Utilizing recent DIS measurements (Ïƒr, 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 radiativelyâ€¦ (More)

Polarized deep inelastic scattering (DIS) data are analyzed in leading and nextâ€“toâ€“ leading order of QCD within the common â€˜standardâ€™ scenario of polarized parton distributions with aâ€¦ (More)

Dynamical parton densities, generated radiatively from valenceâ€“like inputs at some low resolution scale, are confronted with recent smallâ€“x data on deep inelastic and other hard scattering processes.â€¦ (More)

Predictions of isospin asymmetries of valence and sea distributions are presented which are generated by QED leading Oalpha photon bremsstrahlung effects. Together with isospin violations arisingâ€¦ (More)

Utilizing recent DIS measurements (F2,L) and data on dilepton and highâ€“ET jet production we determine the dynamical parton distributions of the nucleon generated radiatively from valenceâ€“likeâ€¦ (More)

We compare â€˜fixed flavor number schemeâ€™ (FFNS) and â€˜variable flavor number schemeâ€™ (VFNS) parton model predictions at high energy colliders. Based on our recent LOâ€“ and NLOâ€“FFNS dynamical partonâ€¦ (More)

The implications of the positivity constraint, |g Î³(P 2) 1 (x,Q 2)| â‰¤ F Î³(P 2) 1 (x,Q 2), on the presently unknown spinâ€“dependent structure function g Î³(P 2) 1 (x,Q 2) of real and virtual photons areâ€¦ (More)

The implications of the positivity constraint on the presently unknown polarized structure function of the photon, g 1 (x,Q 2), are studied in detail. In particular the nonâ€“trivial consequences ofâ€¦ (More)

Using constituent quark model constraints we calculate the gluon and seaâ€“quark content of pions solely in terms of their valence density (fixed by Ï€N Drellâ€“Yan data) and the known sea and gluonâ€¦ (More)

The leading order vacuum polarization contribution of very light milliâ€“charged fermions with charge Îµe and mass Î¼ to the Lamb shift of the hydrogen atom is shown to imply a universal, i.e.â€¦ (More)