6 May 2016] (cross-list from hep-ph)

    Magnetic shift of the chemical freezeout and electric charge fluctuations

    Kenji Fukushima🇯🇵 · Yoshimasa Hidaka🇯🇵

    We discuss the effect of a strong magnetic field on the chemical freezeout points in the ultrarelativistic heavy-ion collision. As a result of the inverse magnetic catalysis or the magnetic inhibition, the crossover onset to hot and dense matter out of quarks and gluons should be shifted to a lower temperature. To quantify this shift we employ the hadron resonance gas model and an empirical condition for the chemical freezeout. We point out that the charged particle abundances are significantly affected by the magnetic field so that the electric charge fluctuation is largely enhanced especially at high baryon density. The charge conservation partially cancels the enhancement but our calculation shows that the electric charge fluctuation and the charge chemical potential could serve as a magnetometer. We find that the fluctuation exhibits a crossover behavior rapidly increased for eB >~ (0.4GeV)^2, while the charge chemical potential has better sensitivity to the magnetic field.

    Comments:
    5 pages, 4 figures; Fig.4 is updated for the electric charge susceptibility and the charge chemical potential as functions of B
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1605.01912 [pdf]
    PRL(2016)·46 citations
  5. 05

    [Submitted on 6 May 2016] (cross-list from hep-ph)

    Reactor Neutrino Spectra

    A. C. Hayes🇺🇸 · Petr Vogel🇺🇸

    We present a review of the antineutrino spectra emitted from reactors. Knowledge of these and their associated uncertainties are crucial for neutrino oscillation studies. The spectra used to-date have been determined by either conversion of measured electron spectra to antineutrino spectra or by summing over all of the thousands of transitions that makeup the spectra using modern databases as input. The uncertainties in the subdominant corrections to beta-decay plague both methods, and we provide estimates of these uncertainties. Improving on current knowledge of the antineutrino spectra from reactors will require new experiments. Such experiments would also address the so-called reactor neutrino anomaly and the possible origin of the shoulder observed in the antineutrino spectra measured in recent high-statistics reactor neutrino experiments.

    Comments:
    Submitted for publication in the Annual Review of Nuclear and Particle Science, Vol.66
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1605.02047 [pdf]
    Ann.Rev.Nucl.Part.Sci.(2016)·176 citations

Affiliations

first authorsco-authorsvia INSPIRE