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Nuclear Theory·nucl-th

Thursday·January 29, 2015

8 papers—5 primary·3 cross-listed

All8Primary5Cross-lists3
  1. 01

    [Submitted on 27 Jan 2015]

    Nuclear equation of state and finite nucleon volumes

    Jacek Rożynek🇵🇱

    It is shown how the Equation of State (EoS) depends on nucleon properties inside Nuclear Matter (NM). We propose to benefit from the concept of enthalpy in order to include volume corrections to the nucleon rest energy, which are proportional to pressure and absent in a standard Relativistic Mean Field (RMF) with point-like nucleons. As a result, the nucleon mass can decrease inside NM, making the model nonlinear and the EoS softer. The course of the EoS in our RMF model agrees with a semi-empirical estimate and is close to the results obtained from extensive DBHF calculations with a Bonn A potential, which produce an EoS stiff enough to describe neutron star properties (mass--radius constraint), especially the masses of PSR J1614_2230 and PSR J0348_0432, known as the most massive () neutron stars. The presented model has proper saturation properties, including a good value of compressibility.

    Comments:
    12 pages,3 figures. Accepted in Journal of Physics G; Nuclear and Particle Physics. arXiv admin note: substantial text overlap with arXiv:1311.3591
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1501.06945 [pdf]
    J.Phys.G(2015)·4 citations
  2. 02

    [Submitted on 28 Jan 2015]

    Present Status of Fission Research Based on TDDFT

    Yoritaka Iwata

    Fission resulting from collision of atomic nuclei is systematically investigated based on time-dependent density functional calculations. Time-dependent density functional theory (TDDFT) is a framework, which enables us to treat quantum many-body dynamics with nucleon degrees of freedom. In this article a theoretical framework called Composite-Nucleus Constrained TDDFT is introduced, and charge equilibrium hypothesis for collision fission dynamics is examined.

    Comments:
    To appear in the proceedings of the 2014 symposium on nuclear data
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1501.06970 [pdf]
    JAEA-Conf 2015-003, INDC(JPN)-201, 93 (20…·0 citations
  3. 03

    [Submitted on 28 Jan 2015]

    Complex-energy approach to sum rules within nuclear density functional theory

    Nobuo Hinohara · Markus Kortelainen · Witold Nazarewicz · Erik Olsen

    The linear response of the nucleus to an external field contains unique information about the effective interaction, correlations, and properties of its excited states. To characterize the response, it is useful to use its energy-weighted moments, or sum rules. By comparing computed sum rules with experimental values, the information content of the response can be utilized in the optimization process of the nuclear Hamiltonian or EDF. But the additional information comes at a price: compared to the ground state, computation of excited states is more demanding. To establish an efficient framework to compute sum rules of the response that is adaptable to the optimization of the nuclear EDF and large-scale surveys of collective strength, we have developed a new technique within the complex-energy FAM based on the QRPA. To compute sum rules, we carry out contour integration of the response function in the complex-energy plane. We benchmark our results against the conventional matrix formulation of the QRPA theory, the Thouless theorem for the energy-weighted sum rule, and the dielectric theorem for the inverse energy-weighted sum rule. We demonstrate that calculated sum-rule values agree with those obtained from the matrix formulation of the QRPA. We also discuss the applicability of both the Thouless theorem about the energy-weighted sum rule and the dielectric theorem for the inverse energy-weighted sum rule to nuclear density functional theory in cases when the EDF is not based on a Hamiltonian. The proposed sum-rule technique based on the complex-energy FAM is a tool of choice when optimizing effective interactions or energy functionals. The method is very efficient and well-adaptable to parallel computing. The FAM formulation is especially useful when standard theorems based on commutation relations involving the nuclear Hamiltonian and external field cannot be used.

    Comments:
    11 pages, 2 figures, submitted to Phys. Rev. C
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1501.06994 [pdf]
    PRC(2015)·27 citations
  4. 04

    [Submitted on 28 Jan 2015]

    2p-2h excitations in neutrino scattering: angular distribution and frozen approximation

    I. Ruiz Simo🇪🇸 · C. Albertus🇪🇸 · J.E. Amaro🇪🇸 · M.B. Barbaro🇮🇹 · J.A. Caballero🇪🇸 · T.W. Donnelly🇺🇸

    We study the phase-space dependence of 2p-2h excitations in neutrino scattering using the relativistic Fermi gas model. We follow a similar approach to other authors, but focusing in the phase-space properties, comparing with the non-relativistic model. A careful mathematical analysis of the angular distribution function for the outgoing nucleons is performed. Our goals are to optimize the CPU time of the 7D integral to compute the hadron tensor in neutrino scattering, and to conciliate the different relativistic and non relativistic models by describing general properties independently of the two-body current. For some emission angles the angular distribution becomes infinite in the Lab system, and we derive a method to integrate analytically around the divergence. Our results show that the frozen approximation, obtained by neglecting the momenta of the two initial nucleons inside the integral of the hadron tensor, reproduces fairly the exact response functions for constant current matrix elements.

    Comments:
    8 pages, 4 figures. Contribution to 16th International Workshop on Neutrino Factories and Future Neutrino Beam Facilities, 25-30 August, 2014. Held at University of Glasgow, United Kingdom
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1501.07120 [pdf]
    PoS(2015)·1 citation
  5. 05

    [Submitted on 28 Jan 2015]

    On the accuracy of using Fokker Planck equation in heavy ion collision

    Nirupam Dutta🇮🇳 · Trambak Bhattacharyya🇮🇳

    Application of Fokker-Planck equation to heavy quark transport in the evolving medium created in heavy ion collision is critically scrutinised. We realise that the approach introduces a moderate uncertainty in drag and diffusion coefficients culminating in huge ambiguity in the theoretical prediction of nuclear modification factor . Quantitative estimation of the error is presented by considering recent developments in this field.

    Comments:
    3 pages
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1501.07230 [pdf]
    0 citations

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first authorsco-authorsvia INSPIRE