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Nuclear Theory·nucl-th

Tuesday·January 20, 2015

13 papers—9 primary·4 cross-listed

All13Primary9Cross-lists4
  1. 10

    [Submitted on 17 Jan 2015] (cross-list from hep-lat)

    Kenneth Wilson and lattice QCD

    Akira Ukawa🇯🇵

    We discuss the physics and computation of lattice QCD, a space-time lattice formulation of quantum chromodynamics, and Kenneth Wilson's seminal role in its development. We start with the fundamental issue of confinement of quarks in the theory of the strong interactions, and discuss how lattice QCD provides a framework for understanding this phenomenon. A conceptual issue with lattice QCD is a conflict of space-time lattice with chiral symmetry of quarks. We discuss how this problem is resolved. Since lattice QCD is a non-linear quantum dynamical system with infinite degrees of freedom, quantities which are analytically calculable are limited. On the other hand, it provides an ideal case of massively parallel numerical computations. We review the long and distinguished history of parallel-architecture supercomputers designed and built for lattice QCD. We discuss algorithmic developments, in particular the difficulties posed by the fermionic nature of quarks, and their resolution. The triad of efforts toward better understanding of physics, better algorithms, and more powerful supercomputers have produced major breakthroughs in our understanding of the strong interactions. We review the salient results of this effort in understanding the hadron spectrum, the Cabibbo-Kobayashi-Maskawa matrix elements and CP violation, and quark-gluon plasma at high temperatures. We conclude with a brief summary and a future perspective.

    Comments:
    52 pages, 16 figures, to appear in Journal of Statistical Physics
    Subjects:
    High Energy Physics — Lattice (hep-lat); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    1501.04215 [pdf]
    J.Statist.Phys.(2015)·23 citations
  2. 11

    [Submitted on 19 Jan 2015] (cross-list from nucl-ex)

    Search for {\eta}'(958)-nucleus bound states by (p,d) reaction at GSI and FAIR

    H. Fujioka🇯🇵 · Y. Ayyad🇯🇵 · J. Benlliure🇪🇸 · K.-T. Brinkmann🇩🇪 · S. Friedrich🇩🇪 · H. Geissel🇩🇪 · J. Gellanki🇳🇱 · C. Guo🇨🇳 · E. Gutz🇩🇪 · E. Haettner🇩🇪 · M.N. Harakeh🇳🇱 · R.S. Hayano🇯🇵 and 42 other authors

    The mass of the {\eta}' meson is theoretically expected to be reduced at finite density, which indicates the existence of {\eta}'-nucleus bound states. To investigate these states, we perform missing-mass spectroscopy for the (p, d) reaction near the {\eta}' production threshold. The overview of the experimental situation is given and the current status is discussed.

    Comments:
    6 pages, 3 figures; talk at II Symposium on applied nuclear physics and innovative technologies, September 24th - 27th, 2014, Jagiellonian University, Kraków Poland; to appear in Acta Physica Polonica B
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1501.04390 [pdf]
    Acta Phys.Polon.B(2015)·5 citations
  3. 12

    [Submitted on 19 Jan 2015] (cross-list from physics.atom-ph)

    Correlation Trends in the Hyperfine Structures of Fr

    B. K. Sahoo · D. K. Nandy · B. P. Das · Y. Sakemi

    We demonstrate the importance of electron correlation effects in the hyperfine structure constants of many low-lying states in Fr and Fr. This is achieved by calculating the magnetic dipole and electric quadrupole hyperfine structure constants using the Dirac-Fock approximation, second order many-body perturbation theory and the coupled-cluster method in the singles and doubles approximation in the relativistic framework. By combining our recommended theoretical results with the corresponding experimental values, improved nuclear magnetic dipole and electric quadrupole moments of the above isotopes are determined. In the present work, it is observed that there are large discrepancies between the hyperfine structure constants of the state obtained from the experimental and theoretical studies whereas good agreements are found for the other states. Our estimated hyperfine constants for the , , and states could be very useful as benchmarks for the measurement of these quantities.

    Comments:
    10 pages, 8 tables
    Subjects:
    Atomic Physics (physics.atom-ph); Nuclear Theory (nucl-th); Computational Physics (physics.comp-ph)
    arXiv:
    1501.04588 [pdf]
    PRA(2015)·22 citations
  4. 13

    [Submitted on 19 Jan 2015] (cross-list from hep-ph)

    Non-Global Logarithms, Factorization, and the Soft Substructure of Jets

    Andrew J. Larkoski🇺🇸 · Ian Moult🇺🇸 · Duff Neill🇺🇸

    An outstanding problem in QCD and jet physics is the factorization and resummation of logarithms that arise due to phase space constraints, so-called non-global logarithms (NGLs). In this paper, we show that NGLs can be factorized and resummed down to an unresolved infrared scale by making sufficiently many measurements on a jet or other restricted phase space region. Resummation is accomplished by renormalization group evolution of the objects in the factorization theorem and anomalous dimensions can be calculated to any perturbative accuracy and with any number of colors. To connect with the NGLs of more inclusive measurements, we present a novel perturbative expansion which is controlled by the volume of the allowed phase space for unresolved emissions. Arbitrary accuracy can be obtained by making more and more measurements so to resolve lower and lower scales. We find that even a minimal number of measurements produces agreement with Monte Carlo methods for leading-logarithmic resummation of NGLs at the sub-percent level over the full dynamical range relevant for the Large Hadron Collider. We also discuss other applications of our factorization theorem to soft jet dynamics and how to extend to higher-order accuracy.

    Comments:
    46 pages + appendices, 10 figures. v2: added current figures 4 and 5, as well as corrected several typos in appendices. v3: corrected some typos, added current figure 9, and added more discussion of fixed-order versus dressed gluon expansions. v4: fixed an error in numerics of two-dressed gluon; corrected figure 8, modified comparison to BMS. Conclusions unchanged. v5: fixed minor typo
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    1501.04596 [pdf]
    JHEP(2015)·151 citations

Affiliations

first authorsco-authorsvia INSPIRE