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Nuclear Theory·nucl-th

Tuesday·April 7, 2015

8 papers—4 primary·4 cross-listed

All8Primary4Cross-lists4
  1. 01

    Electric Dipole Polarizability in Pb as a Probe of the Symmetry Energy and Neutron Matter around

    Zhen Zhang · Lie-Wen Chen

    It is currently a big challenge to accurately determine the symmetry energy and the pure neutron matter equation of state , even their values around saturation density . We find that the electric dipole polarizability in Pb can be determined uniquely by the magnitude of the or almost equivalently the at subsaturation densities around , shedding a light upon the genuine correlation between the and the . By analyzing the experimental data of the in Pb from RCNP using a number of non-relativistic and relativistic mean-field models, we obtain very stringent constraints on and around . The obtained constraints are found to be in good agreement with the results extracted in other analyses. In particular, our results provide for the first time the experimental constraints on around , which are in harmony with the recent determination of from microscopic theoretical studies and potentially useful in constraining the largely uncertain many-nucleon interactions in microscopic calculations of neutron matter.

    nucl-thastro-ph.SRnucl-exPRC(2015)·107 citations
  2. 02

    Effects of thermal shape fluctuations and pairing fluctuations on the giant dipole resonance in warm nuclei

    A. K. Rhine Kumar · P. Arumugam · N. Dinh Dang

    Apart from the higher limits of isospin and temperature, the properties of atomic nuclei are intriguing and less explored at the limits of lowest but finite temperatures. At very low temperatures there is a strong interplay between the shell (quantal fluctuations), statistical (thermal fluctuations), and residual pairing effects as evidenced from the studies on giant dipole resonance (GDR). In our recent work [Phys. Rev. C \textbf{90}, 044308 (2014)], we have outlined some of our results from a theoretical approach for such warm nuclei where all these effects are incorporated along within the thermal shape fluctuation model (TSFM) extended to include the fluctuations in the pairing field. In this article, we present the complete formalism based on the microscopic-macroscopic approach for determining the deformation energies and a macroscopic approach which links the deformation to GDR observables. We discuss our results for the nuclei Tc, Sn, Au, and Pb, and corroborate with the experimental data available. The TSFM could explain the data successfully at low temperature only with a proper treatment of pairing and its fluctuations. More measurements with better precision could yield rich information about several phase transitions that can happen in warm nuclei.

    nucl-thPRC(2015)·25 citations
  3. 03

    On the Nuclear Mechanisms Underlying the Heat Production by the E-Cat

    Norman D. Cook · Andrea Rossi

    We discuss the isotopic abundances found in the E-Cat reactor with regard to the nuclear mechanisms responsible for excess heat. We argue that a major source of energy is a reaction between the first excited-state of Li-7 and a proton, followed by the breakdown of Be-8 into two alphas with high kinetic energy, but without gamma radiation. The unusual property of the Li-7 isotope that allows this reaction is similar to the property that underlies the Mossbauer effect: the presence of unusually low-lying excited states in stable, odd-Z and/or odd-N nuclei. We use the lattice version of the independent-particle model (IPM) of nuclear theory to show how the geometrical structure of isotopes indicate nuclear reactions that are not predicted in the conventional version of the IPM. Finally, we speculate on similar mechanisms that may be involved in other low-energy nuclear reactions (LENR).

    physics.gen-ph0 citations
  4. 04

    Van der Waals Equation of State with Fermi Statistics for Nuclear Matter

    V. Vovchenko · D. V. Anchishkin · M. I. Gorenstein

    The van der Waals (VDW) equation of state is a simple and popular model to describe the pressure function in equilibrium systems of particles with both repulsive and attractive interactions. This equation predicts an existence of a first-order liquid-gas phase transition and contains a critical point. Two steps to extend the VDW equation and make it appropriate for new physical applications are carried out in this paper: 1) the grand canonical ensemble formulation; 2) an inclusion of the quantum statistics. The VDW equation with Fermi statistics is then applied to a description of the system of interacting nucleons. The VDW parameters and are fixed to reproduce the properties of nuclear matter at saturation density fm and zero temperature. The model predicts a location of the critical point for the symmetric nuclear matter at temperature MeV and nucleon number density fm.

    nucl-thPRC(2015)·108 citations

Affiliations

first authorsco-authorsvia INSPIRE