PRODUCTION OF HEAVY QUARKS AND HEAVY QUARKONIA

Uncertainties in the next-to-leading-order calculations of heavy-quark (Q) production are investigated. Predictions for total cross sections , single-inclusive distributions of heavy quarks and heavy flavoured h adrons, as well as for Q (Q) over bar correlations, are compared with charm and bottom data. The description of heavy-quarkonium production requires a separation of the short-distance scale of Q (Q) over bar pr oduction, which is set by the heavy-quark mass from the longer-distanc e scales associated with the bound-state formation. Various factorizat ion approaches are compared, in particular with respect to the differe nt constraints imposed on the colour and angular-momentum states of th e Q (Q) over bar pair(s) within a specific quarkonium state. Theoretic al predictions are confronted with data on heavy-quarkonium production at fixed-target experiments and also at p (p) over bar colliders, whe re fragmentation gives the leading-twist cross section in 1/p(T)(2) an d 1/m(2) at high transverse momentum.