Evidence is presented that the production of ${\phi }^0$ mesons in ${\pi }^{+}p$ interactions at 16 GeV/c is dominated by conjoint mechanisms, i.e., ${\phi }^0$ mesons are accompanied by additional strange particles. For $x>\mathrm{}0.5\mathrm{}$, the cross sections for conjoint production of ${\phi }^0$ mesons are 0.37±0.16 μb with a ${\Lambda }^0$ hyperon and 0.33±0.15 μb with a $K_S^0$ meson. Assuming equal probability for each conjoint final state, the total conjoint production cross section is inferred to be 1.05±0.33 μb. This is to be compared with the inclusive ${\phi }^0$-meson production cross section of 1.3±2.0 μb in the same kinematic region. The data suggest that conjoint mechanisms are responsible for 81% of the ${\phi }^0$ production with a lower limit of 24% at the 94% confidence level.

• Received 29 September 1982

DOI:https://doi.org/10.1103/PhysRevD.27.1439