Resummation of the hadronic tau decay width with the modified Borel transform method - art. no. 093016

A modified Borel transform of the Adler function is used to resum the hadro nic tau decay width ratio. In contrast with the ordinary Borel transform, t he integrand of the Borel integral is renormalization-scale invariant. We u se an ansatz which explicitly accounts for the structure of the leading inf rared renormalon. Further, we use judiciously chosen conformal transformati ons for the Borel variable, in order to map sufficiently away from the orig in the other ultraviolet and infrared renormalon singularities. In addition , we apply Pade approximants for the corresponding truncated perturbation s eries of the modified Borel transform, in order to further accelerate the c onvergence. Comparing the results with the presently available experimental data on the tau hadronic decay width ratio, we obtain alpha (s)(M-z(2)) = 0.1192 +/-0.0007(exp)+/-0.0010(EW+CKM)+/-0.0009(th.)+/-0.0003(evol.). These predictions virtually agree with those of our previous resummations where we used ordinary Borel transforms instead.