Hunting for QCD strings in e+e−-annihilation

We develop a new mathematical method of extraction of nonperturbative corrections in QCD. The main attention is directed to the study of dimension 2 operator and its properties. The ordinary perturbation theory (PT) and analytical perturbation theory (APT) are used. The D-function is explored in dependence on both Q2 and Borel parameter M2. It is shown that the C2 coeffcient of the dimension 2 operator is negative and its compatibility to zero depends on choice of PT or APT and can vary in chosen ranges of M2. The strong (anti)correlation between C2 and gluon condensate found previously is confirmed