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NIKHEF group meeting


... group meeting. November 15, 2001. NIKHEF group meeting ... Online. NIKHEF group meeting. November 15, 2001. Freya Blekman, NIKHEF Amsterdam. My cuts up to now : ... – PowerPoint PPT presentation

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Title: NIKHEF group meeting

Current status of my analysisWeekly group
meetingNovember 15, 2001
T ttbar -gt 6J ins and outs
  • Problems
  • Too much background
  • S/B (qcd mainly) 1/3000 at least
  • (run I D0 ttbar-gt6j cross section paper)
  • Need some way to distinguish b jets
  • (CDF run I got S/B of 1/10 by using impact
    parameter b-tagging)
  • Purity most important (dont care much about

D0 Run I triggers and cuts
Online Offline
L1 4 trigger towers (ETgt5(7) GeV) 3 tiles (ETgt15 GeV) L2 5 jets 0.3 cone h lt 2.5 HT gt 110(115,120) GeV At least 5 jets 0.5 cone h lt 2.5 ET gt 8 GeV Ignore certain areas Soft muon tag Neural network Loads of MC and DATA for background
My cuts up to now
  • Online Trigger on ANYTHING
  • Offline Require 6 jets
  • (these are JCCA 0.5 runII cone jets)

What I did up to now (1)
  • Ran over p10.05.00 data
  • with Onnes filter framework (thanks!)
  • I think these were p10.4 recoed data (not sure)
  • Got NO ( events whatsoever
  • Went off to Belgium for the Erasmus school

What I did up to now (2)
  • Ran over P10.07 data
  • these were reconstructed with p10.07 too!
  • Got 10000 events (out of 3 million)
  • What was my lumi? Dont know. I started out with
  • Some of them actually had an impact parameter
  • Could not get run and event number from
    root-tuple (problems with Chaining, probably too
    many files)
  • Hot towers, no flat f
  • No fancy plots, sorry ?

P10.07 Real data, all 6 jet events This is part
of the sample (700 jets)
P10.07 Real data, all 6 jet events VERY high jet
multiplicity (NADA is NOT on)
And then there was light sorry I meant p10.09.00
  • No more root macros!
  • Luminosity monitoring available
  • Unfortunately, there was also
  • Shutdown SMT re-cabling
  • had to maintain the database, put in dead
    ladders, modified HV scheme.
  • more D0trigsim work
  • the certification of L3 filters is starting with
  • Its painful. Several crashes and bug fixes per
  • No time for looking at data

  • Run over all recent and decent data
  • I have the filters ready to do the following
  • Get all events with p10.07.00 5 JCCA jets out of
  • Select them more on the following cuts
  • 6 jets, all in h lt 2.5
  • HT of total event more than 150
  • (This will possibly become my particular trigger)
  • Check different permutations of jets and demand
    at least one Z.
  • Hopefully this will reduce my background to the
    level where I can look at single events and maybe
    see a real hadronic ttbar event

  • Actual look at new data
  • after Thanksgiving
  • (Hopefully)