MSSM Higgs searches at the LHC - umich.edumctp/SciPrgPgs/events/2010/Higgs...Bruno Lenzi - CEA...

MSSM Higgs searches at the LHC

Bruno LenziCEA - SaclayOn behalf of ATLAS and CMS collaborations

1

MCTP Spring Symposium on Higgs Boson PhysicsAnn Arbor, Michigan, USA

May 14th 2010

Bruno Lenzi - CEA Saclay MSSM Higgs searches at LHC MCTP Spring 2010

Outline

• Introduction

• LHC, ATLAS and CMS

• The MSSM Higgs sector

• Neutral Higgs boson searches

• Charged Higgs boson searches

• Conclusions

2

Results for , from (unless indicated otherwise):

• Expected Performance of the ATLAS Experiment, Detector, Trigger and Physics (CERN-OPEN-2008-020)

• CMS Physics Technical Design Report Vol.II (CERN/LHCC 2006-021)

√s = 14TeV


• The LHC is running!

• At 7 TeV, with increasing luminosity

• Experiments taking data

3

LHC, ATLAS and CMS


Outline

ATLAS/CMS Optimal for Higgs Searches

Good, Hermetic Calorimetry: Missing ET Measurement, Jet Reconstruction up to |η| < 4.9.

Powerful Particle Identification

∼ 97% Muon Efficiency, Cleanest Identification∼ 80% Electron Efficiency with Jet Rejection of 105

∼ 80% Photon Efficiency with Jet Rejection of 103

∼ 60% b Tagging Efficiency with Light Jet Rejection of 102 (Good Vertexing)∼ 50% Hadronic τ Efficiency with Jet Rejection of 102

Excellent Electron, Photon and Muon Energy- and pT Resolution

Covered in this TalkBSM Higgs Boson Searches in the MSSM

Measurement of Higgs Boson Properties

Results Based ‘Computing System Commissioning’ Studies (ATLAS)and PTDR Vol.II (CMS)

(Unless Indicated Otherwise)

W.Mader (TU Dresden) Higgs Properties and BSM Higgs Boson Searches at the LHC

LHC, ATLAS and CMS

• Good, hermetic calorimetry

• measurement, jet reconstruction up to |η| < 4.9

• Powerful Particle Identification

• ∼ 97% Muon efficiency, cleanest identification

• ∼ 80% Electron efficiency with jet rejection of 105

• ∼ 80% Photon efficiency with jet rejection of 103

• ∼ 60% b-tagging efficiency with light jet rejection of 102

• ∼ 50% hadronic τ efficiency with jet rejection of 102

• Excellent Electron, Photon and Muon energy / Pt resolution

4

Outline

ATLAS/CMS Optimal for Higgs Searches

Good, Hermetic Calorimetry: Missing ET Measurement, Jet Reconstruction up to |η| < 4.9.

Powerful Particle Identification

∼ 97% Muon Efficiency, Cleanest Identification∼ 80% Electron Efficiency with Jet Rejection of 105

∼ 80% Photon Efficiency with Jet Rejection of 103

∼ 60% b Tagging Efficiency with Light Jet Rejection of 102 (Good Vertexing)∼ 50% Hadronic τ Efficiency with Jet Rejection of 102

Excellent Electron, Photon and Muon Energy- and pT Resolution

Covered in this TalkBSM Higgs Boson Searches in the MSSM

Measurement of Higgs Boson Properties

Results Based ‘Computing System Commissioning’ Studies (ATLAS)and PTDR Vol.II (CMS)

(Unless Indicated Otherwise)

W.Mader (TU Dresden) Higgs Properties and BSM Higgs Boson Searches at the LHC

EmissT


MSSM Higgs sector

• Two Higgs doublets, five physical states

• three neutral: h, A and H

• two charged: H±

• Two parameters at tree level

• Mass of the CP-odd boson: mA

• Ratio of the v.e.v.s: tan β

• Large loop corrections

• mh < mZ becomes mh ≲ 130 GeV

• Fixed in benchmark scenarios (mh-max used in most of the results)

• Masses

• Couplings (for large tan β)

• W / Z suppressed, absent for A

• Enhanced with respect to SM for 3rd generation and down type fermions

• h is SM-like for large mA

5

Carena, Heinemeyer, Wagner, WeigleinEur. Phys. J. C26 (2003) pp. 601-7


Neutral Higgs bosons: production and decays

• Production

• Decay modes (typical values for the interesting regions of the parameter space)

• bb with BR ~ 90%

• τ+τ- with BR ~10%

• μ+ μ- with BR ~ 0.03%

• SUSY particles if allowed

• Mass degeneracy

• Of at least two of them in most of parameter space

• Handled by summing cross sections for searches

6

g

g

φ

g

g

b

φ

b̄

b

b̄

φ

b

g

φ

b

g

q

q̄

b

φ

b̄

(φ = h, H, A)Gluon fusion b-quark associated production: dominant at large tan β

Overwhelmed by QCD backgrounds

Possibilities in leptonic and hadronic final states

Clean signature, excellent mass resolution, low yield

Depends strongly on additional parameters


Neutral Higgs searches:

• Motivation

• Clean signal with excellent mass resolution (3% against 20% for ττ)

• Potential to distinguish between h, H and A and provide measurement of tan β (from width)

• Sensitivity for both gluon fusion (ATLAS) and b-associated production (ATLAS / CMS)

• Drawback: small BR (enhanced for high tan β)

• Backgrounds

• Dominant: Drell-Yan Z ( + jets)

•

• WW / ZZ very small

• Can be estimated from data using

7

h/H/A→ µ+µ−

ATLAS / CMS

tt̄→ bb̄µ+µ−νν̄

µ+µ−, e+e−, e±µ∓

Mean 4±Sigma 4.8e−03± 6.3

(GeV)−µ+µm

100 150 200 250 300 350 400

En

trie

s

0

100

200

300

400

500

600

700

800

900 ATLAS

Mean 4e−03± 199.6 Sigma ±

µµbbA −>

= 200 GeVAm

) = 30βtan(

Mean 5e−03± 199.6 Sigma 5.5e−03± 6.3

(GeV)−µ+µm

100 150 200 250 300 350 400

En

trie

s

0

100

200

300

400

500

600

700

800

Mean ±Sigma ±

µµgg−> A −>

= 200 GeVAm

) = 30βtan(

ATLAS

[GeV]ττm0 50 100 150 200 250 300

Arbi

trary

Uni

ts

0

(130 GeV)ττ→H

Gaussian fit

= 24.6 GeVσ

= 119.4 GeVµ

ATLAS


(GeV)missTE

0 50 100 150 200310×

Nor

mal

ized

to u

nity

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35 = 200 GeV

AbbA, mZ+light jetsZ+ b jetsttZZWW

ATLAS


• Event selection

• Trigger on single-mu or di-muons (> 90% efficiency)

• High-Pt isolated muon(s) (20 GeV)

• Background reduction

• Cuts on , jet activity and angle between muons to reject tt and WW

• B-tagging requirements

• ATLAS: two independent optimizations

• 0 b-jet, dominated by Z + jets

• ≥1 b-jets, with important contribution from tt

• CMS:

• Two different strategies to increase efficiency for high and low-Pt b-jets

8

h/H/A→ µ+µ−

ATLAS / CMS

EmissT

0 b-tagged jet ≥ 1 b-tagged jets

(GeV)µµm150 200 250 300 350

310×

Entr

ies

/ (4

GeV

)

1

10

210

310

410

510

150 200 250 300 350

310×1

10

210

310

410

510

bbA Z+l jets

Z+b jets

WW tt

ZZ

=150 GeVAm

=200 GeVAm

=300 GeVAm

a)ATLAS

(GeV)µµm150 200 250 300 350

310×

Entr

ies

/ (4

GeV

)

1

10

210

310

410

510

150 200 250 300 350

310×1

10

210

310

410

510 bbA Z+l jets

Z+b jets

WW tt

ZZ

=150 GeVAm

=200 GeVAm

=300 GeVAm

b)ATLAS

L = 30 fb-1


)2 (GeV/cAM160 180 200 220 240

)2 (GeV/cAM160 180 200 220 240

βta

n

20

30

40

50

60

-1CMS, 30 fb

scenariomaxhm

2 = 1 TeV/cSUSYM2 = 200 GeV/c2M

2 = 200 GeV/cµ2 = 800 GeV/cgluinom

SUSY = 2 MtStop mix: X

100 150 200 250 300 350 400

10

20

30

40

50

100 150 200 250 300 350 400

10

20

30

40

50

)2 (GeV/cAM100 150 200 250 300 350 400

βta

n

10

20

30

40

50

-1CMS, 30 fb

2 = 1 TeV/cSUSYM2 = 200 GeV/cµ

2 = 200 GeV/c2M

SUSY M6 = tX


• Discovery potential

• Low to intermediate masses for tan β > 20

• Sensitivity to tan β from mμμ peak width

• Systematic uncertainties

• Theoretical (~ 17%)

• Experimental (5 - 12%)

• Muon reconstruction efficiency, momentum scale and resolution

• Jet energy scale and resolution

• b-tagging efficiency and fake rate

9

h/H/A→ µ+µ−

ATLAS / CMS

(GeV) (GeV)AAmm5050 100100 150150 200200 250250 300300 350350 400400 450450

dis

cove

ry d

isco

very

σβ

σβ

tan

f

or

5

0

1010

2020

3030

4040

5050

6060

−1L=10 fb

maxh

−1

Combined AnalysisCombined Analysis

m − scenario

Without SystematicsWithout Systematics

L=30 fb

With Experimental SystematicsWith Experimental Systematics

Theoretical UncertaintyTheoretical Uncertainty

ATLAS

discovery contour discovery contourσσ55

tan β measurement for tan β = 30, 40, 50Discovery contour

(dashed line: no systematics)



• Final states (tau decay products)

• Leptons, leptons (ATLAS / CMS)

• Leptons, hadrons (CMS, ATLAS to appear)

• Hadrons, hadrons (CMS)

• Backgrounds

•

• QCD multi-jets in hadronic case

• + jets for leptonic decay


• tau fake rates

• Jet energy scale / resolution and

• b-tagging efficiency and purity

• Tau identification

• Hadronic:

• 1 or 3 tracks,

• Isolation in tracker

• 50% efficiency with jet rejection > 100

• Leptonic:

• High-Pt isolated lepton

• mττ using collinear approximation

• Background reduction

• One or more b-tagged jets

• Jet activity (tt, W + jets), di-lepton mass (Z)

• CMS: lepton impact parameter,

10

Z → e+e−/µ+µ−

Z → τ+τ−, tt̄, W + jets

EmissT

(bb̄)h/H/A→ ττ

P leadingT = 10, 20GeV

mT (�, EmissT )


[GeV]ττm0 50 100 150 200 250 300

Cro

ss S

ectio

n (fb

/ 15

GeV

)

05

10152025303540

[GeV]ττm0 50 100 150 200 250 300

Cro

ss S

ectio

n (fb

/ 15

GeV

)

05

10152025303540

=130 GeVAm=20βtan

→ ← ττ→Hττ→Zµµ→Z

ee→ZttbarW+jets

ATLAS


• Motivation

• Leptons to trigger on

• Lower backgrounds

• Z + jets and tt mainly

• Event selection

• ATLAS: Cut on di-lepton mass against

• CMS: Displaced lepton impact parameters

• Jet veto against tt

• One or more b-tagged jets (analysis with no b-tagging for early data)

11

(bb̄) h/H/A→ ττ → 2�4ν

ATLAS ( ) / CMS ( )eµ

Z → e+e−/µ+µ−

2�

)2 (GeV/cττm0 50 100 150 200250 300 350400 450 500

-1 for

30 fb

2E

vents

/25 G

eV

/c

0

5

10

15

20

25

30

35

40

45 CMS

+Xµe→ττ→H/A

-max scenariohm2 = 200 GeV/cAm

= 25βtanSignal

*γZ/

tt

Backgr

(b)


/ GeVAm150 200 250 300 350 400 450

βta

n

0

10

20

30

40

50

60

Exp. Systematics only

(tt) Uncertaintyσ+10%

Theoretical Uncertainty

ATLAS -1=14 TeV, 30 fbs

scenariomaxhm

ν 2 l + 4 →ττ→bb h/H/A

Discoveryσ5



• Best at low masses

• Decreases quickly with mass

• High tan β needed


• shape and normalization from data

• tt yields

• Jet energy scale and resolution

• b-tagging efficiency

12

(bb̄) h/H/A→ ττ → 2�4ν

Z → τ+τ−

)2(GeV/cm100 150 200 250 300 350 400 450 500

!tan

10

20

30

40

50

Excluded by LEPExcluded by LEP

Full simulationsystematic uncertainties

Excluded by LEP

-1CMS, 30 fb

2 = 200 GeV/c2

, M2 = 200 GeV/Cµ

2 = 1 TeV/cSUSY

, M2 = 2 TeV/ctA

Full simulation, with

Fast simulation

+Xµe"##"H/A

Figure 25: The 5 -discovery reach for heavy neutral Higgs bosons H and A decaying via to e+ final state.The dots give the 5 limit for the studied values of Higgs mass. The fast simulation result is also shown.

simulation results [5] are shown for comparison. The main difference comes from updated signal and backgroundcross sections and worse than expected MET and mass resolution with more background events in the mass win-dow. The cuts are, however, more optimized. The uppermost curve shows the discovery region with the effect ofthe systematic background uncertainty taken into account. The systematic uncertainties decrease the explorableregion.

N +N N Significance(meas.) (MC) = 0% 12%

m = 140 GeV/ , tan = 20 100 - 200 GeV/ 225 107 9.9 7.3m = 200 GeV/ , tan = 20 140 - 250 GeV/ 163 109 4.8 3.1m = 250 GeV/ , tan = 20 160 - 380 GeV/ 244 204 2.7 1.4

Table 5: Number of measured events in given mass windows and estimated number of background events for30 fb and statistical significance calculated with Poisson statistics.

8 ConclusionsThe Higgs boson discovery potential in channel with Higgs boson produced in associationwith two b quarks is studied with full simulation. The tagging of one associated b jet is used to suppress the back-grounds. The Higgs boson mass is reconstructed exploiting the collinear neutrino approximation. The 5 coverageis updated and the effect of systematic errors included. The systematic uncertainties decrease the discovery reach.The largest component in the systematic errors is the uncertainty of the calorimeter energy scale.

The best strategy to improve these results is to improve the MET measurement. The mass resolution dependsstrongly on the quality of the MET measurement. Smaller width of the mass peak would decrease the number ofbackground events within the mass window. It would also allow separating the Higgs mass peak from the Z peak,and make fitting the signal and background a realistic possibility. The mass width can, however, be improved byselecting events with harder b jets as it results in better defined MET. The signal, for which the associated jets aresoft, would be suppressed though, and optimization gives better results for low jet cut. For the same reason nostrong cut is used, although improving the mass resolution that way is possible.

The optimization of b tagging gave best results with very loose discriminator cuts. Despite the potential newbackgrounds, this is hinting that a Higgs search strategy with no b tagging may be possible. If events with noassociated jets are selected, the background is efficiently suppressed while the is enhanced. The signalwould consist of Higgs bosons produced via loop mediated gluon fusion in addition to associated production

with no successfully reconstructed jets. This approach remains yet to be studied.

14

(modified Z → µ+µ−)


)2 (GeV/cττm0 100 200 300 400 500 600 700 800

-1 fo

r 30

fb2

Eve

nts/

25 G

eV/c

0

10

20

30

40

50CMS

-jet + Xτe+→ττ→H/A2 = 200 GeV/cAm

= 20βtan

2 = 1 TeV/cSUSY

, M2 = 2 TeV/ctX

2 = 200 GeV/c2

, M2 = 200 GeV/Cµ

ee→*γZ/

Signal

Backgr


13

(bb̄)h/H/A→ ττ → (e/µ) had

CMS

e + jets

μ + jets

• Motivation

• Good BR and lepton for trigger

• Backgrounds

• tt, single top, Z + jets, W + jets, QCD


• b-tagging, jet energy scale, lepton ID


• Low to intermediate masses at relatively low tan β

• Challenging for high masses

]2 [GeV/cτ τm0 200 400 600 800 1000

]2/ 2

0 [G

eV/c

-1E

vent

s fo

r 20

fb

0

10

20

30

40

50

60

70 Background)=20,βSignal+Bkg. for tan(

2=200 GeV/cAm)=30,βSignal+Bkg. for tan(

2=500 GeV/cAm



• Motivation

• Good BR and lepton for trigger

• Backgrounds

• tt, single top, Z + jets, W + jets, QCD


• b-tagging, jet energy scale, lepton ID


• Low to intermediate masses at relatively low tan β

• Challenging for high masses

14

(bb̄)h/H/A→ ττ → (e/µ) had

CMS

MSSM Higgs Boson Searches Neutral MSSM Higgs Bosons h/H/A

bbh/H/A, h/H/A → τ(lep)τ(had) (CMS)Discovery Potential

e + jets µ + jets

� good for intermediate to low mass range� (ATLAS analysis in preparation)� at high masses higher sensitivity in the fully hadronic channel

Jan Schumacher (TU Dresden) BSM Higgs Boson Searches at the LHC WIN09 9 / 23

e + jets

μ + jets

]2 [GeV/cAm

200 250 300 350 400 450 500 550 600

)βta

n(

10

20

30

40

50

60

Discovery area -1for 30 fb

H max m 2 = 1000 GeV/cSUSY m 2 = 2449 GeV/cMS

t X 2 = 200 GeV/cµ 2 = 200 GeV/c2 M



• Motivation:

• High BR ( not feasible)

• Sensitivity for high masses

• Main background: QCD multi-jets

• Estimated from data using same sign “tau’s”


• Jet energy scale / resolution

• τ fake rate from tracker misalignment

15

(bb̄)h/H/A→ ττ → had had

CMS


bbh/H/A, h/H/A → τ(had)τ(had) (CMS)� Motivation

� high hadronic branching ratio� dominant h/H/A→ bb overwhelmed by QCD� τ tagging makes channel feasible� sensitivity for high masses

� Event Selection� hadronic final state, need good τ -trigger� τ identification

� isolation in tracker

� 1 or 3 tracks, hard leading track

(pt > 50GeV)

� ≈ 50% efficiency at a rejection of 100

� exactly one b-tagged jet

� Backgrounds and Systematics� QCD jets: shape from data-driven method

using signal free same-sign τs� uncertainty of τ fake rate due to

tracker misalignment� E

missT scale uncertainty 2,GeV/cAM

100 200 300 400 500 600 700 800

!tan

10

20

30

40

50

-1CMS, 30 fb = h,H,A", " bb#pp

scenariomaxhm




µ e

# $$ # "

+jet

µ # $$

# "

e+jet# $$ # "

-1

jet+jet, 60 fb

# $$ # "

µµ

# "


bb̄

2,GeV/cAM100 200 300 400 500 600 700 800

βtan

10

20

30

40

50

-1CMS, 30 fb = h,H,Aφ, φ bb→pp

scenariomaxhm




µ e

→ ττ → φ

+jet

µ → ττ

→ φ

e+jet→ ττ → φ

-1

jet+jet, 60 fb

→ ττ → φ

µµ

→ φ



A/H → χ̃02χ̃

02 → 4� + E

missT

� Analysis� MSSM / mSUGRA points optimized for

lepton BR

� Backgrounds and Event Selection� 4 leptons, opposite signs and flavours� tt̄: jet multiplicity� ZZ , Zbb: Emiss

T lower bound,dilepton masses

� SUSY, EmissT upper bound, jet multiplicity

� Systematic Uncertainties� little experimental uncertainty� strongly model dependent


• Scenarios:

• MSSM / mSugra points favoring decays to leptons

• Backgrounds: tt, ZZ, Zbb, SUSY

• Event selection:

• 4-leptons with opposite signs and flavors

• Upper and lower bounds on

• Cuts on di-lepton mass and jet multiplicity


• Small from experimental side

• Strongly model dependent


16


A/H → χ̃02χ̃

02 → 4� + E

missT

� Analysis� MSSM / mSUGRA points optimized for

lepton BR

� Backgrounds and Event Selection� 4 leptons, opposite signs and flavours� tt̄: jet multiplicity� ZZ , Zbb: Emiss

T lower bound,dilepton masses

� SUSY, EmissT upper bound, jet multiplicity

� Systematic Uncertainties� little experimental uncertainty� strongly model dependent


H/A→ χ̃02χ̃

02 → 4� + E

missT

EmissT

CMS PTDR


MSSM Higgs Boson Searches Charged MSSM Higgs Bosons H±

Charged Higgs Boson H±

Searches

� Motivation

� predicted by two Higgs doublet models

(e.g. MSSM)

� models with Higgs triplets (e.g. little

Higgs)

� smoking gun evidence for physics beyond

the SM

� Low Mass Case mH+ < mt

� production via t → H+b

� decay via H+ → τν

� small tan β: H+ → cs

(ATLAS analysis in preparation)

� High Mass Case mH+ > mt

� production via gg → tbH+

and gb → tH+

� decay via H+ → tb

g

g

g

b

bt

t H +

W−

g

g

b

bt

tb

W−H +


MSSM Higgs Boson Searches Charged MSSM Higgs Bosons H±

Charged Higgs Boson H±

Searches

� Motivation

� predicted by two Higgs doublet models

(e.g. MSSM)

� models with Higgs triplets (e.g. little

Higgs)

� smoking gun evidence for physics beyond

the SM

� Low Mass Case mH+ < mt

� production via t → H+b

� decay via H+ → τν

� small tan β: H+ → cs

(ATLAS analysis in preparation)

� High Mass Case mH+ > mt

� production via gg → tbH+

and gb → tH+

� decay via H+ → tb

g

g

g

b

bt

t H +

W−

g

g

b

bt

tb

W−H +


Charged Higgs boson: production and decays

• Light charged Higgs

• Produced mainly through top decay

• Decays mostly to τν

• Heavy charged Higgs

• Produced mainly by gb or gg

• Decays mostly to tb (or τν)

• Backgrounds

• tt, W + jets, single top, QCD

17

(mH+ < mt)

(mH+ > mt)

!tan0 10 20 30 40 50

b)± H

"B

R(t

-410

-310

-210

-110

1 2=140GeV/c+Hm2=150GeV/c+Hm2=160GeV/c+Hm2=170GeV/c+Hm

(a)


Light charged Higgs boson searches

• Final states:

• τ → hadrons, W → qq (ATLAS) ➝ High yields

• τ →ℓν, W → qq (ATLAS) ➝ Isolated lepton from τ

• τ →hadrons, W →ℓν (ATLAS / CMS) ➝ Isolated lepton from W

• Backgrounds

• tt, W + jets, QCD, single top

• Common features

• Presence of tau, large , b and light jets

• ATLAS: H+ transverse mass reconstruction


• tt cross section, estimated from data (ATLAS)

• b / τ-tagging efficiencies and fake rates

• Jet energy scale

18

(mH+ < mt)

EmissT

Top Transverse Momentum [GeV] 0 50 100 150 200 250 300 350 400

Arb

itra

ry U

nits

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

ATLAS

bjjντ b→tReal t

bjjντ b→tScaled t

tt̄ estimation from µνbµνb


Light charged Higgs boson searches

• τ → hadrons, W → qq (ATLAS)

• Trigger on tau + ( + jets)

• τ-jet, 2 b-tagged jets, at least 2 more

• Veto on isolated lepton, tt reduced with likelihood discriminant

• τ →lν, W → qq (ATLAS)

• Trigger on lepton +

• Isolated lepton, at least 4 jets, 2 b-tagged, large

• Hadronic W and top mass reconstruction

• τ →hadrons, W →lν (ATLAS / CMS)

• Trigger on lepton (+ , ATLAS)

• At least 3 jets, 1 b and 1 τ-tagged (or more ATLAS)

• Large , isolated lepton

19

(mH+ < mt)

EmissT

2,GeV/c+H

M90 100 110 120 130 140 150 160 170 180

βta

n

10

20

30

40

50

60

70

80

2 = -1000 GeV/cµ2 = -200 GeV/cµ

2 = 200 GeV/cµ2 = 1000 GeV/cµ

-1CMS, 30 fb νντ → ±, H± tbH→pp 2 = 175 GeV/ctm

scenariomaxhm


SUSY = 0.8 Mgluinom

SUSY = 2 M

tX

(arX

iv:0

804.

1228

v1)

90 100 110 120 130 140 150 160 170

5

10

15

20

25

30

35

40

45

50

55

60

mH+ [GeV]

tanβ

5σ discovery sensitivity

Scenario B ATLAS

30 fb−1

10 fb−1

1 fb−1

τ →

had

rons

, W →

qq

mh-m

ax,μ

= 2

00 G

eV

EmissT

EmissT

EmissT

EmissT


)2) (GeV/cmissT

jet, Eτ(Tm0 50 100 150 200 250 300 350

-1 fo

r 30

fb2

Eve

nts

/ 30

GeV

/c

0

5

10

15

20

25

30

qqb→, t ± tbH→ gg

τν hadrons + → τ, τντ → ± H2 = 170 GeV/c±H m

CMS

signal

total background

Heavy charged Higgs boson searches

• Final states

•

• Similar to light charged Higgs analysis

• CMS: Requires hard tau and jets

• ATLAS: Likelihood discriminant based on tau, jets and

•

• 5 or 6 jets, 3 or 4 b-tagged

• Constraints on W and t mass

• Difficulties from combinatorics, likelihood used (ATLAS)

20

(mH+ > mt)

EmissT

ATLAS / CMS(gg → tbH+ and gb→ tH+)

H+ → tb (W → qq and the otherW → �ν) [GeV]+Hm

0 100 200 300 400 500 600 700 800 900 1000

Cro

ss S

ectio

n [fb

/ 50

GeV

]

0

2

4

6

8

10

12 = 200 GeV+Hm

Signal + Background

+ jetstt (QCD)b btt (ElW)b btt

ATLAS

[GeV]+Hm0 100 200 300 400 500 600 700 800 900 1000

Cro

ss S

ectio

n [fb

/ 50

GeV

]

0

2

4

6

8

10

12 = 250 GeV+Hm

Signal + Background

+ jetstt (QCD)b btt (ElW)b btt

ATLAS

[GeV]+Hm0 100 200 300 400 500 600 700 800 900 1000

Cro

ss S

ectio

n [fb

/ 10

0 G

eV]

0

2

4

6

8

10

12 = 400 GeV+Hm

Signal + Background + jetstt

(QCD)b btt (ElW)b btt

ATLAS

[GeV]+Hm0 100 200 300 400 500 600 700 800 900 1000

Cro

ss S

ectio

n [fb

/ 10

0 G

eV]

0

2

4

6

8

10

12 = 600 GeV+Hm

Signal + Background + jetstt

(QCD)b btt (ElW)b btt

ATLAS

H+ → τν (W → qq, τ → hadrons)


Heavy charged Higgs boson searches

21

(mH+ > mt)

ATLAS / CMS

mH+ [GeV]

tanβ


ATLASScenario B

200 250 300 350 400 450 500 550 600

5

10

15

20

25

30

35

40

45

50

55

60

30 fb−1

10 fb−1

1 fb−1

• Final states

•

• Similar to light charged Higgs analysis

• CMS: Requires hard tau and jets

• ATLAS: Likelihood discriminant based on tau, jets and

•

• 5 or 6 jets, 3 or 4 b-tagged

• Constraints on W and t mass

• Difficulties from combinatorics, likelihood used (ATLAS)

EmissT

(gg → tbH+ and gb→ tH+)

H+ → tb (W → qq and the otherW → �ν)

H+ → τν (W → qq, τ → hadrons)


Charged Higgs boson expected discovery potential

• Good sensitivity at low masses and/or high tan β, dominated by

• Difficult in intermediate tan β

• Decays to SUSY particles might be an alternative

22

H+ → τν

2,GeV/cAM100 200 300 400 500 600

βta

n

10

20

30

40

50

60

70

80

2 = -1000 GeV/cµ2 = -200 GeV/cµ

2 = 200 GeV/cµ2 = 1000 GeV/cµ

scenariomaxhm

2 = 1 TeV/cSUSY

M2 = 200 GeV/c2M

SUSY = 0.8 Mgluinom

SUSY = 2 MtX

mH+ [GeV]ta

nβ


ATLASScenario B

90 110 130 150 170 200 250 400 600

5

10

15

20

25

30

35

40

45

50

55

60

30 fb−1

10 fb−1

1 fb−1

CDF Run IIExcluded95% CL

mh-max,μ = 200 GeV, Δb effects includedCMS, L = 30 fb-1 (arXiv:0804.1228v1)(black lines include Δb effects)


Conclusions

• Good discovery potential for MSSM Higgs at LHC

• At least one Higgs boson will be found if present

• Large regions of parameter space can be covered, some need high statistics

• Neutral Higgs boson

• Sensitivity dominated by , coverage up to mA ~ 800 GeV

• helps at low masses and gives narrow peak

• Charged Higgs boson

• Good sensitivity at low masses and high tan β with

23

h/H/A→ τ+τ−

h/H/A→ µ+µ−

H+ → τν

Backup slides

24

Bruno Lenzi - CEA Saclay MSSM Higgs searches at LHC MCTP Spring 2010 25

Point m0 (GeV/c2)

m1/2 (GeV/c2)

A0 (GeV/c2)

tanβ sign(μ)

CMS A

CMS B

CMS C

ATLAS A

ATLAS B

60 175 0 10 +

80 200 0 5 +

50 150 0 5 +

400 165 0 20 +

125 165 0 20 +

MSSM scenarios studied

Scenario OBS mt (GeV) MSUSY (GeV)

μ (GeV)

M2, M3 (GeV) At

A

B

H+ to SUSY suppressed 175 500 200 1000 1000

mh-max 170 1000 200 200, 800

Xt(2000) + μ/tan β

ATLAS, charged Higgs

Neutral Higgs to SUSY particles, mSUGRA

Set M1 (GeV) M2 (GeV) μ (GeV)

msl, mstau (GeV)

msg, msq (GeV)

1

2

90 180 -500 250 1000

100 200 -200 150, 250 800, 1000

Neutral Higgs to SUSY particles, MSSM (ATLAS)

• MSUSY : soft-SUSY breaking mass

• μ: Higgsino mixing parameter

• m1/2, M1, M2: gaugino masses

• M3: gluino mass

• m0: scalar masses

• A0: trilinear coupling

• mtXt: off-diagonal entry in stop mass matrix

Date post:	27-Mar-2021
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MSSM Higgs searches at the LHC - umich.edumctp/SciPrgPgs/events/2010/Higgs...Bruno Lenzi - CEA...

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