Hadron-Hadron collisions (1)
1. Structure functions (PDF): Fp(x,Q2) for q and g:
- MRS(T), CTEQ, ABFOW : Fitted to exp. DIS data
- Do not cover full xT. Large uncertainties in G(x) at high xT.
2. Fragmentation functions (FF): Dp/g,p(z,Q’2) for g and po:
- Chiapetta et al., Binnewies et al., … : Fitted to exp. e+e- data.
- Cover medium z domain and large scales. (Scarce e+e- data for large z, large uncertainties in the gluon fragmentation function).
3. Parton-parton (hard-scattering) sub-process:
- LO in as (Born) + (higher-order) K-factor: K(s,pT) = 1.5 - 2.5 (depends also on scale, next slide)
- NLO in as + phenomenological KT added to F(x,Q2) accounting for initial-state soft-gluon radiation (also seen in di-jet, di-muon, di-photon). (e.g. Lévai et al., Apanasevich et al., Wang)
- NLO in as + threshold-ressumation and recoil enhancements to account for soft radiation (Aurenche et al., Laenen et al.)