tth h bb cuts based analysis status progress n.
Download
Skip this Video
Download Presentation
tth, (h → bb): Cuts-Based analysis status/progress

Loading in 2 Seconds...

play fullscreen
1 / 13

tth, (h → bb): Cuts-Based analysis status/progress - PowerPoint PPT Presentation


  • 107 Views
  • Uploaded on

tth, (h → bb): Cuts-Based analysis status/progress. Chris Collins-Tooth 06-Feb-2007. Samples. Using Common Analysis, v00-01-05 (see TWiki) https://uimon.cern.ch/twiki/bin/view/Atlas/TthhbbAnalysis - ttH_rootples_Example_Analysis Signal tth(h → bb): 5340 (forced l + )

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'tth, (h → bb): Cuts-Based analysis status/progress' - jeslyn


Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
samples
Samples
  • Using Common Analysis, v00-01-05 (see TWiki)
    • https://uimon.cern.ch/twiki/bin/view/Atlas/TthhbbAnalysis - ttH_rootples_Example_Analysis
  • Signal tth(h→bb):
    • 5340 (forced l + )
    • 5341 (forced l - )
  • Backgrounds used:
    • 5855 AcerMC gg->ttbb (QCD)
    • 5214 AcerMC gg->ttbb (EW)
    • 5212 MC@NLO/Herwig ttjj (jj=bb removed).
cuts used see v00 01 05
Cuts Used (see v00-01-05)
  • Lepton:
    • e: Pt>25 GeV; EtCone<15 GeV;isEM 0x4FF; auth=1||3.
    • .mStaco: Pt>20 GeV; 2/dof<50 < ; EtCone40<50 GeV.
  • Jets: 6j; Pt>20 GeV; ||<5.
  • bJets: 4bj; bjetWeight 5.
  • Neutrino Solution: use colinear appx if no solution.
  • Sample 5212 (ttjj) only: remove if 4 unique bquarks
  • MWlep/had: 80.4  25 GeV.
  • Mt: 175  20 GeV.
  • Background + Combinatorics: Pt(J12+J22)>75 GeV (see later)......
signal and bg efficiencies
Signal and BG Efficiencies.
  • Latest “full sim” is Compared to Cammin [ATL-PHYS-2003-024]
    • Applied same cuts as Cammin and saved v00-01-05
    • On the whole encouraging.
  • Problem with ttjj
    • many events had >=4 unique b-quarks
    • Had to remove them, as ttjj(jj=bb)  ttbb
signal and bg efficiencies1
Signal and BG Efficiencies.

higher jet mult.

in MC@NLO?

  • Latest “full sim” is Compared to Cammin [ATL-PHYS-2003-024]
    • Applied same cuts as Cammin and saved v00-01-05
    • On the whole encouraging.
  • Problem with ttjj
    • many events had >=4 unique b-quarks
    • Had to remove them, as ttjj(jj=bb)  ttbb
signal and bg efficiencies2
Signal and BG Efficiencies.

higher jet mult.

in MC@NLO?

cut on 2 tops too harsh?

  • Latest “full sim” is Compared to Cammin [ATL-PHYS-2003-024]
    • Applied same cuts as Cammin and saved v00-01-05
    • On the whole encouraging.
  • Problem with ttjj
    • many events had >=4 unique b-quarks
    • Had to remove them, as ttjj(jj=bb)  ttbb
signal and bg efficiencies3
Signal and BG Efficiencies.

higher jet mult.

in MC@NLO?

25%

47%

cut on 2 tops too harsh?

15%

30%

17%

47%

  • Latest “full sim” is Compared to Cammin [ATL-PHYS-2003-024]
    • Applied same cuts as Cammin and saved v00-01-05
    • On the whole encouraging.
  • Problem with ttjj
    • many events had >=4 unique b-quarks
    • Had to remove them, as ttjj(jj=bb)  ttbb
slide8

Moving on.....

  • Look at signal and BG normalised to 30 fb-1
    • Problem: BG samples not big enough! Use AF?
    • No sensible distributions yet! – Can’t do shape analysis!
slide9

Optimisations/Cuts..

  • Lots of cut optimisations to consider; also new cuts like Pt(J12+J22)>75 GeV on bJets forming Higgs
    • I will add this cut to the CVS-based analysis
a cut pt j1 2 j2 2 70 gev on bjets forming h
A Cut: Pt(J12+J22)>70 GeV on bJets forming H
  • Red circles: signal (+ black dot = “correct” bjets).
  • Others: backgrounds

#5855 ttbb[QCD]

#5340 poslep

#5341 neglep

Pt J1

Pt J1

Pt J1

Pt J2

Pt J2

Pt J2

#5214 ttbb[EW]

#5212 ttjj

higgs bjets order by bjetweight
“Higgs bJets”: order by bjetWeight
  • Currently, analysis in CVS produces Higgs from highest Et bJets if >2 remain after t/tbar.
  • Tried using bjetWeight to order the jets if >2 “left over”.
  • No difference really, as most (~99%) of the selected events have only 2 bJets!
    • we have to improve how we reconstruct the tops to beat combinatorics!
common analysis things i don t like
Common Analysis: things I don’t like...
  • Removal of ttjj where jj=bb
    • Truly awful to devise algorithm to do this in tthhbbClass.cxx (!)
    • Settled on removing events with 4 or more UNIQUE TRUTH b-quarks in ttjj.
    • Typical Herwig b->bMeson->b: check mother, grandmother etc. to see if b is unique
    • We also see eg: b-g-g-g-g-g-bbar where ‘b’ is mother of ‘bbar’, and ‘b’ has no mother.
    • Output ntuple ‘improved-data’ has a new attribute to allow one to remove these events for ttjj: “my_truthUniqueBQuarks” (remove ttjj event if >=4).
    • doplots.C is a root macro in CVS and cuts out these events
  • runtth.sh makes 10 ntuples for samples 5212
    • the list of input files is too large for my shell (zsh)
    • these have to be merged manually into “5212All.root”
      • merge: TChain ch("improved-data");ch.Add("5212*.root");ch.Merge("5212All.root");
  • top-mass window seems too harsh.
  • jet calibration.. is it even done??
other things to implement
Other things to implement
  • Add soft muons(+n??) back to Jets.
  • Jet energy corrections based on v12.
  • See if there’s any way of improving combinatorics.
  • D=0, instead of colinear solution.
  • Improve Whad light jets (use 3+ jets?- Simon?).
  • S/BG discrimination with Neural Net (Helen).
  • Bill’s fitting code.
  • Others people would like to see / I have forgotten??
  • Volunteers?????
  • Not enough events for a BG shape analysis.