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Nuclear Theory·nucl-th

Thursday·March 19, 2015

5 papers—2 primary·3 cross-listed

All5Primary2Cross-lists3
  1. 01

    [Submitted on 18 Mar 2015]

    Nucleon-nucleon resonances at intermediate energies using a complex energy formalism

    G. Papadimitriou🇺🇸 · J.P. Vary🇺🇸

    We apply our method of complex scaling, valid for a general class of potentials, in a search for nucleon-nucleon S-matrix poles up to 2 GeV laboratory kinetic energy. We find that the realistic potentials JISP16, constructed from inverse scattering, and chiral field theory potentials NLO and NLO support resonances in energy regions well above their fit regions. In some cases these resonances have widths that are narrow when compared with the real part of the S-matrix pole.

    Comments:
    7 pages, 5 figures, 2 Tables
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1503.05277 [pdf]
    PLB(2015)·9 citations
  2. 02

    [Submitted on 18 Mar 2015]

    Signature of nonexponential nuclear decay

    A Ray · A K Sikdar · A De

    Precision tests of decay law of radioactive nuclei have not so far found any deviation from the exponential decay law at early time, as predicted by quantum mechanics. In this paper, we show that the quantum decoherence time (i.e. the timescale of nonexponential decay) of the quasifission or fission process should be of the order of attosecond considering the atom of the fissioning nucleus as a quantum detector. Hence, the observed decay timescale of the quasifission or fission process of even highly excited (EX greater than 50 MeV) transuranium and uraniumlike complexes should be rather long (of the order of attosecond) in spite of their very fast exponential decay timescale (of the order of zeptosecond) as measured by the nuclear techniques. Recent controversy regarding the observation of very long (of the order of attosecond ) and very short (of the order of zeptosecond ) quasifission or fission timescales for similar systems at similar excitation energies as obtained by direct techniques (crystal blocking, X ray fission fragment) and nuclear techniques could be interpreted as evidence for nonexponential decays in nuclear systems

    Comments:
    17 pages, 1 figure
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1503.05346 [pdf]
    0 citations
  3. 03

    [Submitted on 17 Mar 2015] (cross-list from hep-ph)

    Collective flow in high-multiplicity proton-proton collisions

    Tigran Kalaydzhyan🇺🇸 · Edward Shuryak🇺🇸

    We present an evidence of strong radial flow in high-multiplicity pp collisions. We analyze the CMS data on the inclusive spectra of the charged pions, kaons and protons in the LHC TeV collisions. For we demonstrate the consistency of the hydrodynamic description with the (idealized) Gubser's flow. Using a one parameter fit of the model to experimental data, we obtain the initial fireball size to be of the order of 1 fm. At smaller multiplicities, the fit cannot be performed which shows a limitation of the hydrodynamic approach and provides us with falsifiability of our theory.

    Comments:
    5 pages
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    1503.05213 [pdf]
    PRC(2015)·35 citations
  4. 04

    [Submitted on 18 Mar 2015] (cross-list from nucl-ex)

    The electron screening puzzle and nuclear clustering

    C. Spitaleri · C.A. Bertulani · L. Fortunato · A. Vitturi

    Accurate measurements of nuclear reactions of astrophysical interest within, or close to, the Gamow peak, show evidence of an unexpected effect attributed to the presence of atomic electrons in the target. The experiments need to include an effective "screening" potential to explain the enhancement of the cross sections at the lowest measurable energies. Despite various theoretical studies conducted over the past 20 years and numerous experimental measurements, a theory has not yet been found that can explain the cause of the exceedingly high values of the screening potential needed to explain the data. In this letter we show that instead of an atomic physics solution of the "electron screening puzzle", the reason for the large screening potential values is in fact due to clusterization effects in nuclear reactions, in particular for reaction involving light nuclei.

    Comments:
    6 pages, 2 figures, accepted for publication in Physics Letters B
    Subjects:
    Nuclear Experiment (nucl-ex); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
    arXiv:
    1503.05266 [pdf]
    PLB(2016)·49 citations
  5. 05

    [Submitted on 18 Mar 2015] (cross-list from hep-ph)

    Lattice worldline representation of correlators in a background field

    Thomas Epelbaum🇨🇦 · Francois Gelis🇫🇷 · Bin Wu🇫🇷

    We use a discrete worldline representation in order to study the continuum limit of the one-loop expectation value of dimension two and four local operators in a background field. We illustrate this technique in the case of a scalar field coupled to a non-Abelian background gauge field. The first two coefficients of the expansion in powers of the lattice spacing can be expressed as sums over random walks on a d-dimensional cubic lattice. Using combinatorial identities for the distribution of the areas of closed random walks on a lattice, these coefficients can be turned into simple integrals. Our results are valid for an anisotropic lattice, with arbitrary lattice spacings in each direction.

    Comments:
    54 pages, 14 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    1503.05333 [pdf]
    JHEP(2015)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE