Search for Higgs beyond the Standard Model with the ATLAS & CMS Detectors Rencontres du Vietnam, Quy Nhon Nikolina Ilic on behalf of the ATLAS and

Transcription

1 Search for Higgs beyond the Standard Model with the ATLAS & CMS Detectors Rencontres du Vietnam, Quy Nhon Nikolina Ilic on behalf of the ATLAS and CMS Collaborations Radboud University Aug 8, 2018

2 Outline Introduction Beyond Standard Model Higgs theories Results for recently published channels Focus on novel techniques Conclusion 2

3 Introduction Need to extend SM to address issues like hierarchy problem, quantum gravity, baryon asymmetry, dark matter/energy, neutrino masses Look for BSM physics by Looking for deviations from the SM in Higgs properties measurements Directly searching for beyond SM objects Additional Higgs bosons decaying to SM particles SM Higgs decays to BSM states (eg. invisible decays) 3

4 ATLAS Detector Introduction 4

5 Beyond Standard Model Higgs Theories SM Higgs doublet Additional Field EWS: Additional EW Singlet Model SM one scaler EW singlet Additional Higgs Bosons Neutral CP Even 5

6 Beyond Standard Model Higgs Theories SM Higgs doublet Additional Field EWS: Additional EW Singlet Model SM one scaler EW singlet Additional Higgs Bosons Neutral CP Even 2HDM: Two Higgs Doublet Model SM another Higgs doublet Neutral CP Even CP Odd Charged 6

7 Beyond Standard Model Higgs Theories SM Higgs doublet Additional Field EWS: Additional EW Singlet Model SM one scaler EW singlet Additional Higgs Bosons Neutral CP Even 2HDM: Two Higgs Doublet Model SM another Higgs doublet Neutral CP Even CP Odd Charged 2HDM + Singlet (complex) Model SM doublet & singlet Neutral CP Even CP Odd + 2HDM Higgses 7

8 Beyond Standard Model Higgs Theories SM Higgs doublet Additional Field EWS: Additional EW Singlet Model SM one scaler EW singlet Additional Higgs Bosons Neutral CP Even 2HDM: Two Higgs Doublet Model SM another Higgs doublet Neutral CP Even CP Odd Charged 2HDM + Singlet (complex) Model SM doublet & singlet Neutral CP Even CP Odd + 2HDM Higgses Higgs Triplet Model SM triplet Double Charged H ± ± + 2HDM Higgses 8

9 Beyond Standard Model Higgs Theories EWS significantly constrained by Run 1 Higgs measurements 2HDM: two Higgs doublets Φ 1 and Φ 2 7 parameters: m h, m H, m A, m H ±, m 12, tanβ, α Ratio of VEV of Φ 1 and Φ 2 h & H mixing angle Models motivated by bounds on FCNC Type I : fermions couple to Φ 2 Type II : up type quarks couple to Φ 2, down-type quarks & charged leptons couple to Φ 1. Eg: MSSM Run 1 SM Higgs results give big constraints on 2HDM. Data prefers alignment limit: cos(β α) = 0 9

10 tanβ Beyond Standard Model Higgs Theories 2HDM-Minimal Supersymmetric SM (MSSM) To reduce parameters define benchmarks defined: ± m h,mod : m h is close to 125 GeV hmssm : measured value of m h can be used to predict other masses In Run 1 excluded many regions of parameter space m A [GeV] 10

11 Neutral Heavy Higgs to bosons & fermions ATLAS WV lνqq, lνlν ZV llqq /ννqq ZZ 4l, llνν VV 2j Z/Wh (w h bb) ZH (H bb) γz γγ ττ 2l, lj, jj tt 4γ WH bb CMS ~36 fb TeV ZZ 4l, llqq, llνν γz bb ττ 2l, lj, jj Zh llττ Zh llbb ZA/H llbb γγ μμ ττ fb TeV 5fb fb TeV Legend Neutral Higgs to di-higgs hh bbγγ hh 4b hh WWγγ hh bbττ hh bbγγ hh 4b hh WW/ZZ +2b hh bbττ hh llγγ 11

12 Charged Higgs H ± ± ATLAS H ± τν H ± tb H ±± ll H ± cs VBF H ± WZ CMS H ± τν H ± tb H ± ZW H ± cs H ±± 4l/3lν ~36 fb TeV fb TeV 5fb TeV fb TeV Legend ATLAS CMS Higgs exotic with MET H γγ+met H bb+met hz INV (ll) H Z d Z d H Z (ll)+met hz INV (ll/bb ) hz INV +1/2γ hj INV +j VBF h INV hv INV (had) H γ+met H INV (1 jet) 12

13 Rare decays/ LVF ATLAS h(125) φ/ργ h(z) J/ψγ or ψ/(2s) or Υ(nS) h τμ / τe / eμ CMS h τμ ~36 fb TeV fb TeV 5fb TeV fb TeV Legend Higgs to light res. ATLAS aa jjγγ aa bbμμ aa 4b aa μμττ CMS aa μμττ aa bbττ aa 4τ, μμbb, μμττ aa 4μ 13

14 Neutral Heavy Higgs to bosons & fermions ATLAS WV lνqq, lνlν ZV llqq /ννqq ZZ 4l, llνν VV 2j Z/Wh (w h bb) ZH (H bb) H ± h bb γz γγ ττ 2l, lj, jj tt 4γ WH bb CMS ~36 fb TeV ZZ 4l, llqq, llνν γz bb ττ 2l, lj, jj Zh llττ Zh llbb ZA/H llbb γγ μμ ττ fb TeV 5fb fb TeV Legend Neutral Higgs to di-higgs hh bbγγ hh 4b hh WWγγ hh bbττ hh bbγγ hh 4b hh WW/ZZ +2b hh bbττ hh llγγ 14

15 Neutral Heavy Higgs to bosons WV lvqq Why this channel? Is unitarisation of WW scattering at high energy ensured ONLY by h? Prominent decay is to W/Z in many BSM models SM 15

16 Neutral Heavy Higgs to bosons WV lvqq Why this channel? Is unitarisation of WW scattering at high energy ensured ONLY by h? Prominent decay is to W/Z in many BSM models SM BSM q തq/ggF production Vector Boson Fusion (VBF) Search for H, Z /W, G kk 16

17 Neutral Heavy Higgs to bosons WV lvqq Search in resolved and boosted categories j (R=0.4) l resolved ν 17

18 Neutral Heavy Higgs to bosons WV lvqq Search in resolved and boosted categories j (R=0.4) J (R=1) l ν l ν l resolved boosted 18

19 Neutral Heavy Higgs to bosons WV lvqq Background: W+jets and t ҧ t taken from background-rich control region (CR) Signal regions (SR) and CR separated using jet mass, number of b-tagged jets, D 2 W + Jets CR m lνj l ν l ν l resolved boosted 19

20 Neutral Heavy Higgs to bosons WV lvqq Background: W+jets and t ҧ t taken from background-rich control region (CR) Signal regions (SR) and CR separated using jet mass, number of b-tagged jets, D 2 CR μ W+jets m lνj SR W+jets, t ҧ t from CR SR l ν l ν l resolved boosted m lνj 20

21 Neutral Heavy Higgs to bosons WV lvqq Background: W+jets and t ҧ t taken from background-rich control region (CR) Signal regions (SR) and CR separated using jet mass, number of b-tagged jets, D 2 p Ti R ij p Tj p TJ e 2 = 1 p TJ J p Ti p Tj R ij l ν l ν l resolved boosted 21

22 Neutral Heavy Higgs to bosons WV lvqq Background: W+jets and t ҧ t taken from background-rich control region (CR) Signal regions (SR) and CR separated using jet mass, number of b-tagged jets, D 2 p TJ e 2 = 1 p TJ J p Ti p Tj R ij 1-prong jet identification (quark-gluon) l ν l ν l resolved boosted 22

23 Neutral Heavy Higgs to bosons WV lvqq Background: W+jets and t ҧ t taken from background-rich control region (CR) Signal regions (SR) and CR separated using jet mass, number of b-tagged jets, D 2 p Tk p Tj p Ti R ij p TJ e 2 = 1 p TJ J p Ti p Tj R ij e 3 = 1 p TJ J σ p Ti p Tj p Tk R ij R ik R jk l ν l ν l resolved boosted 23

24 Neutral Heavy Higgs to bosons WV lvqq Background: W+jets and t ҧ t taken from background-rich control region (CR) Signal regions (SR) and CR separated using jet mass, number of b-tagged jets, D 2 p Ti R ij p Tj p TJ e 2 = 1 p TJ J p Ti p Tj R ij e 3 = 1 p TJ J σ p Ti p Tj p Tk R ij R ik R jk 2-, 3-prong jet identification (W/Z/H bosons) l ν l ν l resolved boosted 24

25 Neutral Heavy Higgs to bosons WV lvqq Background: W+jets and t ҧ t taken from background-rich control region (CR) Signal regions (SR) and CR separated using jet mass, number of b-tagged jets, D 2 p Ti R ij p Tj e 2 = 1 p TJ J p Ti p Tj R ij e 3 = 1 p TJ J σ p Ti p Tj p Tk R ij R ik R jk l ν l ν l resolved boosted D 2 = e 3 e

26 Neutral Heavy Higgs to bosons WV lvqq CERN-PH-EP Background: W+jets and ttҧ taken from background-rich control region (CR) Signal regions (SR) and CR separated using jet mass, number of b-tagged jets, D 2 p Ti R ij p Tj e 2 = 1 p TJ J p Ti p Tj R ij e 3 = 1 p TJ J σ p Ti p Tj p Tk R ij R ik R jk l ν l ν l resolved boosted D 2 = e 3 e

27 Neutral Heavy Higgs to bosons WV lvqq Final discriminating variable: transverse mass CERN-EP largest local excess : 2.7 σ 27

28 Neutral Heavy Higgs to bosons & fermions ATLAS WV lνqq, lνlν ZV llqq /ννqq ZZ 4l, llνν VV 2j Z/Wh (w h bb) ZH (H bb) γz γγ ττ 2l, lj, jj tt 4γ WH bb CMS ~36 fb TeV ZZ 4l, llqq, llνν γz bb ττ 2l, lj, jj Zh llττ Zh llbb ZA/H llbb γγ μμ ττ fb TeV 5fb fb TeV Legend Neutral Higgs to di-higgs hh bbγγ hh 4b hh WWγγ hh bbττ hh bbγγ hh 4b hh WW/ZZ +2b hh bbττ hh llγγ 28

29 Neutral Higgs to fermions ττ 2l, lj, jj BR A Why this channel? In MSSM heavy Higgs boson coupling to down-type fermions (τ, b) strongly enhanced for high tan β gluon-gluon fusion (ggf) associated b production BR A bb BR A ττ BR A tt BR(A μμ) + m h,mod tanβ = 10 m A [GeV] ± Search for hmssm, m h,mod 29

30 Neutral Higgs to fermions ττ 2l, lj, jj 30 Background: jets/leptons faking τ leptons SR and CR separated using number of b-tagged jets, transverse mass, D ζ In real ττ events e, ν τ H ζ τ μ, ν 30

31 Neutral Higgs to fermions ττ 2l, lj, jj Background: jets/leptons faking τ leptons SR and CR separated using number of b-tagged jets, transverse mass, D ζ D ζ = p ζ miss 0.85 p ζ visible Supresses W+jets and t ҧ t e, ν p ζ miss p ζ vis μ, ν CERN-EP H 2l 31

32 Neutral Higgs to fermions ττ 2l, lj, jj Final discriminating variable: transverse mass MC normalized from CR Data-driven method CERN-EP CERN-EP

33 Neutral Higgs to fermions ττ 2l, lj, jj 33

34 Neutral Heavy Higgs to bosons & fermions ATLAS WV lνqq, lνlν ZV llqq /ννqq ZZ 4l, llνν VV 2j Z/Wh (w h bb) ZH (H bb) γz γγ ττ 2l, lj, jj tt 4γ WH bb CMS ~36 fb TeV ZZ 4l, llqq, llνν γz bb ττ 2l, lj, jj Zh llττ Zh llbb ZA/H llbb γγ μμ ττ fb TeV 5fb fb TeV Legend Neutral Higgs to di-higgs hh bbγγ hh 4b hh WWγγ hh bbττ hh bbγγ hh 4b hh WW/ZZ +2b hh bbττ hh llγγ 34

35 Neutral Higgs to di-higgs hh bbγγ Why these channels? SM Di-Higgs production much lower than single Higgs production t/b t/b 35

36 Neutral Higgs to di-higgs hh bbγγ Why this channel? SM Di-Higgs production much lower than single Higgs production t/b t/b t/b Di-Higgs production enhanced in BSM models Resonant production: 2HDM, radion, G kk Non resonant production: modified h coupling hh bbγγ: low background, good mass resolution BR bb WW bb 33% WW 25% 4.6% ττ 7.4% 2.5% ZZ 3.1% 1.2% γγ 0.26% 0.10% 36

37 Neutral Higgs to di-higgs hh bbγγ To separate different SRs for better sensitivity use Multivariate analysis (MVA) CERN-EP Inputs: inputs are b-tagging variables, helicity angles, p γγ T /m γγjj, p jjt /m γγjj 37

38 Neutral Higgs to di-higgs hh bbγγ Background: γ +jets described using Bernstein polynomials Signal obtained by fitting MC in m jj m γγ plane CERN-EP Non resonant production < 24 x SM observed 38

39 Charged Higgs H ± ± ATLAS H ± τν H ± tb H ±± ll H ± cs VBF H ± WZ CMS H ± τν H ± tb H ± ZW H ± cs H ±± 4l/3lν ~36 fb TeV fb TeV 5fb TeV fb TeV Legend ATLAS CMS Higgs exotic with MET H γγ+met H bb+met hz INV (ll) H Z d Z d H Z (ll)+met hz INV (ll/bb ) hz INV +1/2γ hj INV +j VBF h INV hv INV (had) H γ+met H INV (1 jet) 39

40 Heavy Charged Higgs H ± H ± τν tb taunu Why these channels? H ± is in doublet/triplet models For m H ± > (<) m top, H ± produced with t (b) H ± to τν (tb) dominates below (above) top threshold ATLAS Run 1: H ± tb analysis excess of (2.4 σ) ± Test hmssm and m h,mod 4-flavour scheme 5-flavour scheme BR H ± tb BR H ± τν BR H ± cs BR(H ± μν) + m h,mod tanβ = 10 40

41 Heavy Charged Higgs H ± τν Background: jets/leptons misidentified as τ estimated using Fake Factors SR real τ h Tight BDT requirement To identify τ Find jet, match 1 or 3 tracks to it Boosted Decision Tree (BDT) - separate τ from jets that resemble τ using info on hadronic activity Likely-hood based veto separates τ from e 41

42 Heavy Charged Higgs H ± τν Background: jets/leptons misidentified as τ estimated using Fake Factors SR real τ h Tight BDT requirement F = probability of jet faking τ Region with jets that resemble (anti-τ h ) Loose BDT requirement 42

43 Heavy Charged Higgs H ± τν Background: jets/leptons misidentified as τ estimated using Fake Factors SR real τ h Region with jets that resemble (anti-τ h ) F = F multi j + F W+j Multi-jet region (g-initiated) F multi j = N pass N fail W+jets region (q-initiated) F W+j 43

44 Heavy Charged Higgs H ± τν Background: jets/leptons misidentified as τ estimated using Fake Factors SR real τ h Region with jets that resemble (anti-τ h ) F = α multi j α W+j F multi j + F W+j α multi j f multi j + α W+j f w+j Multi-jet region (g-initiated) W+jets region (q-initiated) f multi j = N g, template fit N g +N q in BDT(3p), tau width (1p) f w+j 44

45 Heavy Charged Higgs H ± τν Background: jets/leptons misidentified as τ estimated using Fake Factors SR real τ h Region with jets that resemble (anti-τ h ) F = α multi j α W+j F multi j + F W+j α multi j f multi j + α W+j f w+j Multi-jet region (g-initiated) W+jets region (q-initiated) CERN-EP N g f multi j =, template fit N g +N q in BDT(3p), tau width (1p) f w+j 45

46 Heavy Charged Higgs H ± H ± τν tb taunu BDT is discriminating variable Inputs: transverse mass, missing transverse energy, momentum of objects, separation between objects CERN-EP CERN-EP MC normalized from CR Fake-factor method H ± tb analysis excess went away 46

47 Charged Higgs H ± ± ATLAS H ± τν H ± tb H ±± ll H ± cs VBF H ± WZ CMS H ± τν H ± tb H ± ZW H ± cs H ±± 4l/3lν ~36 fb TeV fb TeV 5fb TeV fb TeV Legend ATLAS CMS Higgs exotic with MET H γγ+met H bb+met hz INV (ll) H Z d Z d H Z (ll)+met hz INV (ll/bb ) hz INV +1/2γ hj INV +j VBF h INV hv INV (had) H γ+met H INV (1 jet) 47

48 Higgs exotic with MET h(125) aa/z dark Z dark Look for 2HDM H aa process Dark sector in SM extensions provides DM candidate, explains positron excesses 4l final states have low background. Optimize for different mass regions 48

49 Rare decays/ LVF ATLAS h(125) φ/ργ h(z) J/ψγ or ψ/(2s) or Υ(nS) h τμ / τe / eμ CMS h τμ ~36 fb TeV fb TeV 5fb TeV fb TeV Legend Higgs to light res. ATLAS aa jjγγ aa bbμμ aa 4b aa μμττ CMS aa μμττ aa bbττ aa 4τ, μμbb, μμττ aa 4μ 49

50 Higgs to light res aa μμττ Main background: Jets misidentified as τ estimated from CR Signal and background parameterized by different functions (Voigt/ Gaussian, Bernstein polynomials) Fit to in dimuon mass (excellent resolution!) CMS-HIG CMS-HIG

51 Conclusions Many ATLAS & CMS searches for beyond Standard Model physics were explored No discoveries yet of BSM Higgs sector Significant excesses not found, but many stringent limits set in several models 51