New Metastable Charmonium and the ${\psi }^{\prime }$ Anomaly at CDF

Abstract

Production of metastable charmonium states more massive than the $\psi (3685)$ is expected in models and could be the source of up to $50\%$ of the $\psi$ observed at large $p_T$ at the Tevatron.Narrow $2^{-+},2^{--}c\bar{c}$ are predicted at around 3.8GeV and radially excited $2^3{P}_{1,2}$ may also have suppressed hadronic widths making these states potentially extra sources of $\psi (3685)$. Colour octet components are believed to dominate $\psi$ production at the Tevatron which suggests that hybrid charmonium production may also be prominent. Estimates of hybrid production rates and branching ratios into charmonium suggest that metastable hybrids with mass $\approx$ 4GeV may play an important role in generating the observed $\psi (3685),\psi (3095)$

Comments: 11 pages, no figures. RAL-94-093