Measurement of top quark properties at D0
  We present a summary of the measurements of the top quark production and decay properties performed by the D0 experiment at the Fermilab Tevatron proton-antiproton collider at sqrt{s}=1.96 TeV using 1 fb-1 of data. We discuss the first simultaneous measurement of the ratio of branching fractions, R=B(t-> Wb)/B(t->Wq), with q being a d, s, or b quark, and the top quark pair production cross section, the first model-independent measurement of the helicity of W bosons produced in the top quark decays, and the first measurement of the integrated forward-backward charge asymmetry in the production of top quark pairs. 
E.Shabalina (for the D0 Collaboration)