the two codes are identical, this large difference is essentially due to the different choices of shower variables made by the two PSMCs.

In fig. \[fig:pt\] we consider the transverse momentum distributions of the $W^+$ boson (left pane), and of the hardest jet of the event (right pane). These distributions are interesting since in the large-${p_{{\scriptscriptstyle}T}}$ region they are dominated by hard emissions, whereas in the small-${p_{{\scriptscriptstyle}T}}$ one there are logarithmically-enhanced terms that need be resummed (the pure NLO results diverge there). The comparisons among the three results for the two distributions follow the same pattern, as we expect. At small ${p_{{\scriptscriptstyle}T}}$’s, the shapes of  and of  are identical. To show this clearly, the latter results have been rescaled so as their first bins coincide with those resulting from . On the other hand, the  and  results are quite different in this ${p_{{\scriptscriptstyle}T}}$ region, owing to the different treatment of soft and collinear emissions by the two PSMCs. It is known that  tends to give softer spectra than , which is therefore what we expect to and do find with  and . At large ${p_{{\scriptscriptstyle}T}}$’s,  coincides with   – both in shape and in absolute normalization, which is again what we 