Hard gluon radiation and the top mass value from CDF

The effect of hard gluon radiation on the top quark mass determination at Tevatron energies is studied. An expectation value 〈 Δm 〉 for the correction implied on mtop is defined, and it is shown that the hard gluon effect is of the order of GeV. Quantitative numerical results are obtained on the basis of the complete higher order matrix elements for production and decay of the top quark.