Possible Exotic Exchange inpn→Δ−Δ++at6.98 GeVc

Abstract

The reaction $\mathrm{pn}\to {\Delta }^{-}{\Delta }^{++}$, where ${\Delta }^{-}$ is emitted in the forward direction in the c.m. system, is observed at $6.98 \frac{\mathrm{GeV}}{c}$ with a cross section of 0.09 ± 0.03 mb. The ratio between this reaction and the reaction $\mathrm{pn}\to {\Delta }^{++}{\Delta }^{-}$ with ${\Delta }^{++}$ in the forward direction in the c.m. system is found to be $\frac{\sigma \left({\Delta }^{++}{\Delta }^{-}\right)}{\sigma \left({\Delta }^{-}{\Delta }^{++}\right)}=12.2\mathrm{}\pm 4.5$. The ${\Delta }^{-}{\Delta }^{++}$ production is discussed in terms of exotic meson exchange and double meson exchange.