<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <style type="text/css" style="display:none;"></style> </head> <body dir="ltr"> <div id="divtagdefaultwrapper" style="font-size:12pt; color:#000000; background-color:#FFFFFF; font-family:Calibri,Arial,Helvetica,sans-serif"> Hi all, I've been looking at using the current library of Rivet analyses for BSM limit setting, which is going to be an exercise involving some 'safety proofing' of the analyses! One of the issues we've run into is spurious signals arising from fake Z/Ws that shouldn't be faking. For example a model adding additional heavy flavour pair production, the lepton pairs from heavy flavour hadron decays have the possibility to fake Z/W signals (has a noticeable statistical effect in cases). The way around is then to build the Z from promptfs projection, which has the right effect from our PoV (I have some modified versions of Z/W analyses of interest I've been running like this, written by David Grellscheid) and would be happy to propagate a change like this through through other analyses needed and hand them over for testing. I think this is a sensible safety feature to add, and is already something experiments have attempted to cater for in the definition of the fiducial cross section, via track-primary vertex association or something along those lines, so should be mirrored in the rivet routine. The question then is should there be a switch in the convenience Z/WFinders checking for isPrompt on the leptons by default? I think this would then be sensible for people going forward, as it would be sort of in the spirit of the Finders, doing the hard work for you and all that, and making the sensible choices needed by default. Obviously in quite a few cases the Finders aren’t even used, so sorting the projections out would still be done by hand. Anyway wanted to see if there are any opinions on this before I start churning through old analyses or anything like that. Cheers, David </div> </body> </html>