Higgs Property Measurements with the Compact Muon...

Higgs Candidate Property Measurements with the

Compact Muon Solenoid

Andrew Whitbeck*

for the CMS Collaboration

*Johns Hopkins University

Rencontres de Moriond QCD, La Thuile, ItalyMarch 14, 2013

Overview

• Higgs Candidate

– >7σ @ 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)

2Higgs Properties - Moriond QCD3/14/2013

November 2012

Spin-Parity

• Using kinematic distributions to distinguish different signal models

– Probe different amplitude structures


JP Description

0- CP-odd scalar

0h+ CP-even w/ HD operators

1+ Axial-vector

1- Vector

2m+ (gg) gg -> min coupling grav

2m+(qq) qq->min coupling grav

• Test compatibility of data with distinct models (Neyman-Pearson hypothesis testing)

• Null Hypothesis always SM Higgs

models and MC event generator used described in arXiv:1208.4018

Spin-Parity(ZZ)


• First results on 0- by CMS PRL. 110, 081803 (2013)

•PX taken from JHUGen1,2 (signal) and MCFM3 (qqZZ) LO ME Calculations• cross-check with analytical1,2,4 andmadgraph5

1arXiv:1208.4018, 2arXiv:1001.3396, 3arXiv:1105.0020, 4arXiv:1211.1959, 5arXiv:1210.0896

1-

qq2m+

1+

DJP Distributions


0h+

Dbkg>.5

gg2m+

0-

Spin-Parity (WW)• mll-mT plane also used to test gg->2m+ hypotheses


Mll

[Ge

V]

Mll

[Ge

V]

Mll

[Ge

V]

MT [GeV] MT [GeV]

MT [GeV]

Higgs Properties - Moriond QCD

Spin-Parity Results

73/14/2013

0-

1-

qq2m+

1+

0h+

gg->2m+->WW

gg->2m+->ZZ

fitted μ separation

JP production comment expect (μ=1) obs. 0+ Obs. JP CLs

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%

Spin-Parity Results


fitted μ separation

JP production comment expect (μ=1) obs. 0+ Obs. JP CLs

2m+ gg→X Minimal couplings 1.8σ (2.4σ) 0.5σ 1.3σ 14%

HZZ

HWW

CLs = P(q>q0|alt)/P(q>q0|SMH)

Mixed Parity (ZZ)

fa3 = |A3|2/(|A1|2+|A3|2)


fa3 = 0.00 +0.23-0.00

fa3<0.58 @ 95% C.L.

μ profiled

ExpectedObserved


Combined Results

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

mH = 125.8 +/- 0.4 (stat) +/- 0.4 (syst) GeV

Coupling Compatibility


N(xx→H→yy) ~ σ(xx→H) ∙ BR(H→yy) ~ Γxx ∙Γyy/Γtot

• 8 parameters describing yields in 5 channels

– ΓWW , ΓZZ , Γγγ , Γbb , Γgg , Γtt , Γττ , Γtot

• Test compatibility through variations w/ respect to SM using scaling factors1

– Deviations from κi =1 imply new physics

e.g.

1arXiv:1209.0040

Signal Strength


σ/ σSM = 0.88 +/- 0.21

ggH VBFH VH ttH

H→γγ

H→ZZ

H→WW

H→ττ

H→bb

Rv-Rf


• Best fit signal strength in VBF+VH production vs. ggH+ttH production

HZZ 4l H

μggH+ttHμggH+ttH

μq

qH

+VH

μq

qH

+VH

Hidden BSM Physics

• New physics can appear in loop diagrams:

– Effects Γgg, Γγγ and Γtot

• Invisible decay effect total width

– Scale total width:

• BRBSM = ΓBSM/Γtot


[0.00,0.62] @ 95% CL

Custodial Symmetry


λWZ = κW/ κZ

Assume λWZ =1 from now on

κZ profiledAll channelsκZ ,κf profiled

[0.67,1.55] @ 95% CL[0.57,1.65] @ 95% CL

Fermion Universality


• 2-Higgs-Doublet models can affect

– up-type, down-type fermions differently

– leptons, quarks differently

[0.00,2.11] @ 95% CL [0.45,1.66] @ 95% CL

κV and κq (κu) profiled

Couplings (κv,κf)

Sign of κf driven by Hγγ: |ακV+βκf|2

κV=1: [0.40,1.12] @ 95% CL

κf=1: [0.78,1.19] @ 95% CL


κf constrained >0

Conclusions

• 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+)


mH = 125.8 +/- 0.4 (stat) +/- 0.4 (syst) GeV

σ/ σSM = .88 +/- 0.21


Thanks!For more information:

CMS Higgs Combination PAS: CMS-PAS-HIG-12-045CMS Higgs ZZ4l PAS: CMS-PAS-HIG-13-002

CMS Higgs WW(2l2ν) PAS: CMS-PAS-HIG-13-003CMS Hbb PAS: CMS-PAS-HIG-12-044 CMS Hγγ PAS: CMS-PAS-HIG-13-001CMS Hττ PAS: CMS-PAS-HIG-12-004

BACKUP


References:ZZ Kinematics


- Y. Gao et al., “Spin determination of single-produced resonances at hadron colliders”, Phys. Rev. D 81 (2010) 075022, doi:10.1103/PhysRevD.81.075022, arXiv:1001.3396.-S. Bolognesi et al., “On the spin and parity of a single-produced resonance at the LHC”, Phys. Rev. D 86 (2012) 095031, doi:10.1103/PhysRevD.86.095031, arXiv:1208.4018.- Y. Chen, N. Tran, and R. Vega-Morales, “Scrutinizing the Higgs Signal and Background in the 2e2m Golden Channel”, arXiv:1211.1959.- J. M. Campbell, R. Ellis, and C. Williams, “Vector boson pair production at the LHC”, JHEP 07 (2011) 018, doi:10.1007/JHEP07(2011)018, arXiv:1105.0020.-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:1210.0896.

ZZ Measurements

• Loose selection to maximize signal efficiency

– Di-jet tagged and non di-jet tagged

• Sensitivity to VBF and VH/ttHproduction

– Full description of event kinematics


For more details see previous talk on di-boson analyses: C. Ochando

ZZ Event Categories


Sen

siti

ve t

o P

rod

uct

ion

Me

chan

ism

Sen

sitive to

Higgs K

ine

matics

di-jet tagged

No di-jet


ZZ Signal Strength


σ/ σSM = 0.91 +0.30 -0.24 at mH=125.8 GeV


Spin-0 Amplitude


• Most general spin-0 amplitude for X→VV

• a1 : SM Higgs (0m+)

• a2: CP-even scalar w/ HD operators (0h+)

• Contributes to Hγγ also

• a3: pseudoscalar (0-)

• Small correction from a3 in SM Higgs

Spin-1 Amplitude



• b1 : axial-vector (1+)

• B2: vector (1-)

Spin-2 Amplitude



• Minimal coupling graviton made of all terms proportional to Λ0 (g1=g5=1)

Hypothesis Testing (ZZ)

Testing data against large numbers of pseudo-experiments

fixing μ to SM expectation

fitting μ on data

Expected separation takenfrom average type 1 and type 2 errors

Observations interpretedby p-value of either distribution



• Events are described by 2D histograms

Dbkg vs D0-

30Higgs Properties - Moriond QCD

3/14/2013

qqZZ

SM Higgs

0-



• 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

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

KD Correlations


• Strong correlation between non-scalar KDs

WW Analysis

• 6 event categories

– (0-jet, 1-jet) x (ee,mumu,emu)

• 2D shape-based analysis (mT vs mll)



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


mH = 125.8 +/- 0.4 (stat) +/- 0.4 (syst) GeV

Signal Strength


σ/ σSM = 0.88 +/- 0.21All Channels consistent with SM All event classes consistent with SM

Signal Strength


• Best fit signal strength in VBF+VH prod. vs. ggH+ttH prod.

– mH = 125.8 GeV

– Curves represent 68% CL contours

Coupling (κv,κf)


• κf vs κv by channel

– parameters constrained to be positive

• All channels consistent with SM Higgs expectation

Coupling Measurements


κb κτ

κg

κV

κt

κγ

Higgs Property Measurements with the Compact Muon...

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