Can light Goldstone boson loops counter the `S-argument' against Technicolor?

Abstract

We examine the oblique correction phenomenology of one-family Technicolor with light pseudo-Goldstone bosons. From loop calculations based on a gauged chiral lagrangian for Technicolor, we are lead to conclude that even though loops with light Goldstone bosons give a negative contribution to $S$ measured at the $Z$-pole, this effect is not sufficiently large to unambiguously counter the `S-argument' against one-family Technicolor. This result cannot be guessed \apriori, but must be explicitly calculated. Our analysis entails an extended version of the $STU$ oblique parametrization of Peskin and Takeuchi. In principle, this extended formalism ($STUVWX$) must be used when there are light new particles in loops.

Comments: We have considerably shortened this paper. The bulk of the derivation of the $STUVWX$ formalism has been removed and will be presented elsewhere. More emphasis has been placed on the calculation of $STUVWX$ in a one-family Technicolor model with light psuedo-goldstone bosons. Though the result remains the same, the `S-argument' can not be countered, we have elucidated some interesting points in the calculation. In particular we emphasize the fact that it is not possible to tell from the outset what the calculated value of $S$ at the $Z$-pole will be