AB collisions
Nuclear thickness function TA(b) :
- TA(b) : number of nucleons/transverse area at impact parameter b
- PDFs factorized as: FiA (x,Q2,b) ? [FiA (x,Q2) ] TA(b)
- TAA(b) : number of NN collisions/transv. area at b related to the nuclear density (sharp sphere or gaussian nucleus parametrizations)
Parton energy loss (“jet quenching”):
- Multiple final-state gluon radiation off the produced hard parton traversing the (dense) medium:
- Coherent (LPM) and incoherent regimes depend on DL (medium length).
- Energy-loss is outside jet cone (and jets are more collimated ...)
- dE/dx in the QGP = [energy loss/scatt.] / [parton mean free path] = e / l = 2 - 4 Gev/fm
- Observables: i) Quenching of leading-particle inclusive pT spectra and ii) photon-tagged jets.
- Modified FFs: Phenomenological approach to take into account medium-induced energy loss. (Wang, Jalinian ...)
Collective flow can also affect inclusive particle spectra ...