Quark helicity distributions in transverse momentum space and transverse coordinate space

Top Quark Transverse Momentum and Rapidity Distributions

Transverse momentum distributions for heavy quark pairs.

We study the transverse momentum distribution for a pair of heavy quarks produced in hadron-hadron interactions. Predictions for the large transverse momentum region are based on exact order αs QCD perturbation theory. For the small transverse momentum region, we use techniques for all orders resummation of leading logarithmic contributions associated with initial state soft gluon radiation. Th...

Charge Distributions in Transverse Coordinate Space and in Impact Parameter Space

We study the charge distributions of the valence quarks inside nucleon in the transverse coordinate space, which is conjugate to the transverse momentum space. We compare the results with the charge distributions in the impact parameter space. PACS numbers: 12.39.Ki, 13.40.Gp, 13.60.-r, 14.20.Dh ar X iv :0 80 5. 47 73 v1 [ he pph ] 3 0 M ay 2 00 8

Higgs Transverse-Momentum Resummation in Direct Space.

We propose a new approach to the resummation of the transverse-momentum distribution of a high-mass color-singlet system in hadronic collisions. The resummation is performed in momentum space and is free of kinematic singularities at small transverse momentum. We derive a formula accurate at the next-to-next-to-leading-logarithmic level, and present the first matched predictions to next-to-next...

Quark and Gluon Distributions in Coordinate Space †

In coordinate space, quark and gluon distributions of the nucleon are defined as correlation functions involving two field operators separated by a light-cone distance y = 2l. We study the nuclear modifications of these distributions. The largest effect is a strong depletion of parton distributions (shadowing) at large longitudinal distances, which starts for all parton species at l = 2 fm, i.e...