Lower bound to the pion polarizability from QCD sum rules

Making use of QCD sum rules a lower bound is found which relates the electromagnetic polarizability αE and mean-square radius 〈rπ2〉 of charged pions through the intrinsic polarizability αE = αE − α〈rπ2〉(3Mπ). We find that if present constraints on the QCD continuum (duality) threshold are accepted, this lower bound on the intrinsic polarizability αE is incompatible with some previous determinations of αE and 〈rπ2〉.