S. Fleming et I. Maksymyk, EXTENDING THE STU FORMALISM FOR ELECTROWEAK OBLIQUE CORRECTIONS TO THE CASE OF LIGHT NEW PHYSICS, Annals of physics, 251(1), 1996, pp. 26-44
The STU formalism, which parametrizes oblique electroweak corrections
due to heavy new physics, has recently been extended to the case of li
ght new physics. In principle, this extended formalism, which involves
the six parameters STUVWX, must be used if loop contributions to the
oblique corrections entail light new particles with masses in the rang
e similar to M(Z) or less. Applying classical equations of motion to m
anipulate the effective lagrangian, we present here a thorough introdu
ctory discussion of the STUVWX formalism, elucidating such subtleties
as the connection between S - X and the star formalism of Kennedy and
Lynn, the connection between S - X, and the epsilon parameters of Alta
relli and Barbieri, and the loss of definite symmetry properties which
S and U undergo as the STU parameter set is extended to the case of l
ight new physics. This paper provides a significantly more detailed, e
xpanded, and pedagogic presentation than previous expositions of the S
TUVWX parameters. (C) 1996 Academic Press, Inc.