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T: Teilchenphysik
T 407: Higgs-Bosonen II
T 407.4: Vortrag
Mittwoch, 25. März 1998, 09:15–09:30, HS G
Gauge Invariant Effective Field Theory for a Heavy Higgs Boson — •A. Nyffeler1 and A. Schenk2 — 1DESY-Zeuthen, Platanenallee 6, 15738 Zeuthen — 2Ferdinand-Weiß-Straße 70, 79106 Freiburg
For large values of the Higgs boson mass the low energy structure of the gauged linear sigma model in the spontaneously broken phase can adequately be described by an effective field theory. Extending the method presented in Ref. [1] to the non-abelian case, we explicitly evaluate the corresponding effective Lagrangian from the underlying theory by matching the full and the effective theory at low energies. In gauge theories, there are, however, some subtleties involved when this matching is performed using gauge dependent Green’s functions [2]. These difficulties are overcome in our manifestly gauge invariant, functional approach by dealing only with gauge invariant Green’s functions. In view of the fact that effective Lagrangians have been widely used to parametrize effects of new physics beyond the Standard Model, it is crucial to use a well defined procedure to calculate the low-energy constants of the effective Lagrangian. Comparing these theoretical predictions with experimental constraints for the effective couplings might then enable one to distinguish between different underlying theories before direct effects become visible.
[1] A. Nyffeler and A. Schenk, Phys. Rev. D53, 1494, 1996
[2] D. Espriu and J. Matias, Phys. Lett. B341, 332, 1995