Universality class of confining strings

A recently proposed model of confining strings has a non-local world-sheet action induced by a space-time Kalb–Ramond tensor field. Here we show that, in the large-D approximation, an infinite set of ghost- and tachyon-free truncations of the derivative expansion of this action all lead to c=1 models. Their infrared limit describes smooth strings with world-sheets of Hausdorff dimension DH=2 and long-range orientational order, as expected for QCD strings.