Experimental Evidence for a High-Mass Vector Meson

Abstract

We have measured the cross section for the reaction $\overline{p}p\to K_S^{}{}_{}{}^{0}K_L^{}{}_{}{}^0$ from 100-800 MeV/c. A significant enhancement in the cross section is observed at a mean momentum of 600 MeV/c. A Legendre-polynomial analysis of the angular distributions also shows an enhancement in the $A_2$ coefficient in the same momentum range. A plausible explanation of the data indicates a new meson state $\rho \mathrm{}\left(1970\right)\mathrm{}$ with a mass $M=1968\mathrm{}$ MeV, width $\Gamma =35\mathrm{}$ MeV, and $J^{\mathrm{PC}}=1^{--}$.