Light scalar susceptibilities and the ${\pi }^0-\eta$ mixing

Abstract

We have performed a thermal analysis of the light scalar susceptibilities in the context of SU(3)-Chiral Perturbation Theory to one loop taking into account the QCD source of isospin breaking (IB), i.e corrections coming from $m_u\ne m_d$. We find that the value of the connected scalar susceptibility in the infrared regime and below the critical temperature is entirely dominated by the ${\pi }^0-\eta$ mixing, which leads to model-independent $\mathcal{O}({ϵ}^0)$ corrections, where $ϵ\sim m_d-m_u$, in the combination ${\chi }_{uu}-{\chi }_{ud}$ of flavour breaking susceptibilities.

Comments: Proceedings of the "Quark Confinement and Hadron Spectrum IX", Madrid, Spain, August 30th-September 3rd 2010. 3 pages, 2 figures. AIP Proceedings style