content_image/343920.jpg content_image/343925.jpg
<img src='content_image/343920.jpg'>

## D. Reconstruction 

Reconstruction of the heavy lepton mass requires the identification of the SM lepton originating from the W decay. One possibility is immediately ruled out, since this lepton can only be one of the two leptons which have the same sign. We have calculated the transverse mass of the W for both of those leptons: 

<img src='content_image/343925.jpg'>

The distributions of m W T are shown in Fig. 4, for the correct and for the wrong lepton assignments. The combination that yields the lower value was designated as the W decay product. The correct lepton configuration was selected with this procedure at about 93% of the events. 

The two remaining opposite sign leptons, assumed to be produced directly by the heavy lepton-pair decays, were then assigned to the charged and neutral lepton decays according to their charges. Note that the above reconstruction procedure equally applies to events 

