Using a manifestly gauge-invariant approach we show that the set of
low-energy constants in the electroweak chiral Lagrangian currently used in the
literature is redundant. In particular, by employing the equations of motion
for the gauge fields, one can choose to remove two low-energy constants which
contribute to the self-energies of the gauge bosons. The relation of this
result to the experimentally determined values for the oblique parameters S,T
and U is discussed. We then evaluate the matching relation between
gauge-invariant Green's functions in the full and the effective theory for the
case of the Standard Model with a heavy Higgs boson and compare the results for
the independent low-energy constants with those for a simple Technicolor model.
Since the pattern of the low-energy constants is very different in these two
models it may be misleading to mimic any strongly interacting symmetry breaking
sector by a heavy Higgs boson. From our investigation we conclude that current
electroweak precision data do not really rule out such strongly interacting
models.Comment: 10 pages, Latex. Based on talks presented at the Linear Collider
Workshop, Oxford, 20-23 March 1999 and at the International Symposium
Ahrenshoop, Buckow, Germany, 23-28 August 1999. To appear in the Proceedings
of the 2nd ECFA/DESY Study on Physics Studies for a Future Linear Collider.
v2: one sign in Table 1 and some typos corrected; some comments added in
Section 5; Conclusions unchange
