with new hadronic top-tagging techniques T T.A. du Pree, P. Harris, - PowerPoint PPT Presentation

Search for top+ E miss with new hadronic top-tagging techniques T T.A. du Pree, P. Harris, J. Marrouche, N. Wardle [CERN] M. Cremonesi, B. Jayatilaka, J. Lewis, C.M. Suarez, N. Tran [Fermilab] D. Abercrombie, B. Allen, Z. Demiragli, G. G´ omez-Ceballos, D. Hsu, Y. Iiyama, D. Kovalskyi, B. Maier, S. Narayanan , C. Paus [MIT] K. Hahn, S. Sevova, K. Sung, M. Trovato [Northwestern] J. Pazzini, M. Zanetti, A. Zucchetta [Padova] MET+X, 24/02/2017 S. Narayanan (MIT) Hadronic monotop 24/02/2017 1 / 28

Analysis status ◮ Shown today: Summer16 MC and re-reco data ◮ AN and PAS will be updated in coming days with results presented today ◮ Early next week: first look at re-MINIAOD, updated JEC ◮ This talk: focus on updates since previous talk ◮ NLO signal model ◮ POG b -tag scale factors ◮ Additional data-driven backgrounds ◮ Categorization and optimization of selection S. Narayanan (MIT) Hadronic monotop 24/02/2017 2 / 28

Monotop via flavor-mixing neutral current u i χ Vector field that couples to q ¯ q ′ and decays to χ ¯ χ : V L int = V µ ¯ χγ µ ( g V χ + g A χ γ 5 ) χ χ ¯ u q u γ µ ( g V u + g A u γ 5 ) q u V µ + ¯ q d γ µ ( g V d + g A d γ 5 ) q d V µ + ¯ g t Definitions: ◮ V µ is the spin1 mediator ◮ g V χ and g A χ are the vector and axial-vector couplings of the DM to the mediator ◮ g V u and g A u are 3 × 3 flavor matrices and are the vector and axial-vector couplings of the up-type quarks ( q u ) to V ◮ g V d and g A d are the equivalent for down-type quarks ( q d ) S. Narayanan (MIT) Hadronic monotop 24/02/2017 3 / 28

Monotop via flavor-mixing neutral current ◮ This is an extension of DMSimp with flavor mixing implemented ◮ CMS and ATLAS have agreed to use this model for monotop ◮ SU (2) L mandates g V u − g A u = g V d − g A d ◮ Choice: g V u = g V d and g A u = g A d ◮ We choose to only turn on u - t mixing in g V,A u ⇒ monotop 13 TeV 13 TeV 13 TeV Arbitrary units Arbitrary units Arbitrary units CMS CMS CMS 0.3 Simulation Preliminary Simulation Preliminary Simulation Preliminary 0.3 0.4 V V V V V V g = 0.25, g = 1, m = 1 GeV g = 0.25, g = 1, m = 1 GeV g = 0.25, g = 1, m = 1 GeV χ χ χ q q q DM DM DM m = 0.3 TeV m = 0.3 TeV V m = 0.3 TeV V 0.3 V m = 0.5 TeV 0.2 m = 0.5 TeV m = 0.5 TeV V 0.2 V V m = 1.0 TeV m = 1.0 TeV V m = 1.0 TeV V V m = 1.5 TeV m = 1.5 TeV m = 1.5 TeV V 0.2 V V m = 2.25 TeV m = 2.25 TeV m = 2.25 TeV V V V 0.1 0.1 0.1 0 0 0 200 400 600 800 1000 0 5 10 200 400 600 800 1000 fat jet p (GeV) #AK4 jets PF MET (GeV) T S. Narayanan (MIT) Hadronic monotop 24/02/2017 4 / 28

Overview of objects Jets Tau veto ◮ AK4 jets for background suppression ◮ Decay mode finding and POG very loose ◮ b -tagged if passes CSVL isolation ◮ “Isolated” if no overlap with CA15 jet Electrons, muons, photons ◮ PUPPI CA15 jets to identify ◮ Latest POG IDs used for veto (SR) and hadronically-decaying tops selection (CRs) ◮ b -tagged if one subjet passes CSVL ◮ Loose (tight) top-tagged if BDT score is greater than 0.1 (0.45) ◮ Require 110 < m SD < 210 GeV S. Narayanan (MIT) Hadronic monotop 24/02/2017 5 / 28

Selection overview Preselection: ◮ Exactly one fatjet passing mass and BDT cuts ◮ Recoil greater than 250 GeV ◮ No identified τ leptons N iso Region(s) Main process(es) N e/µ N γ Fatjet b -tag b -tag → ( ℓ ) ν, t ¯ Signal Z → νν, W t → 0 0 0 > CSVL bqq ′ + b ( ℓ ) ν t → bqq ′ + bℓν t ¯ Single- ℓ (top) 1 0 1 > CSVL Single- ℓ ( W ) W → ℓν 1 0 0 < CSVL Dilepton Z → ℓℓ 2 0 − − Photon γ 0 1 − − NB: muon and electron regions are separate S. Narayanan (MIT) Hadronic monotop 24/02/2017 6 / 28

Top-tagger ◮ Using a new BDT constructed out of substructure variables (particularly energy correlation functions) ◮ Documentation available here , currently under review by JMAR -1 -1 36.6 fb (13 TeV) 36.6 fb (13 TeV) 2200 Events Events 2500 CMS Preliminary Data Data CMS Preliminary Data Data 2000 Z+jets Z+jets t t t t t t t t W+jets W+jets 1800 2000 W+jets W+jets Z+jets Z+jets Single t Single t Single t Single t 1600 Diboson Diboson Diboson Diboson 1400 QCD QCD QCD QCD 1500 1200 1000 1000 800 600 500 400 200 0 0 Data-Exp Data-Exp 0.4 1 0.8 0.6 0.4 0.2 0 0.2 0.4 0.6 0.8 1 0.4 1 0.8 0.6 0.4 0.2 0 0.2 0.4 0.6 0.8 1 Exp Exp 0.2 0.2 0 0 − − 0.2 0.2 − 0.4 − 0.4 − − − − − − − − − − 1 0.8 0.6 0.4 0.2 0 0.2 0.4 0.6 0.8 1 1 0.8 0.6 0.4 0.2 0 0.2 0.4 0.6 0.8 1 Top BDT Top BDT Muon t ¯ Dimuon selection: good agreement t selection: good agreement in shape S. Narayanan (MIT) Hadronic monotop 24/02/2017 7 / 28

Brief aside: t ¯ t modeling ◮ Our nominal simulation (Powheg) does not get the t ¯ t normalization correct ◮ Observed in other analyses that see high p T t ¯ t ◮ Ongoing studies to understand and fix the problem, see talk at TopModGen ◮ Attempting to request a large FXFX sample to use in the analysis Powheg Herwig amc@nlo FXFX -1 -1 36.6 fb (13 TeV) -1 36.6 fb (13 TeV) 36.6 fb (13 TeV) 4500 Events Events Events 5000 4000 Data Data Data Data CMS Preliminary Data Data CMS Preliminary CMS Preliminary 4000 t t t t t t t t t t t t 3500 W+jets W+jets W+jets W+jets W+jets W+jets Z+jets Z+jets Z+jets Z+jets 3500 Z+jets Z+jets 4000 Single t Single t Single t Single t 3000 Single t Single t Diboson Diboson Diboson Diboson 3000 Diboson Diboson QCD QCD QCD QCD QCD QCD 2500 3000 2500 2000 2000 2000 1500 1500 1000 1000 1000 500 500 0 0 Data-Exp 0 Data-Exp 0.4 60 80 100 120 140 160 180 200 220 240 Data-Exp 0.4 60 80 100 120 140 160 180 200 220 240 0.4 60 80 100 120 140 160 180 200 220 240 Exp Exp Exp 0.2 0.2 0.2 0 0 0 − − 0.2 − 0.2 0.2 − − 0.4 − 0.4 0.4 60 80 100 120 140 160 180 200 220 240 60 80 100 120 140 160 180 200 220 240 60 80 100 120 140 160 180 200 220 240 fatjet m [GeV] fatjet m [GeV] fatjet m [GeV] SD SD SD S. Narayanan (MIT) Hadronic monotop 24/02/2017 8 / 28

Top-tagging in signal events -1 -1 36.6 fb (13 TeV) 36.6 fb (13 TeV) a.u. a.u. 0.18 CMS Preliminary CMS Preliminary m m =2.5 TeV =2.5 TeV m m =2.5 TeV =2.5 TeV V V 0.08 V V 0.16 m m =1.5 TeV =1.5 TeV m m =1.5 TeV =1.5 TeV V V V V m =1 GeV, g =0.25, g =1 m =1 GeV, g =0.25, g =1 χ χ V V V V χ χ q q 0.07 0.14 m m =1.0 TeV =1.0 TeV m m =1.0 TeV =1.0 TeV V V V V 0.06 m m =0.5 TeV =0.5 TeV m m =0.5 TeV =0.5 TeV 0.12 V V V V m m =0.3 TeV =0.3 TeV m m =0.3 TeV =0.3 TeV 0.05 0.1 V V V V 0.04 0.08 0.03 0.06 0.04 0.02 0.01 0.02 0 0 − − − − − 0 50 100 150 200 250 300 350 400 1 0.8 0.6 0.4 0.2 0 0.2 0.4 0.6 0.8 1 fatjet m [GeV] Top BDT SD Generally observe higher m V ⇒ higher p t T ⇒ more merged top jets S. Narayanan (MIT) Hadronic monotop 24/02/2017 9 / 28

Signal region Tight Loose -1 -1 36.6 fb (13 TeV) 36.6 fb (13 TeV) Events/GeV Events/GeV CMS Preliminary m m =1.75 TeV, m =1.75 TeV, m =1 GeV =1 GeV 3 V V χ χ CMS Preliminary m m =1.75 TeV, m =1.75 TeV, m =1 GeV =1 GeV 10 V V χ χ 3 Z+jets Z+jets 10 Z+jets Z+jets t t t t t t t t 2 10 W+jets W+jets 2 10 W+jets W+jets ◮ Tight category has much Single t Single t Single t Single t 10 Diboson Diboson Diboson Diboson 10 higher t ¯ t contribution QCD QCD QCD QCD 1 1 than previous iterations of − 1 10 − 1 this analysis 10 − 2 10 − 2 10 − 3 10 − 3 10 300 400 500 600 700 800 900 1000 300 400 500 600 700 800 900 1000 PF MET [GeV] PF MET [GeV] S. Narayanan (MIT) Hadronic monotop 24/02/2017 10 / 28

Single µ ( W ) control region Tight Loose -1 36.6 fb (13 TeV) -1 36.6 fb (13 TeV) Events/GeV Events/GeV CMS Preliminary Data Data Data Data CMS Preliminary 3 10 W+jets W+jets 3 10 W+jets W+jets t t t t t t t t Z+jets Z+jets Z+jets Z+jets 10 2 ◮ Prefit agreement is 2 Single t Single t 10 Single t Single t Diboson Diboson Diboson Diboson reasonable QCD QCD 10 QCD QCD 10 ◮ One slightly suspicious bin 1 1 at 500 GeV − 1 10 − 1 10 ◮ NB: large t ¯ t − 2 10 − 2 10 contamination in tight − 3 10 − 3 10 Data-Exp 0.4 300 400 500 600 700 800 900 1000 Data-Exp 0.4 300 400 500 600 700 800 900 1000 Exp category Exp 0.2 0.2 0 0 − 0.2 − 0.2 − 0.4 − 0.4 300 400 500 600 700 800 900 1000 300 400 500 600 700 800 900 1000 µ PF U( ) [GeV] µ PF U( ) [GeV] S. Narayanan (MIT) Hadronic monotop 24/02/2017 11 / 28