Fragmentation production of J/psi and psi' at the Tevatron

Abstract

We present a calculation of the charm and gluon fragmentation contributions to inclusive $J/ψ$ and $ψ'$ production at large transverse momentum at the Tevatron. For $ψ$ production, we include both fragmentation directly into $ψ$ and fragmentation into $χ_c$ followed by the radiative decay $χ_c \to ψ+ γ$. We find that fragmentation overwhelms the leading-order mechanisms for prompt $ψ$ production at large $p_T$, and that the dominant contributions come from fragmentation into $χ_c$. Our results are consistent with recent data on $ψ$ production from the CDF and D0 experiments. In the case of prompt $ψ'$ production, the dominant mechanism at large $p_T$ is charm fragmentation into $ψ'$. We find serious disagreement between our theoretical predictions and recent $ψ'$ data from the Tevatron.