Paper
Parton distributions incorporating QED contributions
Authors
A. D. Martin, R. G. Roberts, W. J. Stirling, R. S. Thorne
Abstract
We perform a global parton analysis of deep inelastic and related hard-scattering data, including corrections to the parton evolution. Although the quality of the fit is essentially unchanged, there are two important physical consequences. First, the different DGLAP evolution of u and d type quarks introduces isospin violation, i.e. , which is found to be unambiguously in the direction to reduce the NuTeV anomaly. A second consequence is the appearance of photon parton distributions of the proton and the neutron. In principle these can be measured at HERA via the deep inelastic scattering processes ; our predictions are in agreement with the present data.