Parton distributions incorporating QED contributions
Institute for Particle Physics Phenomenology, University of Durham, DH1 3LE, UK
2 Rutherford Appleton Laboratory, OX11 0QX, Chilton, Didcot, Oxon, UK
3 Cavendish Laboratory, University of Cambridge, Madingley Road, CB3 0HE, Cambridge, UK
* e-mail: email@example.com
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.
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