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FCNC Top2017 CMS

Davide Gerbaudo
September 21, 2017

FCNC Top2017 CMS

Search for top FCNC
Kirill Skovpen (VUB Brussel)
ATLAS and CMS Collaborations
Top 2017

Davide Gerbaudo

September 21, 2017
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  1. Search for top FCNC Kirill Skovpen (VUB Brussel) on behalf

    of the ATLAS and CMS Collaborations 10th International Workshop on Top Quark Physics, Braga, Portugal September 17-22, 2017
  2. 2 Flavour changing neutral currents Kirill Skovpen - 10th International

    Workshop on Top Quark Physics 2017/09/21 W− W+ Qj 2/3 Qi −1/3 Qk −1/3 Vji V † kj = Quark mass degeneracy → no FCNC = Glashow-Iliopoulos-Maiani (GIM) mechanism (1970) CKM matrix unitarity X j V † kj Vji q q2 m2 j = ki = m 2 s ¯ d Z/γ/H µ− µ+ K0 Flavour Changing Neutral Current
  3. t u/c g 3 CR7 changing money current Kirill Skovpen

    - 10th International Workshop on Top Quark Physics 2017/09/21 € 60 000 000
  4. 4 Top + gluon Top + Z Top + gamma

    Top + Higgs FCNC with top quarks Kirill Skovpen - 10th International Workshop on Top Quark Physics 2017/09/21
  5. 5 FCNC in SM and BSM SM 2HDM MSSM RS

    BR(t→cg) 10-12 10-8 - 10-4 10-7 - 10-6 10-10 BR(t→cZ) 10-14 10-10 - 10-6 10-7 - 10-6 10-5 BR(t→cɣ) 10-14 10-9 - 10-7 10-9 - 10-8 10-9 BR(t→cH) 10-15 10-5 - 10-3 10-9 - 10-5 10-4 K. Agashe et al., arXiv:1311.2028 (2013) Kirill Skovpen - 10th International Workshop on Top Quark Physics 2017/09/21 t u/c ɣ,g,Z,H ɣ,g,Z,H t u/c FCNC in decay FCNC in production ≈10M events ≈30M events @13TeV, 40 fb-1 ➪ Signal generation in Run 2 ATLAS: aMC@NLO+TopFCNC@NLO+Pythia8 CMS: MadGraph(LO)+Pythia8 Other models that predict enhanced FCNC also exist, e.g. 1709.01690 (not included here)
  6. 20 fb-1, 8 TeV 6 Search for top-gluon FCNC in

    single top Kirill Skovpen - 10th International Workshop on Top Quark Physics 2017/09/21 Eur. Phys. J. C (2016) 76:55 Search for top-gluon FCNC in single top events Event topology is exclusive top leptonic decay: isolated lepton, missing ET, = 1 b jet W+jets suppressed with NN Best limits on B(t→gc) B(t→gu) < 0.0040 % (obs) 0.0035 % (exp) B(t→gc) < 0.020 % (obs) 0.018 % (exp)
  7. 5+20 fb-1, 7+8 TeV 7 Search for top-gluon FCNC in

    single top Kirill Skovpen - 10th International Workshop on Top Quark Physics 2017/09/21 JHEP 02 (2017) 028 Search for top-gluon FCNC in single top + jet events Event topology: isolated lepton, missing ET, = 1 b jet, = 1 non-b jet ttbar suppressed with BNN Best limits on B(t→gu) B(t→gu) < 0.0020 % (obs) 0.0028 % (exp) B(t→gc) < 0.041 % (obs) 0.028 % (exp)
  8. 8 Kirill Skovpen - 10th International Workshop on Top Quark

    Physics 2017/09/21 Search for top-Z FCNC in ttbar and single top 20 fb-1, 8 TeV JHEP 07 (2017) 003 B(t→Zu) < 0.022 % (obs) 0.027 % (exp) B(t→Zc) < 0.049 % (obs) 0.118 % (exp) Search for top-Z FCNC in single top + ttbar events Event topology: three isolated leptons, missing ET, ≥ 1 b jet, ≥ 1 non-b jet (for ttbar) WZ+jets, fake, ttbar+V suppressed with BDT First top-Z search to include single top
  9. 50 100 150 200 250 300 350 400 [GeV] T

    p Leading lepton 0.6 0.8 1 1.2 1.4 Data / Bkg 10 20 30 40 50 60 70 Events ATLAS Preliminary -1 = 13 TeV, 36 fb s = 0) µ CR+SR fit ( Z CR t t Post-Fit Data Z t t WZ Other MC Non-prompt bWuZ → t t (BR = 0.017%) Bkg uncertainty 0 2 4 6 8 10 12 14 2 χ 0.6 0.8 1 1.2 1.4 Data / Bkg 10 20 30 40 50 60 Events ATLAS Preliminary -1 = 13 TeV, 36 fb s = 0) µ CR+SR fit ( Signal Region Post-Fit Data Z t t WZ Other MC Non-prompt bWuZ → t t (BR = 0.017%) Bkg uncertainty 50 100 150 200 250 300 350 400 [GeV] T p Leading lepton 0.6 0.8 1 1.2 1.4 Data / Bkg 20 40 60 80 100 120 140 160 180 200 Events ATLAS Preliminary -1 = 13 TeV, 36 fb s = 0) µ CR+SR fit ( Non-prompt lepton CR1 Post-Fit Data Z t t WZ Other MC Non-prompt bWuZ → t t (BR = 0.017%) Bkg uncertainty 50 100 150 200 250 300 350 400 [GeV] T p Leading lepton 0.6 0.8 1 1.2 1.4 Data / Bkg 50 100 150 200 250 300 Events ATLAS Preliminary -1 = 13 TeV, 36 fb s = 0) µ CR+SR fit ( Non-prompt lepton CR0 Post-Fit Data Z t t WZ Other MC Non-prompt bWuZ → t t (BR = 0.017%) Bkg uncertainty 60 80 100 120 140 160 180 200 220 [GeV] T m W boson 0.6 0.8 1 1.2 1.4 Data / Bkg 50 100 150 200 250 300 350 Events ATLAS Preliminary -1 = 13 TeV, 36 fb s = 0) µ CR+SR fit ( WZ CR Post-Fit Data Z t t WZ Other MC Non-prompt bWuZ → t t (BR = 0.017%) Bkg uncertainty 150 200 250 300 350 400 450 500 550 600 [GeV] llll m 0.6 0.8 1 1.2 1.4 Data / Bkg 10 20 30 40 50 60 70 Events ATLAS Preliminary -1 = 13 TeV, 36 fb s = 0) µ CR+SR fit ( ZZ CR Post-Fit Data ZZ Other MC Bkg uncertainty 9 Kirill Skovpen - 10th International Workshop on Top Quark Physics 2017/09/21 36 fb-1, 13 TeV Search for top-Z FCNC in ttbar Search for top-Z FCNC in ttbar events Event topology: three isolated leptons, missing ET, = 1 b jet, ≥ 1 non-b jet Simultaneous fit in CRs (WZ+jets, ZZ+jets, fake, ttbar+Z) and SR Best limits on B(t→Zq) 13 TeV SR ttZ CR WZ CR ZZ CR Fake CR1 Fake CR2
  10. 10 Kirill Skovpen - 10th International Workshop on Top Quark

    Physics 2017/09/21 36 fb-1, 13 TeV Search for top-Z FCNC in ttbar B(t→Zu) < 0.017 % (obs) 0.024 % (exp) B(t→Zc) < 0.023 % (obs) 0.032 % (exp) 13 TeV 0.01 0.02 0.03 0.04 0.05 uZ) [%] → BR(t 0 0.2 0.4 0.6 0.8 1 s CL Observed CLs Expected CLs - Median σ 1 ± Expected CLs σ 2 ± Expected CLs ATLAS Preliminary -1 = 13 TeV, 36 fb s 0.02 0.03 0.04 0.05 0.06 cZ) [%] → BR(t 0 0.2 0.4 0.6 0.8 1 s CL Observed CLs Expected CLs - Median σ 1 ± Expected CLs σ 2 ± Expected CLs ATLAS Preliminary -1 = 13 TeV, 36 fb s Also presented in poster by Archil Durglishvili
  11. 11 Kirill Skovpen - 10th International Workshop on Top Quark

    Physics 2017/09/21 20 fb-1, 8 TeV JHEP 04 (2016) 035 B(t→ɣu) < 0.013 % (obs) 0.019 % (exp) B(t→ɣc) < 0.200 % (obs) 0.170 % (exp) Search for top-ɣ FCNC in single top events Event topology: isolated muon, isolated photon, missing ET, ≤ 1 b jet W(+ɣ) suppressed with BDT Best and only limits on B(t→ɣq) Search for top-ɣ FCNC in single top
  12. 12 Kirill Skovpen - 10th International Workshop on Top Quark

    Physics 2017/09/21 36 fb-1, 13 TeV arXiv:1707.01404 H→ɣɣ 13 TeV Search for top-H FCNC in ttbar Search for top-H FCNC in ttbar events Event topology: = 2 isolated photons
 leptonic: isolated lepton, missing ET, = 1 b jets, ≥ 2 jets
 hadronic: no isolated leptons, ≥ 1 b jets, ≥ 4 jets Discrimination against non- resonant ɣɣ+jets, ttbar+ɣ, Wɣɣ with m(ɣɣ) Best limits on B(t→Hq) Mt ∉ [120,200] GeV Mt ∈ [120,200] GeV leptonic hadronic
  13. 13 Kirill Skovpen - 10th International Workshop on Top Quark

    Physics 2017/09/21 36 fb-1, 13 TeV arXiv:1707.01404 Search for top-H FCNC in ttbar B(t→Hu) < 0.24 % (obs) 0.17 % (exp) B(t→Hc) < 0.22 % (obs) 0.16 % (exp) H→ɣɣ 13 TeV
  14. 14 Kirill Skovpen - 10th International Workshop on Top Quark

    Physics 2017/09/21 Search for top-H FCNC in ttbar and single top 36 fb-1, 13 TeV TOP-17-003 H→bb Search for top-H FCNC in single top + ttbar events Event topology: isolated lepton, missing ET, ≥ 2 b jets, ≥ 1 non-b jet ttbar+jets suppressed with BDT First top-H search to include single top 13 TeV Hut Hct
  15. 15 Kirill Skovpen - 10th International Workshop on Top Quark

    Physics 2017/09/21 Search for top-H FCNC in ttbar and single top 36 fb-1, 13 TeV TOP-17-003 H→bb 13 TeV B(t→Hu) < 0.47 % (obs) 0.34 % (exp) B(t→Hc) < 0.47 % (obs) 0.44 % (exp) Also presented in poster by Predrag Cirkovic
  16. 16 Summary of top FCNC limits Kirill Skovpen - 10th

    International Workshop on Top Quark Physics 2017/09/21 BSM predictions Future projections
  17. 17 FCNC → unique playground for precise tests of the

    SM and to search for BSM physics 13 TeV data → significantly improve 8 TeV FCNC limits LHC is a top factory → a lot of opportunities for FCNC searches with top quarks Conclusion FCNC ! FCNC ! FCNC ! Kirill Skovpen - 10th International Workshop on Top Quark Physics 2017/09/21 LHC BSM
  18. 18 Kirill Skovpen - 10th International Workshop on Top Quark

    Physics 2017/09/21 Search for top-H FCNC in ttbar and single top 36 fb-1, 13 TeV TOP-17-003 H→bb 13 TeV
  19. 19 Kirill Skovpen - 10th International Workshop on Top Quark

    Physics 2017/09/21 Search for top-H FCNC in ttbar and single top 36 fb-1, 13 TeV TOP-17-003 H→bb 13 TeV
  20. 150 200 250 300 350 400 450 500 550 600

    [GeV] llll m 0.6 0.8 1 1.2 1.4 Data / Bkg 10 20 30 40 50 60 70 Events ATLAS Preliminary -1 = 13 TeV, 36 fb s = 0) µ CR+SR fit ( ZZ CR Pre-Fit Data ZZ Other MC Bkg uncertainty 60 80 100 120 140 160 180 200 220 [GeV] T m W boson 0.6 0.8 1 1.2 1.4 Data / Bkg 50 100 150 200 250 300 350 Events ATLAS Preliminary -1 = 13 TeV, 36 fb s = 0) µ CR+SR fit ( WZ CR Pre-Fit Data Z t t WZ Other MC Non-prompt bWuZ → t t (BR = 0.017%) Bkg uncertainty 50 100 150 200 250 300 350 400 [GeV] T p Leading lepton 0.6 0.8 1 1.2 1.4 Data / Bkg 20 40 60 80 100 120 140 160 180 Events ATLAS Preliminary -1 = 13 TeV, 36 fb s = 0) µ CR+SR fit ( Non-prompt lepton CR1 Pre-Fit Data Z t t WZ Other MC Non-prompt bWuZ → t t (BR = 0.017%) Bkg uncertainty 50 100 150 200 250 300 350 400 [GeV] T p Leading lepton 0.6 0.8 1 1.2 1.4 Data / Bkg 50 100 150 200 250 300 Events ATLAS Preliminary -1 = 13 TeV, 36 fb s = 0) µ CR+SR fit ( Non-prompt lepton CR0 Pre-Fit Data Z t t WZ Other MC Non-prompt bWuZ → t t (BR = 0.017%) Bkg uncertainty 0 2 4 6 8 10 12 14 2 χ 0.6 0.8 1 1.2 1.4 Data / Bkg 10 20 30 40 50 60 Events ATLAS Preliminary -1 = 13 TeV, 36 fb s = 0) µ CR+SR fit ( Signal Region Pre-Fit Data Z t t WZ Other MC Non-prompt bWuZ → t t (BR = 0.017%) Bkg uncertainty 50 100 150 200 250 300 350 400 [GeV] T p Leading lepton 0.6 0.8 1 1.2 1.4 Data / Bkg 10 20 30 40 50 60 70 Events ATLAS Preliminary -1 = 13 TeV, 36 fb s = 0) µ CR+SR fit ( Z CR t t Pre-Fit Data Z t t WZ Other MC Non-prompt bWuZ → t t (BR = 0.017%) Bkg uncertainty 20 Kirill Skovpen - 10th International Workshop on Top Quark Physics 2017/09/21 36 fb-1, 13 TeV TOPQ-2017-06 Search for top-Z FCNC in ttbar 13 TeV SR ttZ CR WZ CR ZZ CR Fake CR1 Fake CR2 pre-fit
  21. 21 Kirill Skovpen - 10th International Workshop on Top Quark

    Physics 2017/09/21 20 fb-1, 8 TeV Eur.Phys.J. C76 (2016) 12 B(t→Zq) < 0.07 % (obs) 0.08 % (exp) Search for top-Z FCNC in ttbar events Event topology: three isolated leptons, missing ET, ≤ 3 jets in total, ≤ 2 b jets WZ+jets, fake, ttbar+V suppressed by 2 top reconstruction selection Search for top-Z FCNC in ttbar
  22. 22 B(t→Hu) < 0.45 % (obs) 0.29 % (exp) B(t→Hc)

    < 0.46 % (obs) 0.25 % (exp) Kirill Skovpen - 10th International Workshop on Top Quark Physics 2017/09/21 Search for top-H FCNC in ttbar 8 TeV combination: H→ɣɣ, bb, WW/ 20 fb-1, 8 TeV JHEP 02 (2017) 079 20 fb-1, 8 TeV JHEP 12 (2015) 061 Next step: ATLAS+CMS combination? B(t→Hu) < 0.55 % (obs) 0.40 % (exp) B(t→Hc) < 0.40 % (obs) 0.43 % (exp)
  23. 23 Kirill Skovpen - 10th International Workshop on Top Quark

    Physics 2017/09/21 H→ɣɣ Search for top-H FCNC in ttbar events Event topology: = 2 isolated photons
 leptonic: isolated lepton, missing ET, ≥ 1 b jets, ≥ 2 jets
 hadronic: no isolated leptons, ≥ 1 b jets, ≥ 4 jets Discrimination against non-resonant ɣɣ+jets with m(ɣɣ) (hadronic) Search for top-H FCNC in ttbar 20 fb-1, 8 TeV JHEP 02 (2017) 079 20 fb-1, 8 TeV JHEP 06 (2014) 008 B(t→Hu) < 0.61 % (obs) 0.64 % (exp) B(t→Hc) < 0.56 % (obs) 0.42 % (exp) B(t→Hu) < 0.42 % (obs) 0.60 % (exp) B(t→Hc) < 0.47 % (obs) 0.67 % (exp) ATLAS CMS leptonic hadronic
  24. 24 Kirill Skovpen - 10th International Workshop on Top Quark

    Physics 2017/09/21 H→bb Search for top-H FCNC in ttbar events Event topology: isolated lepton, missing ET, 
 ≥ 2 b jets, ≥ 6 jets (ATLAS), ≥ 3 b jets, ≥ 4 jets (CMS) Ttbar+jets suppressed with likelihood discriminant (ATLAS) and ANN (CMS) Search for top-H FCNC in ttbar 20 fb-1, 8 TeV JHEP 02 (2017) 079 20 fb-1, 8 TeV JHEP 12 (2015) 061 B(t→Hu) < 0.61 % (obs) 0.64 % (exp) B(t→Hc) < 0.56 % (obs) 0.42 % (exp) B(t→Hu) < 1.92 % (obs) 0.84 % (exp) B(t→Hc) < 1.16 % (obs) 0.89 % (exp) ATLAS CMS
  25. 25 Kirill Skovpen - 10th International Workshop on Top Quark

    Physics 2017/09/21 H→WW/() Search for top-H FCNC in ttbar events Event topology: =2 (SS-only for CMS), =3 isolated leptons, missing ET, 
 ≥ 1 b jets, ≥ 3 jets (ATLAS), ≥ 2 jets (CMS) Ttbar(V)+jets (non-prompt, charge mis-id) background and signal fitted across the event categories Search for top-H FCNC in ttbar 20 fb-1, 8 TeV JHEP 02 (2017) 079 20 fb-1, 8 TeV JHEP 12 (2015) 061 B(t→Hu) < 0.78 % (obs) 0.57 % (exp) B(t→Hc) < 0.79 % (obs) 0.54 % (exp) B(t→Hu) < 0.86 % (obs) 0.82 % (exp) B(t→Hc) < 0.93 % (obs) 0.89 % (exp) ATLAS CMS
  26. 26 ZEUS Phys. Lett. B708 (2012) 27-36 H1 Phys. Lett.

    B678 (2009) 450 Search for ep → t e X at HERA Search for e+e- → t u/c at LEP2 L3 Phys. Lett. B549 (2002) 290-300 OPAL Phys. Lett. B521 (2001) 181-194 ALEPH Phys. Lett. B494 (2000) 33 DELPHI Phys. Lett. B590 (2004) 21-34 B(t→ɣq) ≲ 4 % B(t→Zq) ≲ 10 % B(t→ɣq) ≲ 0.5 % B(t→Zq) ≲ 4 % FCNC at LEP and HERA Top + Z/ gamma Top + Z/ gamma Kirill Skovpen - 10th International Workshop on Top Quark Physics 2017/09/21
  27. 27 Search for t → g q at DØ Phys.

    Lett. B693 (2010) 81-87 Search for t → Z q at CDF Phys. Rev. Lett. 101 (2008) 192002 FCNC at Tevatron B(t→gu) ≲ 0.02 % B(t→gc) ≲ 0.4 % B(t→Zq) ≲ 3.7 % Top + gluon Top + Z Kirill Skovpen - 10th International Workshop on Top Quark Physics 2017/09/21
  28. 28 Global fit for FCNC couplings G. Durieux et al.,

    arXiv:1412.7166 Parametrize top FCNC interactions with EFT approach at NLO Set bounds on top quark effective operators via χ2-based global fit a=1, a=2 white mark - single non- vanishing coefficient Kirill Skovpen - 10th International Workshop on Top Quark Physics 2017/09/21
  29. 29 Indirect probe of FCNH BaBar, Belle A. Fernandez et

    al., J.Phys.G37:085007,2010 XiaoJuan Wang et al., arxiv:1703.02691 F. Larios et al., Phys.Rev. D72 (2005) 057504 Kirill Skovpen - 10th International Workshop on Top Quark Physics 2017/09/21