  An effective string theory emerging from the bilocal approximation to the
Method of Vacuum Correlators in gluodynamics is shown to be well described by
the 4D theory of the massive Abelian Kalb-Ramond field interacting with the
string, which is known to be the low-energy limit of the Universal Confining
String Theory. The mass of the Kalb-Ramond field in this approach plays the
role of the inverse correlation length of the vacuum, and it is shown that in
the massless limit string picture disappears. The background field method,
known in the theory of nonlinear sigma models, is applied to derivation of the
effective action, quadratic in quantum fluctuations around a given (e.g.
minimal) string world-sheet.
