Vector Meson Dominance, Axial Anomaly and the Thermal behavior of $g_{ρωπ}(T)$

C. A. Dominguez, M. Loewe

Published 2000-08-23Version 1

By using a thermal Finite Energy QCD Sum Rule, we are able to establish the temperature dependence of the $g_{\omega \rho \pi}(T)$ strong coupling. It turns out that this coupling decreases as a function of temperature, vanishing at the critical temperature. This corresponds to a possible deconfining phenomenological signal. This result, together with the Vector Meson Dominance (VMD) expression for the amplitude $\pi ^{0} \to \gamma \gamma $, allows us to establish that this amplitude also vanishes at the critical temperature, in agreement with previous independent analysis. This results supports, once again, the validity of VMD at finite temperature. Several posssible scenarios are discussed. However, if VMD would not hold at finite temperature, then we will not be able to find a prediction for the thermal behavior of the $\pi ^{0} \to \gamma \gamma $ amplitude.