**Global alpha-symmetries, hidden dimensions and QCD strings**

Dimitri Polyakov

Non-critical RNS superstring theory actions are invariant under the surprising set of global spacetime symmetries, called alpha-symmetries. These symmetries are realised non-linearly, mixing the matter and the ghost degrees of freedom. These symmetries are related to the presence of hidden spacetime dimensions and contain an SU(3) subgroup. Using the generators from this subgroup, we construct massless vertex operators for the octet of gluons in open string theory and show their scattering amplitudes to reproduce those of QCD in four dimensions. This leads to the gauge-string isomorphism between QCD observables and the special class of vertex operators in the self-adjoint representation of the alpha-symmetry group.