SUSY DiLepton 2011

Liza Sneitzer

2 DiLepton SignaturesThree Analysis-> SS, OS, OS Flavor Subtraction.

a) χ ̃�0 →l± ν χ ̃�∓lsp

b) χ ̃�± →l± ν χ ̃�0lsp

c) χ ̃�0→l± l ∓χ ̃�0lsp

d) χ ̃�± →l± l∓ χ ̃�±lsp

Same Sign• Combination a and b decays, pair production of

same sign squarks or initial states involving gluino decays.

• Gluinos decay w/ equal probability into sparticle-antiparticle and particle-antisparticle

• Gluino model has small background.

OS• a, b, c and d• Very high background

OS Flavor Subtraction• Assuming lepton flavor conservation, c) and

d) produce 2 same flavor leptons. • All standard model 2 l backgrounds produce

OF and SF events at same rate. .

Signal Regions

Opposite-SignSR1) Emiss > 250 GeV TSR2) 3-jets (pT > 80, 40, 40 GeV),

Emiss > 220 GeV TSR3) 4-jets (pT > 100, 70, 70, 70 GeV),

Emiss > 100 GeV T

Same-SignSR1) Emiss > 100 GeV TSR2) 2-jets (pT > 50, 50 GeV), Emiss

> 80 GeV T

Flavour Subtraction SR1) Emiss > 80 GeV, Z-veto (80 < mll

< 100 GeV)SR2) Emiss > 80 GeV and at least 2

jets TSR3) Emiss > 250 GeV T

Analysis done over a grid that does searches with masses “frozen”

All Signal Regions Use Same Event Selection and Object Selection.

Event Pre-Selection

Events Removed If:• There is a “Loose Bad” jet. (Jet

cleaning) based on (emf, hecf,larq,hecq, sumpttrack, time, eta, pt, negE)

• If occupancy on electron or jet is bad, if electron or jet eta or phi point towards dead TX. (LAr Hole Veto)

• Primary Vertex>5 tracks• Cosmics Muon (z0 and d0 at PV)

Trigger

• For ee: EF_e20_medium• For mumu: EF_mu18• For emu:

– If e pt > 25: electron trigger– Else Muon trigger AND mu pt

>20

MC

• Pile up reweighting done as a function of mu to fit EF_mu18

• 2 leptons w/ mll>12GeV (meff from TLV, M_T)

• Signal Leptons tight and isolated

Event Selection

Electrons:• Robust Medium • pT > 20 GeV (25 GeV if leading)• |etacluster | < 2.47 • Removed if overlap with jets within

0.2<∆R <0.4 Signal Electrons: • Tight • pT_cone20/pT < 0.1 (track isolation)Overlap Removal: • If there is a jet within 0.2<∆R <0.4 electron

removed.

Muons:• Staco used (NOT muid)• pT > 10 GeV (20 GeV if leading), |η| < 2.4• |z0| < 1 mm, |d0| < 0.2 mm (cosmics)

Signal muons:• pT_cone20 < 1.8 GeVOverlap Removal:• ∆R < 0.4

Jets:• AntikT4Topo alg used.• pT >20GeV• |eta|<2.8Overlap Removal• ∆R < 0.2

MET:SimplifiedRefFinal

- MET from jets using EM scale and jet energy scale calibration - MET from electrons- Missing transverse energy from

isolated STACO muons - Missing transverse energy from

non–isolated STACO muons - MET not from electron or jet

cluster using the EM–scale

Object Definitions

Getting Started: Analysis Run on SUSY D3PD’s

SUSYTools• Package can be found at:https://twiki.cern.ch/twiki/bin/view/AtlasProtected/SUSYD3PDSnippets#SUSYTools• Download and Build Package either locally or

within lxplus or Athena.• Implement in your cutflow to for object

definitions, GRL’s, occupancy checks, and many more complicated tools.

• Runs over individual objects from an event:SUSYObjDef::IsElectron(int iEl, int RunNumber, float el_cl_eta, float el_cl_phi, float el_cl_E, float el_tracketa, float el_trackphi, int el_author, unsigned int el_isEM, unsigned int el_OQ, int el_nPixHits, int el_nSCTHits, bool isData, float etcut, float etacut, bool ischeckOQ, int value)• Can use SUSYTools dictionary w/ python,

NKRoot, RootFit, Athena, etc. (C++)

Within Package:• src-source files• SUSYTools-headers• Data-GRL’s• Macros-sample analysis• Cmt-configuration file

(contains requirement file)• README-tells you how to

build

Cutflow stream: egamma NEntries = 49793.958 MC Weight : 1.2463167>>>>>>>>>>>>>>> OS EE OSEE: 49794 : Total OSEE: 49794 : GRL OSEE: 49606.8 : El_LArgHole OSEE: 44873.1 : Jet_LArgHole OSEE: 4823.51 : Trig OSEE: 4823.51 : JetClean OSEE: 4817.37 : GoodVertex OSEE: 4817.37 : CrackVeto(NO) OSEE: 4797.78 : CosmicVeto OSEE: 341.23 : Exactly 2lepton+flavor OSEE: 281.057 : sign OSEE: 275.053 : mll OSEE: 173.155 : signal leptons OSEE: 118.021 : met>80 OSEE: 15.508 : SR-1 met>250 OSEE: 82.2693 : SR-2 3jets(80,40,40) OSEE: 7.83487 : met>220 OSEE: 12.8479 : SR-3 4jets(100,70,70,70) OSEE: 4.97172 : met>100

• Put together cutflow that matches SUSYDiLepton accepted cutflow.

• Cut flows on DiLepton workspace:https://espace.cern.ch/atlas-susy-etmiss/2leptonchannel/Lists/2%20lepton%20channel%20discussion%20board/AllItems.aspx

• Comparison cutflows on workspace: https://espace.cern.ch/atlas-susy-etmiss/2leptonchannel/default.aspx

Graphs in newest paper awaiting approval.