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Some clarification on how the main background is rejected

 WW / ZZ separation. Some clarification on how the main background is rejected how the detector performances are involved. ∆E J = 0.60  E J. ∆E J = 0.30  E J. Simulation with. Simulation with. Mass J3 J4 (GeV). Starting point. Mass J1 J2 (GeV). This presentation.

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Some clarification on how the main background is rejected

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  1. WW / ZZ separation Some clarification on how the main background is rejected how the detector performances are involved J.C. BRIENT

  2. ∆EJ = 0.60 EJ ∆EJ = 0.30 EJ Simulation with Simulation with Mass J3 J4 (GeV) Starting point Mass J1 J2 (GeV) This presentation Add background e± W∓ Effect when using the VDET btag Quantify the results with S/N ratio for different searches J.C. BRIENT

  3.  Select 4 jets Mass J3J4 (GeV) Simulation with ∆EJ = 0.30 EJ Mass J1J2 (GeV) Cross sections (fb) ZZ,WW,eWZ, J.C. BRIENT

  4. Processes 1 2 3 ZZ, WW, eWZ, With all decays to jets. In the fiducial volume of the detector, an isolated electron with high energy is a good tagging for process (3) ALL processes Process (3) Electron energy (GeV) J.C. BRIENT

  5. Reject if Electron Energy >100GeV (50 at low angle) MM2<500 and Electron Energy >5GeV MM2<250 and Electron Energy >2.5GeV The low angle coverage for electron is ESSENTIAL process e+ e− → e± W∓ Z (blue) almost disappears, while leaving processes (1) and (2) unchanged Mass J3 J4 (GeV) Mass J1 J2 (GeV) J.C. BRIENT

  6. ≈ 12.2 S(ZZ) B(WZ,WW) Select ≥ 2 b-jets Mass J3 J4 (GeV) Mass J1 J2 (GeV) J.C. BRIENT

  7. ≈ 100 ≈ 18.6 ≈ 2.4 S(WW,ZZ) B(WZ) S(WW) B(ZZ, WZ) S(ZZ) B(WW, WZ) WW region: Contains 89 % of the WW and ZZ region: Contains 71 % of the ZZ Select < 2 b-jets Before di-jet mass cut After cut J.C. BRIENT

  8. Other relevant backgrounds seem easier to remove (guess) i.e. WW, Z() could be rejected with missing energy and mass • e±W∓ background can be removed easily (with a good electron id. at low angle ) • the main problem is still the WW/ZZ separation • For ZZ rejection, a good VDET btag can help • the PFLOW performance is still the key point for the analysis J.C. BRIENT

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