Subject: Re: UED simulation
From: Pedro Mercadante <mercadan@fnal.gov>
Date: Thu, 20 Jul 2006 09:01:44 -0300
To: Greg Landsberg <landsberg@hep.brown.edu>
CC: 'Sergio Lietti' <lietti@fnal.gov>, "'Eduardo M. Gregores'" <gregores@fnal.gov>, 'Sergio Novaes' <novaes@fnal.gov>

Hi Greg,

Sorry for the long delay. I was preparing my Pythia code to have an output with just jets and leptons information so that I could read the events and apply cuts in a much more efficient way (I know that I could use ntuple but in this way I have more freedom.)

In the mean time I found a bug in the Pythia UED code. When I was trying to classify the events in e+e+, e-e-, mu+mu+ etc... I noticed that there is a factor of 10 more events with the minus sign!!! I trace back this error and it was due to the fact that the UED code is always decayng the excited state of the Z (Z1) in a lepton minus and the excited partner of the lepton (L1). Since the mass difference of Z1 and L1 is greater than L1 and gamakk the harder lepton mostly comes from the first decay.

I am working to fix it (but I need to dig in the Pythia code...). I am expecting that we are going to have less SS leptons after I fix it because events with two Z1 are almost always giving two hard SS leptons.

Pedro.