Gorazd Cvetič, Cristián Villavicencio
We apply a recently constructed model of analytic QCD in the Operator Product Expansion (OPE) analysis of the tau lepton decay data in the V+A channel. While the model has the running coupling A(Q^2) with no unphysical singularities (i.e., it is analytic), it differs from the corresponding perturbative QCD coupling a(Q^2) at high squared momenta Q^2 by terms proportional to (1/Q^2)^5. This implies that it does not contradict the ITEP OPE philosophy and can be consistently applied with OPE up to terms of dimension D=8. In evaluations for the Adler function we use a Pade-related renormalization-scale-independent resummation, applicable in any analytic QCD model. Applying the Borel sum rules in the Q^2 plane along rays and comparing with ALEPH data, we obtain the gluonic condensate values < (alpha_s/pi) G^2 > = 0.005 +/- 0.007 GeV^4. Consideration of the D=6 term gives us marginal consistency of the model with the zero value of the condensate alpha_s ^2. On the other hand, in perturbative QCD in MSbar scheme we deduce almost the same results for the gluon condensate, but the deduced value of the D=6 condensate alpha_s ^2 is negative and thus signalling a possible inconsistency in this case.
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http://arxiv.org/abs/1209.2953
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