Higher excitations of $\omega$ and $\varphi$ in dilepton spectra

Abstract

We consider lepton pair production via two-hadron annihilation through various isoscalar vector mesons within hot, baryon-free matter. This is tantamount to constructing effective form factors which we model using a vector-meson-dominance approach and compare with experiment. In particular, we consider the reactions $\pi \rho \to e^{+}{e}^{-}$ and $\bar{K}{K}^{\ast }(892)$ + c.c. $\to e^{+}{e}^{-}$. We find that $\omega (1390)$ and $\varphi (1680)$ are visible in the mass spectrum for the thermal production rate above the ${\pi }^{+}{\pi }^{-}\to e^{+}{e}^{-}$ tail and even above the $\pi a_1\to e^{+}{e}^{-}$ results---both of which were considered important in their respective mass regions.

Comments: RevTeX, 9 pages, 6 (uuencoded) figures; to appear in Phys. Rev D