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Few-Body Systems

, Volume 52, Issue 3–4, pp 397–401 | Cite as

Form Factors of Few-Body Systems: Point Form Versus Front Form

  • M. Gómez-RochaEmail author
  • E. P. Biernat
  • W. Schweiger
Article

Abstract

We present a relativistic point-form approach for the calculation of electroweak form factors of few-body bound states that leads to results which resemble those obtained within the covariant light-front formalism of Carbonell et al. (Phys. Rep. 300:215–347, 1998). Our starting points are the physical processes in which such form factors are measured, i.e. electron scattering off the bound state, or the semileptonic weak decay of the bound state. These processes are treated by means of a coupled-channel framework for a Bakamjian–Thomas type mass operator. A current with the correct covariance properties is then derived from the pertinent leading-order electroweak scattering or decay amplitude. As it turns out, the electromagnetic current is affected by unphysical contributions which can be traced back to wrong cluster properties inherent in the Bakamjian–Thomas construction. These spurious contributions, however, can be separated uniquely, as in the covariant light-front approach. In this way we end up with form factors which agree with those obtained from the covariant light-front approach. As an example we will present results for electroweak form factors of heavy–light systems and discuss the heavy-quark limit which leads to the famous Isgur–Wise function.

Keywords

Form Factor Vertex Operator Pseudoscalar Meson Electromagnetic Current Wise Function 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    Keister B.D., Polyzou W.N.: Relativistic Hamiltonian dynamics in nuclear and particle physics. Adv. Nucl. Phys. 20, 225 (1991)Google Scholar
  2. 2.
    Carbonell J., Desplanques B., Karmanov V.A., Mathiot J.F.: Explicitly covariant light front dynamics and relativistic few body systems. Phys. Rep. 300, 215–347 (1998)MathSciNetADSCrossRefGoogle Scholar
  3. 3.
    Bakamjian B., Thomas L.H.: Relativistic particle dynamics. 2. Phys. Rev. 92, 1300 (1953)MathSciNetADSzbMATHCrossRefGoogle Scholar
  4. 4.
    Klink W.H.: Constructing point form mass operators from vertex interactions. Nucl. Phys. A 716, 123 (2003)ADSzbMATHCrossRefGoogle Scholar
  5. 5.
    Klink W.H.: Relativistic simultaneously coupled multiparticle states. Phys. Rev. C 58, 3617 (1998)ADSCrossRefGoogle Scholar
  6. 6.
    Biernat E.P., Schweiger W., Fuchsberger K., Klink W.H.: Electromagnetic meson form factor from a relativistic coupled-channel approach. Phys. Rev. C 79, 055203 (2009)ADSCrossRefGoogle Scholar
  7. 7.
    Biernat, E.P.: Electromagnetic properties of few-body systems within a point-form approach. PhD thesis, Karl-Franzens-Universität Graz (2011)Google Scholar
  8. 8.
    Gómez-Rocha, M., Schweiger, W.: Electroweak form factors of heavy–light mesons—a relativistic point-form approach (in preparation)Google Scholar
  9. 9.
    Isgur, N., Wise, M.B.: Weak decays of heavy mesons in the static quark approximation. Phys. Lett. B 232, 113 (1989); 237, 527 (1990)Google Scholar
  10. 10.
    Cheng H.Y., Cheung C.Y., Hwang C.W.: Mesonic form factors and the Isgur-Wise function on the light-front. Phys. Rev. D 55, 1559 (1997)ADSCrossRefGoogle Scholar
  11. 11.
    Neubert M.: Heavy quark symmetry. Phys. Rep. 245, 259 (1994)ADSCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  1. 1.Institut für Physik, FB Theoretische PhysikUniversität GrazGrazAustria
  2. 2.Departamento de Física and Centro de Física Teórica de PartículasInstituto Superior Técnico, Universidade Técnica de LisboaLisboaPortugal

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