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SUSY: RpV with ’. di-electrons events

SUSY: RpV with ’. di-electrons events. Auguste BESSON (ISN-Grenoble) SUSY framework, signal and topology Background and expected results First look at the data : 2 - electrons selections, what can we see ? Conclusion. SUSY framework.

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SUSY: RpV with ’. di-electrons events

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  1. SUSY: RpV with ’. di-electrons events Auguste BESSON(ISN-Grenoble) • SUSY framework, signal and topology • Background and expected results • First look at the data : 2 - electrons selections, what can we see ? • Conclusion. New Phenomena, December 14th 2001.

  2. SUSY framework • mSUGRA model : m0 , m1/2 , A0 , tan  , Sign  • R-parity violated : • Double production in Rp conservated • Decay of LSP via RpV. • One dominant coupling : L : left-handed lepton doublet Q : Quark doublet D : anti-quark singlet New Phenomena, December 14th 2001.

  3. Signal topology with ’122 • Vertex : • LSP decay with : • ’ can be small Without decreasing the signal. New Phenomena, December 14th 2001.

  4. Signal topology (2) • Final state. 2 LSP decay : • 2 like sign leptons with high pT + 4 jets + small missing Et. • Branching ratios of LSP  charged lepton : • depends strongly on Sign  . ( and m0 , m1/2, tan  ) • Example : Br.ratio very small for  > 0 . • some regions of the parameters space will be difficult to reach. New Phenomena, December 14th 2001.

  5. Background • 2 like sign electrons + 4 jets + small missing Et. • t-tbar :  6.5 pb • Z ee : • 20 < pT < 60 : 139 pb • 60 < pT < 120 : 165 pb • 120 < pT : 1.9 pb • Z  : • 20 < pT < 60 : 137 pb • 60 < pT < 120 : 164 pb • 120 < pT : 1.9 pb • WW/ZZ/ZW  leptons : 7 pb, 0.9 pb, 2 pb • W/Z + jets. • QCD with pT > 10. + e fake :  600 pb • Misidentification probability of the sign of the electrons ? • e fake probability ?  10-4 Need further studies. New Phenomena, December 14th 2001.

  6. Very preliminary study with SHW/PGS • SCAN in the SUGRA parameters space. • m0 : 50 to 500 step of 50. • m1/2 : 80 to 220 step of 10. • A0 : 0 • Tan  : 5 • Sign  : +1, -1. • 1000 events per point. New Phenomena, December 14th 2001.

  7. Trigger and events selection • Very simple selection: • 2 like sign electrons • pT > 10 GeV ;  < 1.0 • Jets : • pT > 10 GeV ;  < 2.0 • Invariant mass of e-e : not between 80 and 100 GeV. New Phenomena, December 14th 2001.

  8. Cross-sections m 0 m 0 m1/2 m1/2 New Phenomena, December 14th 2001.

  9. Efficiencies Very low efficiency (branching ratios of LSPelectrons small) m1/2 m1/2 m 0 m 0 New Phenomena, December 14th 2001.

  10. Efficiencies (2) • 20k to 50k events for each background. • No Bkgd events survived to the like sign leptons cuts. • The most difficult to estimate is QCD + efake backgd. • Very rough estimate of efficiences but promising results. New Phenomena, December 14th 2001.

  11. Exclusion contours • Very preliminary : • L = 200 pb-1 • 90% Conf. level. • Bakgd studies is only beginning. •  > 0 difficult to exclude. New Phenomena, December 14th 2001.

  12. Run I Exclusion contour for Sign  < 0 and tan  = 2 and 6. PRL 83, 4476 (1999) New Phenomena, December 14th 2001.

  13. Selection of 2 high pT leptons Data ( < Discussions Saclay-Grenoble) • Physics : Susy RpV final state in 2 leptons + X • Wich selection for 2 elec ? tried with p10.07.01, ~ 5 416 000 Evts, ~ 940 Runs. • Is it reasonnable ? yes if ~ 1% data New Phenomena, December 14th 2001.

  14. 2 electrons selection • P10.07.01, ~ 5 416 000 Evts, ~ 940 Runs. • Selections 2 electrons: • + “loose” cuts : • HMx41 < 700 && E > 5 • -0.2 < iso < 0.2 • 0.85 < Emfrac < 1.1 • 0.05 < Emfrac layer 1 < 1.0 • 0.05 < Emfrac layer 2 < 1.0 • 0.10 < Emfrac layer 3 < 0.8 • 0.01 < Emfrac layer 4 < 1.0 2 EMPART_S objets 454 465 events with 1 electron candidate i.e. ~ 8.4 % 20 073 events with >=2 electron candidates i.e. ~ 0.37 % New Phenomena, December 14th 2001.

  15. 2 electrons selection 2 EMPART_Z objets • P10.07.01, ~ 5 416 000 Evts, ~ 940 Runs. • Selections 2 electrons: + “loose” cuts. • + Eelectron > 10 GeV. • Tests on Monte-Carlo QCD pT > 2 GeV (p10.07), same cuts : 0 / 200 670 evts. (cellNN) 501 080 events with 1 electron candidate ~ 9.3 % 120 205 events with >=2 electron candidates ~ 2.2 % (thanks to Pavel Demine.) New Phenomena, December 14th 2001.

  16. Remarks • Hot cells : nNada = 0. • Hot towers : Not cut • Other selections raw data : sel. 2 electrons of the W/Z group • Emreco cuts • 5 < pT < 200 • EMfr != 1.0 • iso != 0.0 ~ 2% of the evts. Can be used Why ? New Phenomena, December 14th 2001.

  17. what about Z  ee ? (CellNN) Tight cuts: HMx41 < 150 pT > 15  < 3 -0.05 < iso < 0.2 0.9 < Emfrac < 1.1 0.05 < Emfrac layer 1 < 1.0 0.05 < Emfrac layer 2 < 0.6 0.25 < Emfrac layer 3 < 0.8 0.001 < Emfrac layer 4 < 0.5 nNADA = 0 pT1/pT2 < 3. flrS1 < 30. flrS2 < 50. 2.5 <| 1 - 2 | < 3.6 2.0 <| 1 - 2 | < 4.0 Auguste Besson

  18. Hot towers : not cut • Eta / phi. (all EMPART objects) New Phenomena, December 14th 2001.

  19. Emfrac(S_EM block)of all Em candidates • Why do we have some candidates with Emfrac < 0.8 in this block ? Auguste Besson

  20. What about jets ? (JCCA block) • Same 2e selection + selection of jets • Phi vs. Eta • quality Cuts: 0.05 < JCCAEMF < 0.95 JCCACHF < 0.4 JCCAHotF < 10. JCCAn90 > 1 JCCAE > 8. New Phenomena, 14th 2001.

  21. Selection 2 el + 4 jets • Same 2e selection : HMx41 < 150 pT > 15  < 3 -0.05 < iso < 0.2 0.9 < Emfrac < 1.1 0.05 < Emfrac layer 1 < 1.0 0.05 < Emfrac layer 2 < 0.6 0.25 < Emfrac layer 3 < 0.8 0.001 < Emfrac layer 4 < 0.5 nNADA = 0 • 20 073 2 events with 2 el candidates : • 115 events left with the 2 el cuts • 64 events left with at least 2 jets • 2 events left with 4 jets. • selection of at least 4 jets: 0.05 < JCCAEMF < 0.95 JCCACHF < 0.4 JCCAHotF < 10. JCCAn90 > 1 JCCAE > 8. pT > 10. JCCAdEta < 0.8 or JCCAdEta > 1.2

  22. Display

  23. Conclusion • Thanks to like sign dilepton cut : Exclusion contours should be improved significantly even with 100 or 200 pb-1. • For more confident results : Full reconstruction and/or PMCS. • Use W/Z group selection for the raw data. • Quality cuts for electrons/jets need to be optimized. New Phenomena, December 14th 2001.

  24. Feynman diagrams New Phenomena, December 14th 2001.

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