Comparison of High-Transverse-Momentum ${\pi }^0$ Production from ${\pi }^{-}$, $K^{-}$, $p$, and $\overline{p}$ Beams

We compare high-transverse-momentum ($P_{\perp }$) inclusive ${\pi }^0$ production from ${\pi }^{-}$, $K^{-}$, $p$, and $\overline{p}$ beams, at 100 and 200 GeV/c, for center-of-mass (c.m.) angles ranging from 2° to 115° and $P_{\perp }<4.5\mathrm{}$ GeV/c. The ratio $\frac{\sigma (pp\to {\pi }^{0}X)}{\sigma (\pi p\to {\pi }^{0}X)}$ decreases with increasing $P_{\perp }$, and changes dramatically with c.m. angle. Also, the ratios $\frac{\sigma (K^{-}p\to {\pi }^{0}X)}{\sigma ({\pi }^{-}p\to {\pi }^{0}X)}$ and $\frac{\sigma (\overline{p}p\to {\pi }^{0}X)}{\sigma (pp\to {\pi }^{0}X)}$ are approximately constant. These measurements are consistent with a theoretical viewpoint in which constituents of the incident hadrons undergo a hard-scattering subprocess.