II.- Exploring New Era of Higgs Physics

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II.- Exploring New Era of Higgs Physics

Higgs Physics (mostly) at LHC

HASCO Hadron Collider Physcis School

Marumi Kado

Laboratoire de l’Accélérateur Linéaire (LAL) and CERN

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Inaugural entrance of the Higgs boson in the

PDG particle listing !

Entrance of the H ⁰ in the PDG!

H ⁰

… in 2013

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h t

t Z

t t

t t t

Z

Z Z Z

Z

b s

W

h

µ µ h

W

W W

h t

t Z

t t

t t t

Z

Z Z Z

Z

b s

W

h

µ µ h

W

W W

Much more to Higgs Physics than LHC

Direct Search Programs

-‐  LEP

-‐  TeVatron -‐  SLC

-‐  Etc…

Indirect cosmology

-‐  Vacuum stability -‐  Higgs InﬂaAon -‐  Etc…

LHC

H ⁰

Indirect precision EW

Indirect Flavor

(Higgs penguin)

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LHC Higgs Physics Landscape Redeﬁned

Expansion of the Higgs Physics Program!

Precision

-‐  Mass and width -‐  Coupling properAes

-‐  Quantum numbers (Spin, CP) -‐  DiﬀerenAal cross secAons -‐  Oﬀ Shell couplings and width -‐  Interferometry

Is the SM minimal?

-‐  2 HDM searches

-‐  MSSM, NMSSM searches -‐  Doubly charged Higgs bosons

Tool for discovery

-‐  Portal to DM (invisible Higgs) -‐  Portal to hidden sectors

-‐  Portal to BSM physics with H⁰ in the ﬁnal state (ZH⁰, WH⁰, H⁰H⁰)

*Disclaimer: Not all subjects will be covered in this talk

Rare decays

-‐  Zγ

-‐  Muons µµ -‐  LFV µτ, eτ

-‐  J/Ψγ, ZΥ, etc…

H ⁰

…and More!

-‐  FCNC top decays -‐  Di-‐Higgs producAon

-‐  Trilinear couplings prospects

-‐  Etc… ₄

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g

t t

W, Z W, Z

q

q g

g

q

(a) (b) q

(c) (d)

H

H H

H b

b

H b

t

q q

H b

t q q

W W

Higgs Production Modes

[TeV]

s

7 8 9 10 11 12 13 14

H+X) [pb]A(pp m

10-1

1 10 102

LHC HIGGS XS WG 2013

H (NNLO+NNLL QCD + NLO EW) pp A

H (NNLO QCD + NLO EW) q

A q pp

WH (NNLO QCD + NLO EW) pp A

ZH (NNLO QCD + NLO EW) A

pp

H (NLO QCD) tt

pp A

g

t

W, Z t W, Z

q

q g

g

q

(a) (b) q

(c) (d)

H

H H

H

g

t

W, Z t W, Z

q

q g

g

q

(a) (b) q

(c) (d)

H

H H

H g

g

t

W, Z t W, Z

q

q g

g

q

(a) (b) q

(c) (d)

H

H H

H

g

t

W, Z t W, Z

q

q g

g

q

(a) (b) q

(c) (d)

H

H H

H

Gluon fusion process

Vector Boson Fusion

W and Z Associated Production NNnLO ~O(10%)

Two forward jets and a large rapidity gap

NLO TH uncertainty ~O(5%)

NNLO TH uncertainty ~O(5%)

Top Assoc. Prod.

~0.5 M events produced

~40 k events produced

~3 k evts produced

tH

B-quark Assoc. Prod.

κ for m_H = 125.5 GeV

~5 k evts produced ₅

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H H

γ

γ γ

γ

W t

Higgs Decay Channels

[GeV]

MH

120 121 122 123 124 125 126 127 128 129 130

Higgs BR + Total Uncert

10-4

10-3

10-2

10-1

1

b b

o o

µ µ

c c gg

a a ZZ WW

Za

- Dominant: bb (57%)

- ττ channel (6.3%)

- The γγ channel (0.2%) - WW channel (22%)

- ZZ channel (3%)

- The µµ channel (0.02%) - cc channel (3%)

Extremely difficult

- The Zγ (0.2%)

6

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QCD

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QCD

Testing predictions over 8 orders of magnitude !

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) [nb]

l!

"

B( W WX ) #

"

( pp

$

0 2 4 6 8 10 12

= 7 TeV s at 36 pb-1

CMS

[with PDF4LHC 68% CL uncertainty]

NNLO, FEWZ+MSTW08 prediction 0.52 nb 10.44 ±

e!

"

W

lumi nb 0.42

syst± 0.17

stat± 0.03 10.48 ±

! µ

"

W

lumi nb 0.41

syst± 0.16

stat± 0.03 10.18 ±

(combined)

l!

"

W

lumi nb 0.41

syst± 0.13

stat± 0.02

± 10.31

) [nb]

l!

"

B( W WX ) #

"

( pp

$

0 2 4 6 8 10 12

EW

) [GeV]

µ M(µ ]-1 [GeVµµ/dM! d Z!1/

10-6

10-5

10-4

10-3

10-2

10-1

1

15 30 60 120 200 600

data

NNLO, FEWZ+MSTW08 uncertainty on modeling

CMS preliminary = 7 TeV s at 36 pb-1

µ µ

"

#* Z/

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[pb] totσProduction Cross Section,

10-1

1 10 102

103

104

105

CMS

July 2013

W

≥1j

≥2j

≥3j

≥4j

Z

≥1j

≥2j

≥3j

≥4j

> 30 GeV

jet

ET

| < 2.4 η jet

|

Wγ

> 15 GeV

γ

ET

,l) > 0.7 R(γ Δ

Zγ

WW+WZ WW

WZ ZZ

WVγ

36, 19 pb-1 5.0 fb^-1 5.0 fb^-1 4.9 fb-1

3.5 fb-1

4.9 fb-1

19.6 fb-1

19.3 fb-1

JHEP 10 132 (2011) JHEP 01 010 (2012) SMP-12-011 (W/Z 8 TeV)

EWK-11-009 EPJC C13 2283 (2013) (WV) SMP-12-006 (WZ), 12-005 (WW7), 13-005(ZZ8) JHEP 1301 063 (2013) (ZZ7), PLB 721 190 (2013) (WW8)

SMP-013-009

CMS 95%CL limit 7 TeV CMS measurement 8 TeV CMS measurement 7 TeV Theory prediction 8 TeV Theory prediction

Overview of Cross Sections

Expected Standard Model and Higgs Productions

Theory and simulation “Next-to…” revolution :

-  NNLO PDFs sets

-  Calculations at unprecedented order in perturbation theory -  Parton Shower (and Matrix Element matching) improvements

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[pb] totσProduction Cross Section,

10-1

1 10 102

103

104

105

CMS

July 2013

W

≥1j

≥2j

≥3j

≥4j

Z

≥1j

≥2j

≥3j

≥4j

> 30 GeV

jet

ET

| < 2.4 η jet

|

Wγ

> 15 GeV

γ

ET

,l) > 0.7 R(γ Δ

Zγ

WW+WZ WW

WZ ZZ

WVγ

36, 19 pb-1 5.0 fb^-1 5.0 fb^-1 4.9 fb-1

3.5 fb-1

4.9 fb-1

19.6 fb-1

19.3 fb-1

JHEP 10 132 (2011) JHEP 01 010 (2012) SMP-12-011 (W/Z 8 TeV)

EWK-11-009 EPJC C13 2283 (2013) (WV) SMP-12-006 (WZ), 12-005 (WW7), 13-005(ZZ8) JHEP 1301 063 (2013) (ZZ7), PLB 721 190 (2013) (WW8)

SMP-013-009

CMS 95%CL limit 7 TeV CMS measurement 8 TeV CMS measurement 7 TeV Theory prediction 8 TeV Theory prediction

Overview of Cross Sections

Expected Standard Model and Higgs Productions

0.1 1 10

10^-7 10^-6 10^-5 10^-4 10^-3 10^-2 10^-1 10⁰ 10¹ 10² 10³ 10⁴ 10⁵ 10⁶ 10⁷ 10⁸ 10⁹

WJS2010

!_jet(E_T^jet > 100 GeV)

!_jet(E_T^jet > "s/20)

!_Higgs(M_H=120 GeV) 200 GeV

LHC Tevatron

events / sec for L = 1033 cm-2 s-1

!_b

!_tot

proton - (anti)proton cross sections

!_W

!_Z

!_t

500 GeV

!!!!"nb#

"s (TeV) Theory and simulation “Next-to…” revolution :

-  NNLO PDFs sets

-  Calculations at unprecedented order in perturbation theory -  Parton Shower (and Matrix Element matching) improvements

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Signal (SM_{126
GeV}) Signal purity

s/b Main

backgrounds ProducAon 7 & 8 TeV

~450 2% -‐ 60% γγ,γj and jj Hgg, VBF, VH 4.9 & 20.7 k^-‐1

γγ channel basic facts sheet :

!

L dt

H → γγ ^Update

Since “Discovery Paper”

PLB 716

ATLAS-CONF-2013-012

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Signal Signal Purity

s/b Main

~16 ~1.5 ZZ, Z+jets, top ggH, VBF & VH 4.9 ^& 20.7 k^-‐1

4l channel basic facts sheet :

!

L dt

H → 4e candidate (m

_4e

~ 124 GeV)

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H → 4l Update H → 4l Single Highest Purity Candidate Event ( 2e2µ )

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Signal Sig. Purity s/b Main backgrounds ProducAon 7 & 8 TeV

~250 ~5%-‐40% WW, W+jets, top, etc… ggH & VBF 25k^-‐1

WW channel basic facts sheet :

!

L dt 0,1, 2 jet Channel

H → WW

⁽

*

⁾

ll + 2 ν

ATLAS-‐CONF-‐2013-‐030

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Signal (SM) Signal purity

s/b Main

~330 0.3% -‐ 30% ZZ, Z+jets, top VBF, Hgg, VH 4.9 & 13 k^-‐1

ττ channel basic facts sheet :

!

L dt

H → τ_hadτ_had candidate in VBF channel (m_MMC = 131 GeV)

H → ττ

R

eoptimised 7+8 TeV analysis

ATLAS-‐CONF-‐2012-‐160

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Signal (SM) Signal purity

s/b Main backgrounds ProducAon 7 & 8 TeV

~50 ~1% -‐ 10% Wbb,Zbb, top, etc… VH 4.9 ^& 13 k^-‐1

VH(bb) channel basic facts sheet :

!

L dt

VH production with H → bb

Combined and reoptimised 7+8 TeV analysis

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Yet another random example!

H ! !!

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Background From jets

Signal

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20

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Interesting Facts about the γγ Channel

- If observed implies that it does not originate from spin 1 : Landau-Yang theorem

- Main production and decay processes occur through loops :

… Not so obviously enhanced (e.g. SM4)

known at NNnLO, still rather large uncertainty O(10%)

A priori potentially large possible enhancement…

Seldom larger yields : e.g. NMSSM (U. Ellwanger et al.) up to x6, large stau mixing (M.

Carena et al.), Fermiophobia…

- High mass resolution channel

- If observed implies that its Charge Conjugation is +1

1.6 ! A

_W²

" 0.7 ! A

_t

A

_W

+ 0.1! A

_t²

Excellent probe for new physics !

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Performing analysis with categories

-  9 (central/forward and converted/not converted photons, p_Tt (γγ)) -  +3 (low mass di-jet, lepton and MET disentangling VH)

-  +2 (two 2-jet VBF categories MVA)

Improving Sensitivity and Probing Other Production Modes

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H → 4l Update Why Categories?

Let’s take a simple example with two categories:

- C1: s=12 and b=60 - C2: s=18 and b=40

Inclusively we have a significance of 3 Separating in two categories:

- C1 2.85 σ - C2 1.55 σ

Combined significance: 3.24

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Illustration of the Impact of Categories

ln(1+ s

_i

b

_i

)

Unweighted Weighted

Using constant weight per category (based on expected signal and background in each

category i) :

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Panorama of Higgs Analyses

Channel categories

ggF VBF VH nH

γγ ZZ (llll) WW (lnln)

ττ bb

Zγ

µµ Invisible

g

t

W, Z t W, Z

q

q g

g

q

(a) (b) q

(c) (d)

H

H H

H

g

t

W, Z t W, Z

q

q g

g

q

(a) (b) q

(c) (d)

H

H H

H g

g

t

W, Z t W, Z

q

q g

g

q

(a) (b) q

(c) (d)

H

H H

H

g

t

W, Z t W, Z

q

q g

g

q

(a) (b) q

(c) (d)

H

H H

H

25

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Panorama of Higgs Analyses

Channel categories

ggF VBF VH nH

γγ ✓ ✓ ✓ ✓

ZZ (llll) ✓ ✓ ✓ ✓

WW (lnln) ✓ ✓ ✓ ✓

ττ ✓ ✓ ✓

bb ✓ ^✓ ^✓

Zγ ✓ ✓

µµ ✓ ✓

Invisible ✓ ✓ ✓

g

t

W, Z t W, Z

q

q g

g

q

(a) (b) q

(c) (d)

H

H H

H

g

t

W, Z t W, Z

q

q g

g

q

(a) (b) q

(c) (d)

H

H H

H g

g

t

W, Z t W, Z

q

q g

g

q

(a) (b) q

(c) (d)

H

H H

H

g

t

W, Z t W, Z

q

q g

g

q

(a) (b) q

(c) (d)

H

H H

H

26

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Statistical Interpretation

How to read Higgs Search Plots

Hypothesis testing using the Profile likelihood ratio…

L( µ ^, ! ) = f

_b

"

_b

^(M

_##

) + f

_s

"

_s

^(M

_##

⁾

f _s ! µ

Simplified

Likelihood Definition:

n

_s

= µ! ^BrL "

Relates to Higgs mass hypothesis

Global coherent factor

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0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

10

0 1 2 3 4 5 6 7 8 9

!

-2 l n "( ! )

!# !

_test

q

_μ

q

₀

likelihood ratio without profiling

How to Read Higgs Exclusion Limits Plots

!

_µ

= ! ⁽ µ ^, " ) = L( µ ^{, ˆ} " ^ˆ ⁽ µ ⁾⁾

L( ˆ µ ^{, ˆ} " ⁾ q _µ = !2 ln ! _µ

Signal likeliness

Background likeliness

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H

⁰

Summary and inputs to the combination

Channel categories

ATLAS CMS

µ ( at 125.5 GeV) Z exp Z obs M (GeV) µ Z exp Z obs M (GeV)

γγ 1.5±0.3 4.1 7.4 126.8±0.2±0.7 0.8±0.3 3.9 6.7 125.4±0.5±0.4

ZZ (llll) 1.5±0.4 4.4 6.6 124.3±0.5±0.5 0.9±0.3 7.1 3.2 125.8±0.5±0.2

WW (lnln) 1.0±0.3 3.8 3.8 - 5.3 3.9 -

ττ 0.8±0.7 1.6 1.1 - 1.1±0.4 2.6 2.8 125 ⁺⁹_-7

W,Z H (bb*) -0.4±1.0 1.0 0.0 - 2.1 2.1 -

Combination 1.30±0.20 7.3 10 125.5±0.2±0.6 0.80±0.14 - - 125.7±0.3±0.3

*CMS also uses nH in the

combinaAon from 1303.0763

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Digression on Information Format

µ=1

Sub-channel signal strengths

Production mode signal strengths (per channel)

µ=0 µ=0 µ=1

n

_s^c

= µ

ⁱ

!

_SMⁱ

! A

^ic

! "

^ic

i"{ggF,VBF,VH ,ttH }

#

$

% && '

( )) ! µ

^f

Br

^f

! L

^c

(31)

pp

total 80µb⁻¹

W

total 35 pb⁻¹

Z

total 35 pb⁻¹

t¯t

total 4.6 fb⁻¹

20.3 fb⁻¹

t_t−chan

total 4.6 fb⁻¹

20.3 fb⁻¹

WW+WZ total 4.7 fb⁻¹

WW

total 4.6 fb⁻¹

20.3 fb⁻¹

HggF total 4.8 fb⁻¹

20.3 fb⁻¹

Wt

total 2.0 fb⁻¹

20.3 fb⁻¹

WZ

total 4.6 fb⁻¹

13.0 fb⁻¹

ZZ

total 4.6 fb⁻¹

20.3 fb⁻¹

HVBF total 20.3 fb⁻¹

t¯tW

total 20.3 fb⁻¹

t¯tZ

total 20.3 fb⁻¹

σ[pb]

10⁻¹ 1 10¹ 10² 10³ 10⁴ 10⁵ 10⁶ 10¹¹

LHC pp √

s = 7 TeV Theory Data

LHC pp √

s= 8 TeV Theory Data

Standard Model Total Production Cross Section Measurements Status: July 2014

ATLAS Preliminary Run 1 √

s = 7, 8 TeV

Overview of Cross SecAons

Past decade tremendous progresses in theory calculaAons and simulaAon “Next-‐to…

revoluAon”

Processes are simulated to an unprecedented level of accuracy

Number of events selected in full 2010-‐2012 dataset

W (lν) ~ 100 M Z (ll) ~ 10 M n (l+X) ~ 0.4 M

(top factory)

-‐  Test Standard Model

predicAons at 7 and 8 TeV

-‐  Calibrate the detector

31

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pp

total 80µb⁻¹

W

total 35 pb⁻¹

Z

total 35 pb⁻¹

t¯t

total 4.6 fb⁻¹

20.3 fb⁻¹

t_t−chan

total 4.6 fb⁻¹

20.3 fb⁻¹

WW+WZ total 4.7 fb⁻¹

WW

total 4.6 fb⁻¹

20.3 fb⁻¹

HggF total 4.8 fb⁻¹

20.3 fb⁻¹

Wt

total 2.0 fb⁻¹

20.3 fb⁻¹

WZ

total 4.6 fb⁻¹

13.0 fb⁻¹

ZZ

total 4.6 fb⁻¹

20.3 fb⁻¹

HVBF total 20.3 fb⁻¹

t¯tW

total 20.3 fb⁻¹

t¯tZ

total 20.3 fb⁻¹

σ[pb]

10⁻¹ 1 10¹ 10² 10³ 10⁴ 10⁵ 10⁶ 10¹¹

LHC pp √

s = 7 TeV Theory Data

LHC pp √

s= 8 TeV Theory Data

Standard Model Total Production Cross Section Measurements Status: July 2014

ATLAS Preliminary Run 1 √

s = 7, 8 TeV

Overview of Cross SecAons

Past decade tremendous progresses in theory calculaAons and simulaAon “Next-‐to…

revoluAon”

Processes are simulated to an unprecedented level of accuracy

Number of events selected in full 2010-‐2012 dataset

W (lν) ~ 100 M Z (ll) ~ 10 M n (l+X) ~ 0.4 M

(top factory)

-‐  Test Standard Model

predicAons at 7 and 8 TeV

-‐  Calibrate the detector Assumes SM branching fracAons HggF

32

ATL-‐COM-‐PHYS-‐2014-‐702

(33)

The Natural Width of the Higgs Boson

Is small therefore small couplings to the Higgs can be easily visible: tool for discovery!

At LHC only cross secAon x branching raAo, no direct access to the Higgs total cross secAon (unlike e⁺e^-‐ collider from recoil mass spectrum)

-‐ Direct measurement (on-‐shell) with the ZZ(4l) and γγ channels [obs. (exp.)]:

Γ_4l < 2.6 (3.5) GeV [exp. 6.5 for µ=1] and Γ_γγ <5.0 (6.2) GeV

-‐ Only measure raAo of couplings or coupling modiﬁers with speciﬁc assumpAons -‐ Coupling properAes measurements

-‐ Constraints from invisible (and exoAc decays)

Total width: Interference in diphoton (SM shix of approximately 30 MeV) Use pT dependence of shix

(~200 MeV limit expected for 3 ab^-‐1) Total width:

Through oﬀ shell couplings

!

_SM

= 4.2 MeV

ATL-‐PHYS-‐PUB-‐2013-‐014

33

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First step towards an global EFT analysis: InterpreAng our Data

n

_s^c

= µ µ

ⁱ

!

_SMⁱ

! A

^ic

! "

^ic

i"{ processes}

$ #

% && '

( )) ! µ

^f

^Br

^f

! L

^c

From the number of signal events ﬁned in analysis categories

34

(35)

-‐  Link to an eﬀecAve Lagrangian and use scale factors

First step towards an global EFT analysis: InterpreAng our Data

n

_s^c

= µ µ

ⁱ

!

_SMⁱ

! A

^ic

! "

^ic

i"{ processes}

$ #

% && '

( )) ! µ

^f

^Br

^f

! L

^c

35

(36)

First step towards an global EFT analysis: InterpreAng our Data

For example, the main contribuAon (ggF) to the gg channel can be wrinen as (under the assumpAon that couplings to SM parAcles are SM):

-‐  Assuming narrow width approximaAon

-‐  Assume the same tensor structure of the SM Higgs boson : J^CP = 0⁺⁺

n

_s^c

= µ µ

ⁱ

!

_SMⁱ

! A

^ic

! "

^ic

_"²

+ 0.91

₃₆

(37)

First step towards an global EFT analysis: InterpreAng our Data

For example, the main contribuAon (ggF) to the gg channel can be wrinen as (under the assumpAon that no BSM in the loops):

-‐  Assuming narrow width approximaAon

-‐  Assume the same tensor structure of the SM Higgs boson : J^CP = 0⁺⁺

n

_s^c

= µ µ

ⁱ

!

_SMⁱ

! A

^ic

! "

^ic

i"{ processes}

$ #

% && '

( )) ! µ

^f

^Br

^f

"

!

_SM

(38)

g

t t

W, Z W, Z

q

q g

g

q

(a) (b) q

(c) (d)

H

H H

H b

b

H b

t

q q

H b

t q q

W W

Higgs Production Modes

[TeV]

s

7 8 9 10 11 12 13 14

H+X) [pb]A(pp m

10-1

1 10 102

H (NNLO+NNLL QCD + NLO EW) pp A

H (NNLO QCD + NLO EW) q

A q pp

WH (NNLO QCD + NLO EW) pp A

ZH (NNLO QCD + NLO EW) A

pp

H (NLO QCD) tt

pp A

g

t

W, Z t W, Z

q

q g

g

q

(a) (b) q

(c) (d)

H

H H

H

g

t

W, Z t W, Z

q

q g

g

q

(a) (b) q

(c) (d)

H

H H

H g

g

t

W, Z t W, Z

q

q g

g

q

(a) (b) q

(c) (d)

H

H H

H

g

t

W, Z t W, Z

q

q g

g

q

(a) (b) q

(c) (d)

H

H H

H

Gluon fusion process

Vector Boson Fusion

W and Z Associated Production NNnLO ~O(10%)

Two forward jets and a large rapidity gap

NLO TH uncertainty ~O(5%)

NNLO TH uncertainty ~O(5%)

Top Assoc. Prod.

~0.5 M events produced

~3 k evts produced

tH

! 3.3"!_W² # 5.1"!_t!_W + 2.8 "!_t²

! !

_t²

! !

_V²

! !

_V²

!_g !1. " 06!_t² # 0.07 "!_t!_b + 0.01"!_b²

! !

_b²

B-quark Assoc. Prod.

κ for m_H = 125.5 GeV

~5 k evts produced ₃₈

(39)

H H

γ

γ γ

γ

W t

Higgs Decay Channels

[GeV]

MH

120 121 122 123 124 125 126 127 128 129 130

Higgs BR + Total Uncert

10-4

10-3

10-2

10-1

1

b b

o o

µ µ

c c gg

a a ZZ WW

Za

39

(40)

Main results I : Probing the coupling to SM particles

-  By convention sign on the fermion yukawa strength multiplier

(relying on the γγ strength primarily)… ambiguity inspired tH analyses -  Checking the direct and indirect couplings to fermions

-  Checks of specific composite models

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Main results II : Probing the W to Z ratio (custodial symmetry)

(42)

Main results III : Probing physics beyond the Standard Model

(In the decays and/or in the loops)

Also direct invisible only search

(43)

Main results IV : Other Relevant Models

-  Illustrating the mass dependence

-  3 coupling strength parameter fits κu, κd and κV for MSSM and 2HDM limits

(44)

Cornering (directly) the top Yukawa coupling

Analysis strategy

-  2 channels t(lvb)t(qqb)H(bb) and t(lvb)t(lvb)H(bb) -  Challenging tt+jets background…

-  tt+jets and tt+HF tamed

ttH (bb)

W

W b

b

q b q

b

l ν t

t

ATLAS-‐CONF-‐2014-‐011

(45)

Cornering (directly) the top Yukawa coupling

+light t t

c +c t t

b +b t t

+V t t

W+jets

Z+jets Diboson

Single top Multijet

4 j, 2 b

+light t t

c +c t t

b +b t t

+V t t

W+jets Z+jets

Diboson Single top

Multijet

4 j, 3 b

+light t t

c +c t t

b +b t t

+V t t

W+jets

Z+jets Diboson

Single top Multijet

≥ 4 b

4 j, ATLAS

Preliminary Simulation

= 125 GeV mH

= 8 TeV s

+light t t

c +c t t

b +b t t

+V t t

W+jets Z+jets

Diboson Single top

Multijet

5 j, 2 b

+light t t

c +c t t

b +b t t

+V t t

W+jets Z+jets

Diboson Single top

Multijet

5 j, 3 b

+light t t c

+c t t

b +b t t

+V t t

W+jets Z+jets

Diboson Single top

Multijet

≥ 4 b

5 j, ^t^t^+light

c +c t t

b +b t t

+V t t W+jets Z+jets Diboson Single top Multijet

+light t t

c +c t t

b +b t t

+V t t W+jets Z+jets Diboson Single top Multijet

+light t t

c +c t t

b +b t t

+V t t

W+jets Z+jets

Diboson Single top

Multijet

6 j, 2 b

≥

+light t t

c +c t t

b +b t t

+V t t

W+jets Z+jetsDiboson

Single top Multijet

6 j, 3 b

≥

+light t t c

+c t t

b +b t t

+V t t

W+jets Z+jets Diboson

Single top Multijet

≥ 4 b 6 j,

≥

Single lepton

Analysis strategy

-  2 channels t(lvb)t(qqb)H(bb) and t(lvb)t(lvb)H(bb) -  Challenging tt+jets background…

-  tt+jets and tt+HF tamed

Irreducible not criAcal

13%

ttH (bb)

45

Light rejecAon crucial

ATLAS-‐CONF-‐2014-‐011

II.- Exploring New Era of Higgs Physics