Error estimates on parton density distributions

Parton Distributions

I present an overview of some current topics in the measurement of Parton Distribution Functions.

Parton Distributions : Experimental aspects

Unintegrated parton distributions

We describe how to calculate the parton distributions fa(x, k 2 t , μ 2), unintegrated over the parton transverse momentum kt, from auxiliary functions ha(x, k 2 t ), which satisfy single-scale evolution equations. The formalism embodies both DGLAP and BFKL contributions, and accounts for the angular ordering which comes from coherence effects in gluon emission. We check that the unintegrated d...

Off-Forward Parton Distributions

Recently, there have been some interesting developments involving offforward parton distributions of the nucleon, deeply virtual Compton scattering, and hard diffractive vector-meson production. These developments are triggered by the realization that the off-forward distributions contain information about the internal spin structure of the nucleon and that diffractive electroproduction of vect...

Dynamical NNLO parton distributions

Utilizing recent DIS measurements (σr, F2,3,L) and data on hadronic dilepton production we determine at NNLO (3-loop) of QCD the dynamical parton distributions of the nucleon generated radiatively from valencelike positive input distributions at an optimally chosen low resolution scale (Q0 < 1 GeV 2). These are compared with ‘standard’ NNLO distributions generated from positive input distributi...