Meson Towers and the Absence of Backward Peaks

Abstract

The absence of backward peaks in ${\pi }^{+}{\pi }^{-}$, ${\pi }^{+}{K}^{-}$, $K^{+}{K}^{-}$, and $\overline{N}N$ elastic scattering is speculatively associated with the existence of direct-channel exchange-degenerate towers of meson resonances. Experimental evidence for meson towers associated with a ($\omega ,\rho ,f^0,A_2$) master trajectory is presented. Consequences of a pure resonance picture of the low-energy $\overline{N}N$ elastic amplitude are explored.