Abstract
We use recently derived Ward identities and lattice data for the light- and strange-quark condensates to reconstruct the scalar and pseudoscalar susceptibilities ( χSκ , χPK ) in the isospin 1/2 channel. We show that χSκ develops a maximum above the QCD chiral transition, after which it degenerates with χPK . We also obtain χSκ within Unitarized Chiral Perturbation Theory (UChPT) at finite temperature, when it is saturated with the K0∗(700) (or κ ) meson, the dominant lowest-energy state in the isospin 1/2 scalar channel of πK scattering. Such UChPT result reproduces the expected peak structure, revealing the importance of thermal interactions, and makes it possible to examine the χSκ dependence on the light- and strange-quark masses. A consistent picture emerges controlled by the ml/ms ratio that allows one studying K - κ degeneration in the chiral, two-flavor and SU(3) limits. These results provide an alternative sign for O(4) × U(1)A restoration that can be explored in lattice simulations and highlight the role of strangeness, which regulated by the strange-quark condensate helps to reconcile the current tension among lattice results regarding U(1)A restoration.