Exotic four-quark bar u bar usd mesons and QCD sum rules

In connection with recent reports of the discovery of exotic meson resonances with a mass of ∼3.1 GeV we attempt to estimate their most likely quantum numbers by means of an investigation of the correlation functions of two four-quark currents in the framework of QCD sum rules. We observe a remarkable splitting between channels with different quantum numbers similar to the previously observed splitting for hybrid q bar qG states. In the channels with J P=0+ and 1- the correlation functions suggest a comparatively large mass scale