Charm-Anticharm Asymmetries in High Energy Photoproduction
by P.L. Frabetti et al.
Abstract: We report measurements of charm particle production asymmetries from the Fermilab photoproduction experiment E687. An asymmetry in the rate of production of charm versus anticharm particles is expected to arise primarily from fragmentation effects. We observe statistically significant asymmetries in the photoproduction of $D^+$, $D^{*+}$ and $D^0$ mesons and find small (but statistically weak) asymmetries in the production of the $D_s^+$ meson and the $\Lambda_c^+$ baryon. Our inclusive photoproduction asymmetries are compared to predictions from nonperturbative models of charm quark fragmentation.