Alexander Laschka

Technische Universität München, München, Bavaria, Germany

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Publications (5)4.57 Total impact

  • Source
    Alexander Laschka, Norbert Kaiser, Wolfram Weise
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    ABSTRACT: Central and spin-spin potentials for charmonium, constructed from Nambu-Bethe-Salpeter amplitudes in lattice simulations of full QCD, are matched with results from perturbative QCD at an appropriate distance scale. This matching is made possible by defining the perturbative potentials through Fourier transforms with a low-momentum cutoff. The central (spin-independent) potential is compared with potentials derived from an expansion in powers of the inverse quark mass. A well-controlled continuation of the charmonium spin-spin potential from lattice QCD to short distances is performed. The mass splittings of the charmonium singlet and triplet states below the open charm threshold, obtained from the matched spin-spin potential, are in good agreement with the experimental values.
    Physics Letters B 05/2012; 715(s 1–3). · 4.57 Impact Factor
  • Source
    Alexander Laschka, Norbert Kaiser, Wolfram Weise
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    ABSTRACT: The heavy quark-antiquark potential is accessible in perturbative QCD and in lattice simulations. The perturbative short-distance part of the potential is contructed via a restricted Fourier transform, covering the momentum region where perturbative QCD is applicable. We show that for the leading order static term as well as for the mass dependent corrections, the perturbative part can be matched at intermediate distances with results from lattice QCD. From these matched potentials, quarkonium spectra with a single free parameter (the heavy quark mass) are derived and compared with empirical spectra. Furthermore, charm and bottom quark masses are deduced.
    08/2011;
  • A. Laschka, N. Kaiser, W. Weise
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    ABSTRACT: The heavy quark-antiquark potential is an important topic in QCD that involves perturbative as well as non-perturbative methods. We construct the perturbative short-distance part of the potential in coordinate space via a subtracted Fourier transform, covering the momentum region where perturbative QCD is applicable. This potential is matched at intermediate distances to the non-perturbative long distance part from lattice QCD simulations. In addition to the static potential, quark mass dependent contributions and their effects on the quarkonium spectrum are discussed. Furthermore we derive charm and bottom quark masses in this approach.
    05/2011;
  • Source
    Alexander Laschka, Norbert Kaiser, Wolfram Weise
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    ABSTRACT: An updated heavy quark-antiquark potential is constructed by matching the short-distance perturbative part to long-distance lattice QCD results at an intermediate r scale. The static potential and the order 1/m potential are both analyzed in this way. Effects if order 1/m in charmonium and bottomonium spectra are discussed in comparison. Charm and bottom quark masses are deduced from the spectra and related to the quark masses of other schemes.
    Physical review D: Particles and fields 02/2011; 83(9).
  • Source
    Alexander Laschka, Norbert Kaiser, Wolfram Weise
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    ABSTRACT: The heavy quark-antiquark potential in perturbative QCD is subject to ambiguities. We show how to derive a well-defined and stable short-distance potential that can be matched to results from lattice QCD simulations at intermediate distances. The static potential as well as the order 1/m potential are discussed. Comment: 2 pages, 2 figures, Proceedings of the 8th Conference on Quark Confinement and the Hadron Spectrum, September 1-6, 2008, Mainz, Germany
    01/2009;

Publication Stats

12 Citations
4.57 Total Impact Points

Institutions

  • 2011–2012
    • Technische Universität München
      • Faculty of Physics
      München, Bavaria, Germany