We estimate the splitting between the spatial correlation lengths in the scalar and pseudoscalar channels in QCD at high temperature. The splitting is due to the contribution of the instanton/anti-instanton chains in the thermal ensemble, even though instanton contributions to thermodynamic quantities are suppressed. The splitting vanishes at asymptotically high temperatures as $\Delta M/M\propto (\Lambda_{ QCD}/T)^b$, where $b$ is the beta function coefficient.
Categories: hep-ph hep-lat hep-th