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Nuclear Theory·nucl-th

Monday·September 25, 2017

3 papers—3 primary·0 cross-listed

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  1. 01

    [Submitted on 21 Sept 2017]

    High precision analytical description of the allowed spectrum shape

    Leendert Hayen🇧🇪 · Nathal Severijns🇧🇪 · Kazimierz Bodek🇵🇱 · Xavier Mougeot🇵🇱 · Dagmara Rozpedzik🇫🇷

    A fully analytical description of the allowed spectrum shape is given in view of ongoing and planned measurements. Its study forms an invaluable tool in the search for physics beyond the standard electroweak model and the weak magnetism recoil term. Contributions stemming from finite size corrections, mass effects, and radiative corrections are reviewed. A particular focus is placed on atomic and chemical effects, where the existing description is extended and analytically provided. The effects of QCD-induced recoil terms are discussed, and cross-checks were performed for different theoretical formalisms. Special attention was given to a comparison of the treatment of nuclear structure effects in different formalisms. Corrections were derived for both Fermi and Gamow-Teller transitions, and methods of analytical evaluation thoroughly discussed. In its integrated form, calculated values were in agreement with the most precise numerical results within the aimed for precision. We stress the need for an accurate evaluation of weak magnetism contributions, and note the possible significance of the oft-neglected induced pseudoscalar interaction. Together with improved atomic corrections, we then present an analytical description of the allowed spectrum shape accurate to a few parts in down to 1\,keV for low to medium nuclei, thereby extending the work by previous authors by nearly an order of magnitude.

    Comments:
    Accepted for Reviews of Modern Physics
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1709.07530 [pdf]
    RMP(2018)·132 citations
  2. 02

    [Submitted on 22 Sept 2017]

    Multiplicity fluctuation and correlation of mesons and baryons in ultra-relativistic heavy-ion collisions at LHC

    Hai-hong Li🇨🇳 · Feng-lan Shao🇨🇳 · Jun Song🇨🇳

    We study the multiplicity fluctuation and correlation of identified mesons and baryons formed at the hadronization by the quark combination mechanism in the context of ultra-relativistic heavy-ion collisions. Based on the statistical method of free quark combination, we derive the two-hadron multiplicity correlations such as meson-meson and meson-baryon correlations, and take the effects of quark number fluctuation at hadronization into account by a Taylor expansion method. After including the decay contributions, we calculate the dynamical fluctuation observable for , and pairs and discuss what underlying physics can be obtained by comparing with the data in Pb-Pb collisions at TeV and the simulations from HIJING and AMPT event generators.

    Comments:
    8 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1709.07582 [pdf]
    CPC(2018)·2 citations
  3. 03

    [Submitted on 22 Sept 2017]

    Magnetic Dipole Transitions with the Full Skyrme Interaction

    M. C. Barton · P. D. Stevenson

    The purpose of this paper is to investigate the use of the TDHF method with different Skryme force interactions for the prediction of the M1 strength function associated with Cr, in particular due to the tensor part of the Skyrme force.Cr was chosen due to the recent interest experimentally in this nucleus and the clear data avaliable for comparison. The method used involves applying an instantaneous boost to the wavefunction at the beginning of the dynamical calculations in order to initiate a broadband excitation of the nucleus, following which a Fourier analysis is made. The results of the TDHF simulation found broad agreement with experiment for the range of energies which excite an M1 transition for a variety of forces. The tensor terms appear to be important in qualitatively changing the details of the strength distribution in the main part of the strength function between around 8 and 12 MeV.

    Comments:
    8 pages, 2 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1709.07823 [pdf]
    1 citation

Affiliations

first authorsco-authorsvia INSPIRE