W3

• Target plots for week 3 for Ztoee, Ztotautau, Ztomumu
  • The number of leptons, taus, electrons, muons, jets (already there)
  • PtCone20, PtCone30, PtCone40 for leptons, electrons, muons (done - not done taus because no value there)
  • The pT distribution for leptons, electrons, muons, taus, jets (done)
  • The Eta distribution for the above (done)
  • dR between objects (lepton and jets for ex)
• Can we deduce the reconstruction efficiency for individual e, mu, tau based on the distributions we have?

W4

• First find out whether 'leptons' vector includes only electrons or muons, or taus too - confirmed as just electrons and muons.
• Investigate ΔR at small values where there is a big peak around zero to see where to make cut. Look at the following values of ΔR:
  • between lepton 0 and nearest tau
  • between electron 0 and nearest tau
  • between tau 0 and nearest lepton
  • between tau 0 and nearest electron
  • between tau 0 and nearest jet
  • between jet 0 and nearest tau
• Make cuts to only class each particle as one type with the following order of preference
  • Muons
  • Electrons
  • Taus
  • Jets
• (i.e. an electron will only be included if it is not in the same place as a muon; a tau will only be included if it is not in the same place as a muon or an electron; etc.)
• Remake all plots, including sub-leading leptons and paying more care to graph limits, bin sizes (particularly using half-integer bins for integer quantities)
• Look at truth level objects:
  • Consider, for example, ΔR between truth muon and reco muon in Z to mumu
  • Look at reconstruction efficiency as function of other properties (such as eta)

W5

• Remove pT cuts in PhysicsProjectMPhys.py (done)
• Look at ΔR between:
  • Reco tau (0,1,2,3) and closest truth electron
  • Reco tau (0,1,2,3) and closest truth muon
  • Reco tau (0,1,2,3) and closest truth tau
  • (All done)
• Try removing taus with passEleOLR and then plotting ΔR again - is there any improvement?

W6

-Code

• Try to fix double-counting of truth taus
  • Done by only including taus with status = 2 and barcode < 10000
  • These properties were identified by looking manually at truth particle printout data
• Separate taus into matched and non-matched (done)
• Plot various things with matched and non-matched taus stacked
  • BDTJetLoose, Medium, Tight - Jihyun
  • Number of tracks - Robin
  • pT, eta, etc.

-Analysis

• The ratio of efficiency cut to background cut
• Puzzle: BDTMediumJet = 1 in Z->tau tau showed no rectau matched with truth tau, dR>1 why?

W7

• Look at truth taus in ttbar
  • Why are there maybe twice as many as there should be?
  • Look at how many come from b quarks - either by looking at parents or by ΔR matching
• Combinations of jet BDT cuts and NTrack cuts
  • In both Z to tau tau and (more importantly) ttbar:
  • Every combination of No jet BDT cut, loose, medium, tight with and without NTrack cut in a table
  • and replicate Week 6, Fig 4, "Number of tracks" after loose, medium tight BDT jet cut
• Few other points (consider later)
  • In Z to tau tau events, after removing duplicated truth taus, there are still, even though very few, "some" 3 truth taus. (as shown in W6, Fig. 1)
  • Mphys_vars.(py? file?): Add variables regarding ttbar
  • For 3 tracks in tau, it is possible that there is only 1 charged pion but with 2 charged electrons, produced by photons along with neutral pions. Are there any ways that we can distinguish this event from the actual 3 charged pion tracks?(with Rustem)

- Thursday

• Try to remove pT cuts
• Plot truth lepton pT distributions
• DR between fake/real taus and truth b quarks
• Matching between reco taus and reco b jets?

W8

• To tackle actual b-jets being misidentified as taus:
  • Plot DR between each reco tau and nearest real b-jet
  • Tighten tau selection (jet BDT) and plot again
  • 4 plots in total: no BDT cut, loose, medium, tight
• To tackle actual taus being misidentified as b-jets:
  • Plot DR between each reco jet and nearest truth tau
  • Tighten jet selection (cut on BTagMV2c00/10/20) and plot again
  • Maybe 4 plots in total? (no cut, then eg BTagMV2c00 > 0.75, BTagMV2c10 > 0.7, BTagMV2c20 > 0.7)
• To see what difference these cuts make
  • Plot DR between each reco tau and nearest reco jet
  • 16 plots in total: each combination of tau cut and jet cut

- Thursday:

• Re-plot Fig 1 with a log scale to better identify a good place to cut
• Plot DR between truth taus and truth b-jets to see how many genuine taus we are getting from a b-decay (and thus how many come from a W decay)
• Related to this - maybe look at parents of truth taus. When parent is W, see how often this overlaps with a truth b.
• Look at reco taus that overlap with reco b-jets. Plot 2D hist of whether tau is real and whether b-jet is real. Do this for all combinations of tau cut and jet cut (except no jet cut)

W9

- Tuesday:

• Re-plot Fig 1 with a different min-y so we can see everything
• Find out the recommended cut values of BTagMV2c...
  https://twiki.cern.ch/twiki/bin/view/AtlasProtected/BTaggingBenchmarks#b_tagging_Benchmarks_for_tagger
• Plot 2a (DR between truth taus and real jets) for 3 different categories depending on truth tau parent: no parent, b hadron, W boson
• Extend 2D hists to 4x4 to include all reco jets in 4 categories (combinations of tau ID and b ID)

- Thursday:

• Re-plot Fig 3b (DR between truth taus with W as parent and nearest real B jets) with smaller bin widths to see what happens around zero
• Re-plot Fig 4c (4x4) only considering truth taus that have W as parent
• Do the same for electrons and muons, only considering those that have W as parent OR have tau as parent that itself has W as parent
• Look at truth flavour of particles that are reconstructed as taus but aren't truth taus or truth Bs (this is the 1518 in Fig 4c)
• Look at properties of real and fake taus, where the reco tau passes tight tau cut and the truth tau has W as parent

W10

- Tuesday:

• Look at fake taus: how many overlap with truth electrons and truth muons (that come from W) ? if they don't, then what is the truth jet flavour? Plot Fig. 3 again - hopefully now including electrons and muons
• Re-plot Fig 4 with log y - make sure we don't lose things off the bottom of the plots
• Sort out logic behind Fig 2 (4x4) plots so that they only consider reco (tau, e, mu) not jets that overlap with these
• Plot Fig 1 (DR between truth taus to nearest real b jets) for truth elecs and truth muons to see if there is a larger overlap (which would suggest overlap is due to B decay) or the same overlap (which would suggest it's due to spin stuff)
• Look at parents of W which are parents of tau again - is there anything special about the W when the tau overlaps with a real b jet?

- Thursday:

• Manually remove reco taus that overlap with reco electrons or muons.
• Then re-plot figs:
  • 1a
  • 2a
  • all of 5 - separate lines for different types of background (e, mu, jets)
• Plot DR between truth lepton and nearest truth b quark for each flavour of lepton

• (additional thing if we finish: replot 1b and 1c for different levels of electron/muon ID)

W11 Tuesday

- What we discussed:

• We are already using loosest possible electron selection (anything reconstructed as electron) for vetoing tau candidates
• The problem of muons reconstructed as taus can be ignored for now as it is small relative to other backgrounds
• Electrons reconstructed as taus are mostly from Ws - this is a problem. Hopefully tighter tau cut can reduce this.
• Total charge of tracks for reco taus could in principle be anywhere in range -3 to +3, although may already be selected to be +/- 1
• Why are there so many more entries in DR between truth taus and nearest truth b quark than for truth electrons and truth muons? Could be a mistake in code

- What we plan to do:

• Double check code for DR between truth taus and nearest truth b quark. If it seems correct, try to find what is going on. Could be to do with incomplete truth b quark data.
• Remake total charge of tracks plot with range -3 to +3
• Select events with 2 b-jets (tight ID), 1 tau (tight ID), and 1 electron or muon. (we will start by requiring at least these numbers, as we are not yet requiring any particular conditions on electrons or muons). Re-plot the 2D histogram and fake tau flavour to see how it has improved/changed
• When we receive Ntuples with new tau ID variable: plot this variable for the matched taus and different backgrounds

W11 Thursday

- What we discussed:

• DR between truth electrons/muons and nearest truth b - plots still don't look right. Why 70,000 entries and there appears to be overlap at 0? Looks like a mistake.
• Appears that there is already a selection on taus requiring total charge of tracks = +/- 1
• By requiring 2 b jets we have reduced the b background in taus, elecs and muons to the extent that it is now less of a concern than light jets and electrons faking taus (this in particular is still high and we're not sure why?)
• Fake electrons and muons from other sources are high.
• Why so many muons? Could possibly be a bug in code, or due to low pT muons from pion decay in detector
• A few events with 3 b jets. Could be other flavours but this is relatively unlikely with the tight b-jet ID, could be genuine b jets from ttbb events
• Not many events with 2 taus or 2 electrons
• Properties of real/fake taus haven't really changed with event selection
• BDTJetScore - we will be able to decrease background by cutting tighter on this, although we will also lose signal

- What we plan to do:

• Check DR between truth electrons/muons and nearest truth b - hopefully this is a bug and we can get more consistent numbers
• Check if there is a tau track charge cut in python file that we didn't spot
• Plot BDTJetScore for all reco taus, not just those passing tight ID
• Check if there is a bug in muon selection
• For each of the following cuts, reproduce: all 3 2D histograms, fake tau flavour, number of each object (don't need combined lepton no)
  • Tighter tau ID (maybe 0.8)
  • Tau pT > 25 GeV
  • Medium muon ID
  • Tight muon ID
  • Muon pT > 20 GeV
  • Medium electron ID
  • Tight electron ID
  • Electron pT > 20 GeV
  • Also do these with no new cuts because it seems like the new NTuples are slightly different (dramatically different in the case of the muons)
• (do all these in python file so that they are all produced simultaneously - may need more events eg 5 or 10 million)
• Check the proportions and number of reconstructed taus, fake taus, real taus after such cuts.
• Homework: Find the momentum of pion that it is likely to escape the detector, given that the pion lifetime is of order 26 nanosecond and the length of the detector is ~2m.

W12 Tuesday

- What we discussed:

• We're not sure exactly how the tight tau cut works. Might have some pT dependence. We should try to check the documentation.
• The BDTJetScore plot after event selection (caption is wrong - requires 1 tau not 2) is a sum of 2 distributions: for the tight tau required for selection, and for the (usually non-tight) taus that also happen to be in the event.
• Electron/muon pT and ID cuts look good. We should use tight ID, and for pT we might have to go higher than 20 GeV.
• Plots for tau pT cut are identical to no cut (this is just a mistake)

- What we plan to do:

• Remake plots for tau pT cut
• Look at tau documentation - try to find how tight tau ID works
• Find a way to use separate uncut electrons and muons for purpose of vetoing taus
• Check that removing electron/tau overlap is working
• For electrons and muons, use tight ID and Pt > 20 GeV as a starting point for the following:
• Plot PtCone (var) divided by Pt and also EtCone (topo) divided by Pt for electrons, muons, taus to see if this discriminates well between signal and background
• Plot the signal/background ratio of the integral of Pt as a function of Pt cut

W12 Thursday

- Brief summary:

• Change OLR to use loose ID and 10 GeV pT for both electrons and muons (currently there are no cuts on those used for OLR)
• Would be good to use full samples (we think 20 million)
• Fix pT distributions
• Only plot pT ratios up to 50 GeV
• Also plot BDTJetScore in same way

S2 W1 Tuesday

- Decide on second round of baseline cuts:

• Electrons:
  • Pt > 25 GeV
  • PtVarCone40/Pt < 0.3
• Muons:
  • Pt > 25 GeV
  • PtVarCone40/Pt < 0.3
• Taus:
  • Pt > 30 GeV
  • BDTJetScore > 0.9

S2 W2 Tuesday

• pTCone/pT < 0.3 is very loose. We will try changing this to 0.1
• Plot ETCone for electrons and muons on top of ptCone cut
• For plotting electron and muon properties, try removing tau event requirements to increase better statistics so we can see the shapes of distributions more easily
• Look at D0 and Z0 variables, and also D0/sigma_D0 and Z0*sin(theta)
• Lower priority: look at nearby objects to taus. Plot distance to closest electron, muon, (non b-) jet for real taus and fake taus.

S2 W2 Thursday

• Try plotting signal efficiency vs background efficiency for:
  • d0, d0sig, z0
  • EtTopoCone/pT 20/30/40
  • tau DR

S2 W3 Tuesday

• Choose a point to cut on D0Sig for electrons and muons
• Run with all cuts including this one to see what current signal and background numbers are
• Then disable one cut at a time to plot:
  • the distribution
  • signal eff vs background eff
  • S/sqrt(S+B) as a function of the cut
• for:
• Electrons:
  • pT - J
  • ID - R
  • pTCone - J
  • ETCone - J
  • D0, D0Sig, Z0 - R (remember to get D0 and Z0 from the all-cuts-enabled root file, but D0Sig from the NoElecD0SigCut file)
• Muons:
  • pT - J
  • ID - R
  • pTCone - J
  • ETCone -J
  • D0, D0Sig, Z0 - R (see above comment)
• Taus:
  • pT - J
  • BDTJetScore - R

S2 W3 Thursday

• Plot BDTJetScore from zero for:
  • Tight taus
  • Medium taus (that are not also tight taus)
• Do efficiency plots not using 2D hist and include:
  • Line of futility
  • Marker of where current baseline cuts are
• FakeElecFlavour

S2 W4 Thursday

Robin:

• Plot children of fake electrons that are truth taus from W - done
• pT distribution (up to maybe 100-200 GeV) of real electrons vs fake electrons that are truth taus from W - done
• Fake muon flavour - done
• Plot children of fake muons that are truth taus from W - done
• Plot parents of fake muons that are truth muons (but aren't from W) - done
• pT distribution (up to maybe 100-200 GeV) of real muons (reco muons that are truth muons from W) vs reco muons that are truth muons from truth taus from W - done

Jihyun:

• Reclassify fake electrons/muons that are truth taus from W as real electrons/muons - do this in PrepTopEvent by changing definition of TruthMatchW
• Re-plot the following properties with the current baseline cuts, and signal vs bg efficiency and S/B:
  • pT
  • pTCone, ETCone
  • d0, d0Sig, z0sin
  • any more? ID?

S2 W5 Tuesday

• Remake Fig. 4-7 with all cuts and event selection disabled - Robin
• Change BDTJetScore cut back to 0.9 before the following: - done
• Add number in brackets in table 1 which is number of fake taus that are leptonic truth taus - Jihyun
• From sections 7 and 8 choose different set of electron (Robin) and muon (Jihyun) cuts
• Add lines in plots to indicate current cut point

Agreed cuts:

• Electrons:
  • d0Sig: 2.5 (no change)
  • ID: tight
  • pT: 20 GeV
  • ETCone30/pT: 0.14
  • pTCone20/pT: 0.14
• Muons:
  • d0Sig: 2.5 (no change)
  • ID: tight
  • pT: 20 GeV
  • ETCone30/pT: 0.1
  • pTCone20/pT: 0.18

S2 W6 Tuesday

• pT and eta distributions for leading 2 jets in fake tau events and real tau events (hopefully fake tau event jets will have large pT and small eta)
• Invariant mass of:
  • leading 2 jets
  • leading jet + tau
  • 2nd jet + tau
• ... for fake tau events and real tau events. Hopefully for fake taus will see some sort of peak at W mass
• If these have been successful then can make some jet cuts and re-plot missing pT and maybe number of jets again
• and (later) for those which reconstruct close to W mass we could plot invariant mass of these plus b-jet to see if it gives top mass

• Look at possible background MCs of events with a single W to lepton plus bbar?

S2 W6 Thursday

• Plot JVT for jets 1 and 2 in fake and real tau events
• Plot transverse mass of electron-neutrino system and muon-neutrino system (should partially reconstruct W mass)
• Plot transverse mass of each of the above systems combined with each b-jet (should partially reconstruct top mass)

Extra W6-7

• Remake W6Tues Fig 2&3 putting events in 0 bin when there is no appropriate jet. Then fix the S/B plot. - J
• Remake Fig 8 using jet overlapping with tau rather than tau itself. - R
• Remake Fig 11 using nearest b-jet. - R
• Change electron/muon pT cut in python - J
• Look at events with 1 tau and see how many have a 2nd (meeting the cuts Rustem mentioned in email) - J
• Write a list of proposed overlap removal - R

• Look at the effect of cutting on InvMassTauJet1BJet1 ON TOP OF a cut on InvMassTauJet1 - R

W7

• Apply jet cuts from Rustem's email
• https://svnweb.cern.ch/trac/manc/browser/PhysicsNtuple/PhysicsLight/trunk/python/PhysicsLightRun2ttHObjs.py#L102
• Always consider events with 0 jets (after these jet cuts) when calculating S/B
• Transverse mass of (lep plus missing) for real tau events plus fake tau events
• Re-make invariant mass plots after these new jet cuts
• Plot DR between elec-elec, mu-mu, tau-tau
• Plot difference between tau pT and tau-jet pT, both this quantity and it divided by tau pT

W8

• Apply event cut to exclude all events where (jet1 passes jet cuts AND m(tau, jet 1) between 55-100 GeV)

• Implement final event/object selection in CERN python. Make sure to include:
  • Event selection (1 lep, 1 tau, 2 b-jets using same variables as Manchester code, plus the invariant mass veto)
  • Object selection (elec, mu, tau, plus loose elec/mu)
  • Overlap removal

• At Manchester:
  • Make candidate with exactly 1 tight e/mu and at least 2 tight b-jets
  • Call CandEvent.getReco to access all objects in event without selection
  • Find e/mu away from the primary e/mu
    • Make plot for number of these found
    • and another for how many are close to one of the b-jets

W8 Thurs

• Remake all of the distributions of the cut variables, having applied all other cuts, but now incorporating the full statistics of all available MC samples.
• This involves:
  • DONE - Re-enable plotRecoLep in CERN code to show subfolders for real electrons, fake electrons etc.
  • DONE - Add functionality in CERN code to disable one cut at a time
  • DONE - Check histogram dimensions are correct
  • DONE - Check this is working by running CERN code at Manchester
  • DONE - Commit to SVN and update at CERN
  • IN PROGRESS - Run at CERN for small number (1000) to check that disabling cuts works
  • Run at CERN for full statistics (>= 20m)
  • While running, write a python script to make the combined histograms when finished

• Make a first data-MC comparison. The first “control” I’d suggest would be to select events with exactly one tight electron and exactly one tight muon and two b-jets. this is the “classic” ttbar -> dilepton signal and should be totally dominated by ttbar. (Include in the plots the equivalent of fig 1).
• This involves:
  • Add new event selection for exactly one tight elec and exactly one tight muon and 2 b-jets
  • Make basic event-level plots like elec0 pT, mu0 pT
  • Test using CERN code at Manchester. Commit to SVN and update at CERN
  • Run at CERN for 20m
  • Make stack plots

W10 Tues

• Try to match data preselection. Put it before other event cuts
• Include other MCs and try to separate out ttbar into signal and background
  • possible idea for how to do this: make event selection that selects events where one of the object used to select the event is a fake. then at the end, go in this directory in TBrowser and manually copy out the values from CutCand into the table
• Remake plots
• (Already done) plot number of additional taus in both 1elecExact_1muonExact_2bjet and 1lep_1tau_2bjet
• Plot number of additional leptons (including taus) in 1lep_1tau_2bjet event selection
• Plot same sign/opposite sign for elec_muon

To do

• Understand sources of truth taus in Ztoee, Ztomumu samples (low-ish priority)
• and also events with 3 truth taus in Z to tau tau