QCD radiative corrections to $χ_{cJ}$ production at hadron colliders

Yan-Qing Ma; Kai Wang; K. Chao

Paper

QCD radiative corrections to $χ_{cJ}$ production at hadron colliders

Abstract

To clarify the outstanding problem in charmonium production that existing theories cannot explain the observed cross sections of

(J=0,1,2) and ratio

(in contrast to the spin counting value 5/3) at the Tevatron, we study the complete next-to-leading order radiative corrections in nonrelativistic QCD, and find next-to-leading order contributions of

are more important than leading order at high

, and

decreases slower than

, implying a natural explanation for the

puzzle. By fitting

, the predicted cross sections of

are found to agree with data. The result indicates color-octet contribution is crucially needed, thus providing a unique test for heavy quarkonium production mechanisms. Feed-down contributions of

to prompt

production are estimated to be substantial, about

GeV. Production of

(J=0,1,2) at the LHC is also predicted.