A1-Nucleon Cross Section from Coherent Production in Nuclei

Comparison of $A_1$ coherent production in Freon with production in ${\mathrm{H}}_2$ implies a total $A_1$-nucleon cross section $\sigma \left(A_{1}N\right)<~\left({0.5}_{-0.2\mathrm{}}^{+0.3\mathrm{}}\right)\sigma \left(\pi N\right)$ with a further theoretical uncertainty of about 10%. The result appears to preclude the possibility, suggested by the Deck model, that the $\rho$ and $\pi$ in the $A_1$ are produced close together without appreciable interaction between them.