Higgs Candidate Property Measurements with the Compact Muon Solenoid. Andrew Whitbeck * for the CMS Collaboration. Johns Hopkins University

Transcription

1 Higgs Candidate Property Measurements with the Compact Muon Solenoid Andrew Whitbeck * for the CMS Collaboration * Johns Hopkins University Rencontres de Moriond QCD, La Thuile, Italy March 14, 2013

2 Overview Higgs Candidate 126 GeV evidence observed in 5 channels Start constraining properties Spin-Parity (24.7/fb) ZZ, WW Mass measurement (17.3/fb) Coupling fits (17.3/fb) November

3 Spin-Parity Using kinematic distributions to distinguish different signal models Probe different amplitude structures Test compatibility of data with distinct models (Neyman-Pearson hypothesis testing) Null Hypothesis always SM Higgs J P Description 0 - CP-odd scalar 0 h + CP-even w/ HD operators 1 + Axial-vector 1 - Vector 2 m+ (gg) gg -> min coupling grav 2 m+ (qq) qq->min coupling grav models and MC event generator used described in arxiv:

4 Spin-Parity(ZZ) First results on 0- by CMS PRL. 110, (2013) P X taken from JHUGen 1,2 (signal) and MCFM 3 (qqzz) LO ME Calculations cross-check with analytical 1,2,4 and madgraph 5 1 arxiv: , 2 arxiv: , 3 arxiv: , 4 arxiv: , 5 arxiv:

5 D JP Distributions 0h+ 0- D bkg > gg2m+ qq2m+ 5

6 M ll [GeV] M ll [GeV] M ll [GeV] Spin-Parity (WW) m ll -m T plane also used to test gg->2m+ hypotheses M T [GeV] M T [GeV] M T [GeV] 6

7 Spin-Parity Results 0-0h+ gg->2m+->zz 1-1+ gg->2m+->ww qq2m+ 7

8 Spin-Parity Results HZZ fitted μ separation J P production comment expect (μ=1) obs. 0+ Obs. J P CL s 0- gg X Pseudoscalar 2.6σ (2.8σ) 0.5σ 3.3σ 0.16% 0h+ gg X Higher dim operators 1.7σ (1.8σ) 0.0σ 1.7σ 8.1% 2m+ gg X Minimal couplings 1.8σ (1.9σ) 0.8σ 2.7σ 1.5% 2m+ qq X Minimal couplings 1.7σ (1.9σ) 1.8σ 4.0σ <0.1% 1- qq X Exotic vector 2.8σ (3.1σ) 1.4σ >4.0σ <0.1% 1+ qq X Exotic axial-vector 2.3σ (2.6σ) 1.7σ >4.0σ <0.1% HWW fitted μ separation J P production comment expect (μ=1) obs. 0+ Obs. J P CL s 2m+ gg X Minimal couplings 1.8σ (2.4σ) 0.5σ 1.3σ 14% CL s = P(q>q0 alt)/p(q>q0 SMH) 8

9 Mixed Parity (ZZ) f a3 = A 3 2 /( A A 3 2 ) Expected Observed μ profiled f a3 = f a3 95% C.L. 9

10 Combined Results 10

11 Mass Measurement Combined mass using HZZ and Hγγ Resolutions of 1-2% signal strength for Hγγ, Hγγ +2j, and HZZ profiled (model independent) Results consistent when relative yields are fixed to SM m H = /- 0.4 (stat) +/- 0.4 (syst) GeV 11

12 Coupling Compatibility N(xx H yy) ~ σ(xx H) BR(H yy) ~ Γ xx Γ yy /Γ tot e.g. 8 parameters describing yields in 5 channels Γ WW, Γ ZZ, Γ γγ, Γ bb, Γ gg, Γ tt, Γ ττ, Γ tot Test compatibility through variations w/ respect to SM using scaling factors 1 Deviations from κ i =1 imply new physics 1 arxiv:

13 Signal Strength ggh VBFH VH tth H γγ H ZZ H WW H ττ H bb σ/ σ SM = /

14 R v -R f Best fit signal strength in VBF+VH production vs. ggh+tth production H ZZ 4l H μ qqh+vh μ qqh+vh μ ggh+tth μ ggh+tth 14

15 Hidden BSM Physics New physics can appear in loop diagrams: Effects Γ gg, Γ γγ and Γ tot Invisible decay effect total width Scale total width: BR BSM = Γ BSM /Γ tot 95% CL 15

16 Custodial Symmetry λ WZ = κ W / κ Z κ Z profiled All channels κ Z,κ f profiled 95% CL 95% CL Assume λ WZ =1 from now on 16

17 Fermion Universality 2-Higgs-Doublet models can affect up-type, down-type fermions differently leptons, quarks differently κ V and κ q (κ u ) profiled 95% CL 95% CL 17

18 Couplings (κ v,κ f ) κ f constrained >0 Sign of κ f driven by Hγγ: ακ V +βκ f 2 κ V =1: 95% CL κ f =1: 95% CL 18

19 Conclusions m H = /- 0.4 (stat) +/- 0.4 (syst) GeV σ/ σ SM =.88 +/ Data consistent with Custodial symmetry Fermion universality tests Fermionic and bosonic couplings expected from SM Higgs Data disfavors all alternative models tested thus far at 2σ CL except 0h+ (0-,1+,1-,gg->2m+,qq->2m+) 19

20 Thanks! For more information: CMS Higgs Combination PAS: CMS-PAS-HIG CMS Higgs ZZ4l PAS: CMS-PAS-HIG CMS Higgs WW(2l2ν) PAS: CMS-PAS-HIG CMS Hbb PAS: CMS-PAS-HIG CMS Hγγ PAS: CMS-PAS-HIG CMS Hττ PAS: CMS-PAS-HIG

21 BACKUP 21

22 References:ZZ Kinematics - Y. Gao et al., Spin determination of single-produced resonances at hadron colliders, Phys. Rev. D 81 (2010) , doi: /physrevd , arxiv: S. Bolognesi et al., On the spin and parity of a single-produced resonance at the LHC, Phys. Rev. D 86 (2012) , doi: /physrevd , arxiv: Y. Chen, N. Tran, and R. Vega-Morales, Scrutinizing the Higgs Signal and Background in the 2e2m Golden Channel, arxiv: J. M. Campbell, R. Ellis, and C. Williams, Vector boson pair production at the LHC, JHEP 07 (2011) 018, doi: /jhep07(2011)018, arxiv: P. Avery et al., Precision studies of the Higgs boson decay channel H \to ZZ* \to 4l with MEKD, accepted by Phys.Rev.D. (2012) arxiv: /13/

23 ZZ Measurements Loose selection to maximize signal efficiency Di-jet tagged and non di-jet tagged Sensitivity to VBF and VH/ttH production Full description of event kinematics For more details see previous talk on di-boson analyses: C. Ochando 3/13/

24 Sensitive to Production Mechanism ZZ Event Categories No di-jet Sensitive to Higgs Kinematics 3/13/2013 di-jet tagged For more details see previous talk on di-boson analyses: C. Ochando 24

25 ZZ Signal Strength σ/ σ SM = at m H =125.8 GeV 3/13/2013 For more details see previous talk on di-boson analyses: C. Ochando 25

26 Spin-0 Amplitude Most general spin-0 amplitude for X VV a 1 : SM Higgs (0 m+ ) a 2 : CP-even scalar w/ HD operators (0 h+ ) Contributes to Hγγ also a 3 : pseudoscalar (0 - ) Small correction from a3 in SM Higgs 3/13/

27 Spin-1 Amplitude Most general spin-1 amplitude for X VV b 1 : axial-vector (1 + ) B 2 : vector (1 - ) 3/13/

28 Spin-2 Amplitude Most general spin-2 amplitude for X VV Minimal coupling graviton made of all terms proportional to Λ 0 (g 1 =g 5 =1) 3/13/

29 Hypothesis Testing (ZZ) Testing data against large numbers of pseudoexperiments fixing μ to SM expectation fitting μ on data Expected separation taken from average type 1 and type 2 errors Observations interpreted by p-value of either distribution 3/13/

30 Hypothesis Testing (ZZ) Events are described by 2D histograms D bkg vs D 0- qqzz 0- SM Higgs 30

31 Hypothesis Testing (ZZ) Large deviations from 0+ and spin-1 models Driven by excess of events in tails of mass distributions Mass distributions differ considerably for spin-0 and spin-1 models Some events were already present in ICHEP 2012 dataset 3/13/

32 Kinematics Distributions Mz1 distributions are more distinct for different spin-1 and spin-2 models spin-1 and spin-2 KDs will provide more weight to events in tails of these distributions 3/13/

33 KD Correlations Strong correlation between non-scalar KDs 3/13/

34 WW Analysis 6 event categories (0-jet, 1-jet) x (ee,mumu,emu) 2D shape-based analysis (mt vs mll) For more details see previous talk on di-boson analyses: C. Ochando 3/13/

35 Combined Mass Combining 2 high resolution channels (ZZ, γγ) Branching ratios fixed to SM Higgs expectations Signal strength for Hγγ, Hγγ +2j, and HZZ treated as nuisances m H = /- 0.4 (stat) +/- 0.4 (syst) GeV 3/13/

36 Signal Strength σ/ σ SM = / All Channels consistent with SM All event classes consistent with SM 3/13/

37 Signal Strength Best fit signal strength in VBF+VH prod. vs. ggh+tth prod. mh = GeV Curves represent 68% CL contours 3/13/

38 Coupling (κ v,κ f ) κ f vs κ v by channel parameters constrained to be positive All channels consistent with SM Higgs expectation 3/13/

39 Coupling Measurements κ V κ b κ τ κ t κ g κ γ 3/13/