The V−A sum rules and the operator product expansion in complex q2-plane from τ-decay data Original Research Article

The operator product expansion (OPE) for the difference of vector and axial current correlators is analyzed for complex values of momentum q2. The vector and axial spectral functions, taken from hadronic τ-decay data, are treated with the help of Borel, gaussian and spectral moments sum rules. The range of applicability, advantages and disadvantages of each type are discussed. The general features of OPE are confirmed by the data. The vacuum expectation values of dimension-6 and -8 operators are found to be View the MathML source, View the MathML source.