Charge balance functions in a scenario of continuing charge production in quark matter

Abstract

We study the charge balance functions of $ \pi^{+}\pi^{-}$ and $K^{+}K^{-}$ in a scenario of continuing charge creation in a strongly interacting quark-gluon plasma (QGP) in high-energy heavy-ion collisions, using relativistic hydrodynamics and the lattice QCD results of quark susceptibilities and the equation of state of the QGP. We find that the charge balance functions are dominated by their QGP components because most charges are produced before the hadronic stage. The hadronic component of the balance function of $ \pi^{+}\pi^{-}$ is small but non-negligible. The balance function of $ K^{+}K^{-}$ has a negative hadronic component because the strangeness decreases during the system evolution. The correlation between light and strange quarks leads to small enhancements of the balance functions at small rapidity difference.