The Ntuples files are available on CASTOR storage. The can be found in the directory

{{{
/castor/cern.ch/user/d/dmaitre/BlackHatSerpaNtuples/PROCESS/ENERGY/
}}}

where there is a subdirector per part. One can have a list of the parts using (for example)
{{{
#!sh
rfdir /castor/cern.ch/user/d/dmaitre/BlackHatSherpaNtuples/Wm2j/7TeV/
}}}
and one would get 
{{{
born
loop
real
vsub
}}}