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Nuclear Theory·nucl-th

Monday·February 15, 2016

7 papers—4 primary·3 cross-listed

All7Primary4Cross-lists3
  1. 05

    [Submitted on 12 Feb 2016] (cross-list from hep-th)

    Mass Effect on Axial Charge Dynamics

    Er-dong Guo🇨🇳 · Shu Lin🇨🇳

    We studied effect of finite quark mass on the dynamics of axial charge using the D3/D7 model in holography. The mass term in axial anomaly equation affects both the fluctuation (generation) and dissipation of axial charge. We studied the dependence of the effect on quark mass and external magnetic field. For axial charge generation, we calculated the mass diffusion rate, which characterizes the helicity flipping rate. The rate is a non-monotonous function of mass and can be significantly enhanced by the magnetic field. The diffusive behavior is also related to a divergent susceptibility of axial charge. For axial charge dissipation, we found that in the long time limit, the mass term dissipates all the charge effectively generated by parallel electric and magnetic fields. The result is consistent with a relaxation time approximation. The rate of dissipation through mass term is a monotonous increasing function of both quark mass and magnetic field.

    Comments:
    22 pages, 5 figures
    Subjects:
    High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1602.03952 [pdf]
    PRD(2016)·19 citations
  2. 06

    [Submitted on 12 Feb 2016] (cross-list from physics.data-an)

    Modeling of critical experiments and its impact on integral covariance matrices and correlation coefficients

    Elisabeth Peters · Fabian Sommer · Maik Stuke

    In this manuscript we study the modeling of experimental data and its impact on the resulting integral experimental covariance and correlation matrices. By investigating a set of three low enriched and water moderated UO2 fuel rod arrays we found that modeling the same set of data with different, yet reasonable assumptions concerning the fuel rod composition and its geometric properties leads to significantly different covariance matrices or correlation coefficients. Following a Monte Carlo sampling approach, we show for nine different modeling assumptions the corresponding correlation coefficients and sensitivity profiles for each pair of the effective neutron multiplication factor keff. Within the 95% confidence interval the correlation coefficients vary from 0 to 1, depending on the modeling assumptions. Our findings show that the choice of modeling can have a huge impact on integral experimental covariance matrices. When the latter are used in a validation procedure to derive a bias, this procedure can be affected by the choice of modeling assumptions, too. The correct consideration of correlated data seems to be inevitable if the experimental data in a validation procedure is limited or one cannot rely on a sufficient number of uncorrelated data sets, e.g. from different laboratories using different setups etc.

    Comments:
    19 pages, 8 figures, Preprint submitted to Annals of Nuclear Energy
    Subjects:
    Data Analysis, Statistics and Probability (physics.data-an); Nuclear Theory (nucl-th)
    arXiv:
    1602.04038 [pdf]
    Annals Nucl.Energy(2016)·2 citations
  3. 07

    [Submitted on 12 Feb 2016] (cross-list from nucl-ex)

    INFN What Next: Ultra-relativistic Heavy-Ion Collisions

    A. Dainese🇮🇹 · E. Scomparin🇮🇹 · G. Usai🇮🇹 · P. Antonioli🇮🇹 · R. Arnaldi🇮🇹 · A. Beraudo🇮🇹 · E. Bruna🇮🇹 · G.E. Bruno🇮🇹 · S. Bufalino🇮🇹 · P. Di Nezza🇮🇹 · M.P. Lombardo🇮🇹 · R. Nania🇮🇹 and 129 other authors

    This document was prepared by the community that is active in Italy, within INFN (Istituto Nazionale di Fisica Nucleare), in the field of ultra-relativistic heavy-ion collisions. The experimental study of the phase diagram of strongly-interacting matter and of the Quark-Gluon Plasma (QGP) deconfined state will proceed, in the next 10-15 years, along two directions: the high-energy regime at RHIC and at the LHC, and the low-energy regime at FAIR, NICA, SPS and RHIC. The Italian community is strongly involved in the present and future programme of the ALICE experiment, the upgrade of which will open, in the 2020s, a new phase of high-precision characterisation of the QGP properties at the LHC. As a complement of this main activity, there is a growing interest in a possible future experiment at the SPS, which would target the search for the onset of deconfinement using dimuon measurements. On a longer timescale, the community looks with interest at the ongoing studies and discussions on a possible fixed-target programme using the LHC ion beams and on the Future Circular Collider.

    Comments:
    99 pages, 56 figures
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1602.04120 [pdf]
    Frascati Phys.Ser.(2016)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE