Gluon fragmentation into polarized charmonium

Abstract

Gluon fragmentation to $\text{chicJ}(1P)$ followed by single photon emission represents the dominant source of prompt $J/\Psi$'s at the Tevatron for $p_{\perp }\text{gtap}6\text{GeV}$. Since fragmenting gluons are approximately transverse, their products are significantly polarized. We find that gluon fragmentation populates the helicity levels of $\text{chione}$, $\text{chitwo}$ and $J/\Psi$ according to $D_{{\text{chione}}^{(h=0)}}:D_{{\text{chione}}^{(|h|=1)}}\simeq 1:1$, $D_{{\text{chitwo}}^{(h=0)}}:D_{{\text{chitwo}}^{(|h|=1)}}:D_{{\text{chitwo}}^{(|h|=2)}}\simeq 1:2.9:6.0$ and $D_{{\text{J}}^{(h=0)}}:D_{{\text{J}}^{(|h|=1)}}\simeq 1:3.4$. We also speculate that gluon fragmentation to the radially excited $\text{chitwo}(2P)$ state followed by subsequent radiative decay could represent a large source of ${\psi }^{\prime }(2S)$'s and potentially resolve the ${\psi }^{\prime }$ deficit problem. A measurement of these states' polarizations would test this idea.

Comments: 11 pages with 1 uuencoded figure, CALT-68-1943, FERMILAB-PUB-94/256-T