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Radion searches in CMS

Radion searches in CMS. A first look to f hh G. Dewhirst, L. Fano, S. Gennai , S. Nikitenko. s Br of radion depends on m f , m h , L f (scale), x ( f -h) mixing. t jet. l. p. p. b. b. f hh tt bb t +l+bb+ n. This final state is common also to

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Radion searches in CMS

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  1. Radion searches in CMS A first look to fhh G. Dewhirst, L. Fano, S. Gennai, S. Nikitenko Simone Gennai SNS, INFN-Pisa

  2. s Br of radion depends on mf, mh, Lf (scale), x (f-h) mixing Simone Gennai SNS, INFN-Pisa

  3. Simone Gennai SNS, INFN-Pisa

  4. Simone Gennai SNS, INFN-Pisa

  5. Simone Gennai SNS, INFN-Pisa

  6. tjet l p p b b fhhtt bbt+l+bb+n This final state is common also to other scenarios, like MSSM or little Higgs, in the ED case the cross sections are enanched for some model parameters. (MF=300 GeV, Mh=125 GeV) Possible backgrounds: tt, W+jj, Z+jj Simone Gennai SNS, INFN-Pisa

  7. Few words about tt bkg • tt is the most dangerous • Atlas has considered: • ttWWbb l+n+jj+bb, sxBR=180 pb • Probably we should consider also: • ttWW+bb l+n+t+bb l+n+tjet+bb, sxBR=18 pb • considering the t-tagging efficiency and bkg rejection this channel could also contribute. Simone Gennai SNS, INFN-Pisa

  8. Trigger and basic selections • e/m + t-jet trigger will be used • At least 3 jets + 1 e/m to be reconstructed • t-jet identification (HLT + off line) • At least 1 jet b-tagged (off line) • ET missing based selection (to suppress W+jj) • Invariant mass of bb and t+lepton • Invariant mass ot 2 reconstructed Higgs Simone Gennai SNS, INFN-Pisa

  9. Where to find Real tau: • When electron is collinear to 1st L1 Tau: • 30% Real Tau is the 2nd Tau jet • 38% Real Tau is the 1st Central jet • 20% Real Tau is the 2nd Central jet • 8% Real Tau is the 3rd Central jet • ..... • Tau Tagging efficiency = 35% • limiting to first 3 highest energy jets: Eff. = 30% Tau isolation parameters: PtLT>10 GeV RM=0.1 RSIG=0.07 RISO=0.4 1.OR.3 Tracks inside Signal cone. Simone Gennai SNS, INFN-Pisa

  10. B tagging Efficiency • Tagging efficiency : # of events with tagged jet / # matched events • Total Efficiency : Eff. Match X Eff. Tagging • Btagging = Tk>2, sip >2 • As efficiency for 1st and 2nd Jet are different, we can relax selection but requiring 2 tagged jets instead of at least 1. B-jet Simone Gennai SNS, INFN-Pisa

  11. Signal invariant mass distributions FAST Vs FULL No big discrepancy between full and fast simulation for the signal! Simone Gennai SNS, INFN-Pisa

  12. Signal PT distributions FAST Vs FULL Simone Gennai SNS, INFN-Pisa

  13. Preliminary results Efficiency parametrization has been performed in order to have the same number of signal events in both Full and Fast simulation Ev. tt = 107 Ev. W+jj = 0 Ev. Z+jj = 33 Ev. Bkg = 140 Ev Sig = 43 S/sqrt(B+S) = 3.2 Simone Gennai SNS, INFN-Pisa

  14. 3-5 Sigma regions Really PRELIMINARY CMS, 30 fb-1 fhhggbb fhh tt bb Lf (GeV) Mf=300 GeV Mh=125 GeV 3 sigma 5 sigma Theoretically excluded Theoretically excluded x Simone Gennai SNS, INFN-Pisa

  15. -> hh -> bbbb – First View same point: mf = 300 GeV, mh = 125 GeV (*) at least one parton in the final state Simone Gennai SNS, INFN-Pisa

  16. Selection Efficiency - Energetic Threshold 4 Jet ET > 50 GeV : 10% signal 1% QCD (PT>100 GeV) Signal Eff 1 Jet 2 Jet 3 Jet 4 Jet Jet ET 4b QCD – no cut 4b QCD – PT > 100 GeV Eff Eff Simone Gennai SNS, INFN-Pisa Jet ET Jet ET

  17. Selection Efficiency Energetic threshold + btag 1 leading Jet 2 leading tagged Jet 3 leading and next-to-leading tagged Jets Signal Eff b-tag: 2 tracks with Sip2D>1.5 Jet ET 4b QCD – PT > 100 GeV 4b QCD – no cut Eff Eff Simone Gennai SNS, INFN-Pisa Jet ET Jet ET

  18. Signal Kinematics <b jet> = 2.5 <jet> = 4.6 Eta and PT distribution - 4 leading Jets Eta PT Simone Gennai SNS, INFN-Pisa

  19. Signal Reconstruction Best jets combination is chosen minimizing the difference between all possible reconstructed mass M(i,j) – M(k,l) Mbb  124  39 GeV Jets are preselected in the barrel requiring ET>35 GeV Mbbbb  304  64 GeV Simone Gennai SNS, INFN-Pisa

  20. Cuts and Selection Criteria 1 Jet ET > 177 GeV OR 3 Jets ET > 86 GeV OR 4 Jets ET > 70 GeV AND Invariant reconstructed mass: 124 - 1.5s < Mbb < 124 + 1.5s 304 - 1.5s < Mbbbb < 304 + 1.5s Signal: s 58 pb BR(f->hh)  0.33 BR(h->bb)  0.9 Eff  5% 4b QCD (PT>100 GeV): s(qq,gg->bbbb) 930 pb Eff  3% 837*103 events 22.5*103 events 30 fb-1 Simone Gennai SNS, INFN-Pisa

  21. What is missing? • Considering all QCD background sources • Considering resonant backgroud • Check other trigger strategy (using b-tag) Simone Gennai SNS, INFN-Pisa

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