Publications (53)
The intrinsic charm contribution to the proton spin
M. V. Polyakov, A. Schaefer, O. V. Teryaev
The charm quark contribution to the first moment of is calculated using a heavy mass expansion of the divergence of the singlet axial current. It is shown to be small.
Prospects for Measuring Delta G from Jets at HERA with Polarized Protons and Electrons
A. De Roeck, J. Feltesse, F. Kunne +5
The measurement of the polarized gluon distribution function Delta G(x) from photon-gluon fusion processes in electron-proton deep inelastic scattering producing two jets has been…
QED in strong fields
A. Schaefer
We discuss the status of atomic physics in strong field. We focus on the problem of electron-positron lines observed in heavy-ion collisions and on QED effects, calculated in stron…
Cronin Effect in Hadron Production off Nuclei
B. Z. Kopeliovich, J. Nemchik, A. Schaefer +1
Recent data from RHIC for high- hadrons in gold-gold collisions raised again the long standing problem of quantitatively understanding the Cronin effect, i.e. nuclear enhancem…
Evolution Equations for Higher Moments of Angular Momentum Distributions
P. Haegler, A. Schaefer
Based on a sumrule for the nucleon spin we expand quark and gluon orbital angular momentum operators and derive an evolution matrix for higher moments of the corresponding distribu…
Sum rules for the T-odd fragmentation functions
A. Schaefer, O. V. Teryaev
The conservation of the intrinsic transverse momentum during parton fragmentation imposes non-trivial constraints on T-odd fragmentation functions. These significantly enhance the…