Advertisement

Baryon chiral perturbation theory in manifestly Lorentz invariant form

  • T. Becher
  • H. Leutwyler
Theoretical physics

Abstract.

We show that in the presence of massive particles, such as nucleons, the standard low-energy expansion, in powers of meson momenta and light-quark masses, in general converges in only part of the low-energy region. The expansion of the scalar form factor \(\sigma(t)\), for instance, breaks down in the vicinity of \(t=4M_\pi^2\). In the language of heavy baryon chiral perturbation theory, the proper behaviour in the threshold region results only if the multiple internal-line insertions generated by relativistic kinematics are summed up to all orders. We propose a method that yields a coherent representation throughout the low-energy region, while keeping Lorentz and chiral invariance explicit at all stages. The method is illustrated with a calculation of the nucleon mass and of the scalar form factor to order \(p^4\).

Keywords

Perturbation Theory Massive Particle Invariant Form Chiral Perturbation Theory Threshold Region 
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.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • T. Becher
    • 1
  • H. Leutwyler
    • 1
  1. 1. Institute for Theoretical Physics, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland CH

Personalised recommendations