  We perform a finite energy sum rule analysis of the flavor ud two-point V-A
current correlator, Delta Pi (Q^2). The analysis, which is performed using both
the ALEPH and OPAL databases for the V-A spectral function, Delta rho, allows
us to extract the dimension six V-A OPE coefficient, a_6, which is related to
the matrix element of the electroweak penguin operator, Q_8, by chiral
symmetry. The result for a_6 leads directly to the improved (chiral limit)
determination epsilon'/epsilon = (- 15.0 +- 2.7) 10^{-4}. Determination of
higher dimension OPE contributions also allows us to perform an independent
test using a low-scale constrained dispersive analysis, which provides a highly
nontrivial consistency check of the results.

High Energy Physics - Phenomenology