Meson Towers and the Absence of Backward Peaks

Abstract

The absence of backward peaks in ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$, ${\ensuremath{\pi}}^{+}{K}^{\ensuremath{-}}$, ${K}^{+}{K}^{\ensuremath{-}}$, 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 ($\ensuremath{\omega},\ensuremath{\rho},{f}^{0},{A}_{2}$) master trajectory is presented. Consequences of a pure resonance picture of the low-energy $\overline{N}N$ elastic amplitude are explored.