A Role of the Axial Vector Mesons on the Photon Production in Heavy Ion Collisions and Their Relevant Decays

A role of the axial vector mesons, such as $K_1$ and $a_1$, on the emitted photon spectrum in hot hadronic matter is studied through the channels $\pi \rho \to a_1 \to \pi \gamma$ and $K \rho \to K_1 \to K \gamma$. They are shown to be dominant channels in this spectrum. This study is carried out with an effective chiral lagrangian which includes vector and axial-vector mesons and explains well their relevant decays simultaneously.