The systematic uncertainty on the W mass and width measurement resulting from
the imperfect knowledge of electroweak radiative corrections is discussed. The
intrinsic uncertainty in the 4-f generator used by the DELPHI Collaboration is
studied following the guidelines of the authors of YFSWW, on which its
radiative corrections part is based. The full DELPHI simulation, reconstruction
and analysis chain is used for the uncertainty assessment. A comparison with
the other available 4-f calculation implementing DPA O(alpha) corrections,
RacoonWW, is also presented. The uncertainty on the W mass is found to be below
10 MeV for all the WW decay channels used in the measurement.Comment: 34 pages, 3 figure
