Polarization dependence of the $\varphi$ meson from finite-temperature QCD sum rules

Abstract

We study the $\varphi$ meson at finite temperature and finite momentum using QCD sum rules. The presence of medium breaks the Lorentz invariance, and induces distinct in-medium modifications of the transverse and longitudinal modes at finite momentum. We find that, with increasing momentum, the masses of both modes increase and a clear transverse--longitudinal splitting develops. The splitting is found to grow with temperature and to be mainly generated by the dimension-four spin-dependent thermal condensates.

15 pages, 5 figures