(SUSY) Higgs Search at the LHC
Milada Margarete Muhlleitner
(LAPTH)
SUSY2008
The 16th International Conference on Supersymmetry and
the Unification of Fundamental Interactions
June 16-21, 2008, COEX, Seoul, Korea
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
SM Higgs Sector - Mass Constraints
• Triviality → upper bound
Vacuum stability → lower bound
Cabibbo,...;Sher;Lindner;Hasenfratz,...;Luscher, Weisz;Hambye,...;...
Hambye,Riesselmann
Λ = 1 TeV : 55 GeV <∼ MH <
∼ 700 GeV
ΛGUT = 1016 GeV: 130 GeV <∼ MH <
∼ 190 GeV
• Fits to electroweak precision data LEP Coll.
0
1
2
3
4
5
6
10030 300
mH [GeV]
∆χ2
Excluded Preliminary
∆αhad =∆α(5)
0.02758±0.00035
0.02749±0.00012
incl. low Q2 data
Theory uncertaintyMarch 2008 mLimit = 160 GeV
EWWG
MH = 87+36−27 GeV, MH <
∼ 190 GeV @ 95% CL
• Direct search @ LEP: [MH = 115.3 GeV]
���
�����
���
� � � �
� �������
MH > 114.4 GeV @ 95% CL LEP Coll.
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Higgs Boson Search at the LHCSpira
σ(pp→H+X) [pb]√s = 14 TeVMt = 174 GeVCTEQ6M
gg→H
qq→Hqqqq_’→HW
qq_→HZ
gg,qq_→Htt
_
MH [GeV]0 200 400 600 800 1000
10-4
10-3
10-2
10-1
1
10
10 2
0 200 400 600 800 1000
• gg fusion dominant, second largest vector boson fusion
• MH <∼ 140 GeV: H → γγ, (bb)
• 140 GeV <∼ MH <
∼ 1 TeV: H → ZZ(∗) → 4l± (gold plated), H →WW, ZZ → l’s, jets
• 120 GeV <∼ MH <
∼ 200 GeV: H →WW (∗) → l+l−νν (ang. corr.) Dittmar,Dreiner
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Higgs Boson Search Reach at the LHC
ATLAS CMS
1
10
10 2
102
103
mH (GeV/c2)
Sig
nal s
igni
fica
nce
H → γ γ ttH (H → bb) H → ZZ(*) → 4 l H → WW(*) → lνlν qqH → qq WW(*) → lνlν qqH → qq ττ qqH → qqZZ → llνν qqH → qqWW → lνjj
Total significance
5 σ
∫ L dt = 30 fb-1
(no K-factors)
ATLAS
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
T he MSSM Higgs Sector
MSSM Higgs sector – supersymmetry & anomaly free theory ⇒ 2 complex Higgs doublets
neutral, CP-even h, H neutral, CP-odd A charged H+, H−EWSB→
Higgs masses
Mh <∼ 140 GeV
MA,H,H± ∼ O(v)...1 TeV
Ellis et al;Okada et al;Haber,Hempfling;Hoang et al;Carena et al;Heinemeyer et al;Zhang et al;Brignole et al;...
Decoupling limit:
MA ∼MH ∼MH± � v
Mh → max. value, tanβ fixed; h becomes SM-like
Modified couplings with respect to the SM: (decoupling limit Gunion,Haber)
Φ gΦuu gφdd gΦV V
h cα/sβ→ 1 −sα/cβ→ 1 sβ−α→ 1
H sα/sβ→ 1/tgβ cα/cβ→ tgβ cβ−α→ 0
A 1/tgβ tgβ 0
tanβ ↑ ⇒ gΦuu ↓
gΦdd ↑
gMSSMΦV V
<∼ gSM
ΦV V
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
MSSM Higgs Boson Production at the LHC
Spiraσ(pp→h/H+X) [pb]√s = 14 TeVMt = 174 GeVCTEQ6M
Mh/H [GeV]
tgβ = 3gg→H
Hbb_
Htt_
Hqq
HZ HW
gg→h
hbb_
htt_hZ
hWhqq
h H❍ ❍100 200 500 1000
10-4
10-3
10-2
10-1
1
10
10 2
10 3
10 4
90100 200 300 400 500 600 700800900
σ(pp→h/H+X) [pb]√s = 14 TeVMt = 174 GeVCTEQ6M
Mh/H [GeV]
tgβ = 30
gg→H
Hbb_
Htt_HZ
HW
Hqq
gg→h
hbb_
htt_hZ
hWhqq
h H❍ ❍100 200 500 1000
10-4
10-3
10-2
10-1
1
10
10 2
10 3
10 4
90100 200 300 400 500 600 700800900
ATLAS CMS
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
MSSM Higgs Boson Production at the LHC
Spiraσ(pp→h/H+X) [pb]√s = 14 TeVMt = 174 GeVCTEQ6M
Mh/H [GeV]
tgβ = 3gg→H
Hbb_
Htt_
Hqq
HZ HW
gg→h
hbb_
htt_hZ
hWhqq
h H❍ ❍100 200 500 1000
10-4
10-3
10-2
10-1
1
10
10 2
10 3
10 4
90100 200 300 400 500 600 700800900
σ(pp→h/H+X) [pb]√s = 14 TeVMt = 174 GeVCTEQ6M
Mh/H [GeV]
tgβ = 30
gg→H
Hbb_
Htt_HZ
HW
Hqq
gg→h
hbb_
htt_hZ
hWhqq
h H❍ ❍100 200 500 1000
10-4
10-3
10-2
10-1
1
10
10 2
10 3
10 4
90100 200 300 400 500 600 700800900
ATLAS CMS
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Higgs Boson Production in gluon gluon fusion
(i) Dominant: Gluon Fusion pp → gg → HSM/ h, H, A (small & moderate tan β)
p
p
g
g
Q,Qh, H
QCD corrections to top & bottom loops
NLO (SM, MSSM): increase σ by ∼ 10...100% Spira,Djouadi,Graudenz,ZerwasDawson;Kauffman,Schaffer
[moderate for large tanβ ← b-loop]
SM; tgβ <∼ 5: limit MΦ � mt - approximation ∼ 20-30% Kramer,Laenen,Spira
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
gg→ H at NLO
Spira,Djouadi,Graudenz,Zerwas
K(pp→H+X)√s = 14 TeV
µ = M = MHMt = 175 GeVCTEQ4
Ktot
Kgg
KvirtKqq
Kgq
MH [GeV]50 100 200 500 1000
-0.5
0
0.5
1
1.5
2
2.5
3
10 2 10 3
σ(pp→H+X) [pb]√s = 14 TeV
µ = M = ξ MH
Mt = 175 GeVMH = 150 GeVCTEQ4
NLO
LO
ξ
5
7
10
20
30
50
σ(pp→H+X) [pb]√s = 14 TeV
µ = M = ξ MHMt = 175 GeVMH = 500 GeVCTEQ4
NLO
LO
ξ
1
2
3
5
7
10
6789
10
20
30
40
0 0.5 1 1.5 2 2.5 3 3.5 4
1
2
3
4
56789
10
0 0.5 1 1.5 2 2.5 3 3.5 4
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Higgs Boson Production in gluon gluon fusion
QCD corrections to top & bottom loops
NLO (SM, MSSM): increase σ by ∼ 10...100% Spira,Djouadi,Graudenz,ZerwasDawson;Kauffman,Schaffer
SM; tgβ <∼ 5: limit MΦ � mt - approximation ∼ 20-30% Kramer,Laenen,Spira
NNLO @ MΦ � mt ⇒ further increase by 20-30%Harlander,KilgoreAnastasiou,MelnikovRavindran,Smith,van Neervenscale dependence: ∆ <
∼ 10− 15%
mt effect on high-energy NNLO K-factor Marzani et al.
Estimate of NNNLO effects improved perturbative convergence Moch,VogtRavindran
Soft gluon resummation: + ∼ 10% Catani,de Florian,Grazzini,Nason
EW 2-loop effects ∼ 5− 8% increase Aglietti et al.;Degrassi,Maltoni
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
gg→ H at NNLO and beyond
Harlander,Kilgore
10-3
10-2
10-1
1
100 120 140 160 180 200 220 240 260 280 300
σ(pp →H+X) [pb]
MH [GeV]
LONLONNLO
√s = 2 TeV
Moch,Vogt
0
0.5
1
1.5
2
100 120 140 160 180 200MH(GeV)
σ(pp → H+X) [pb]
NLO
N2LO
N3LOapprox.
+ N3LL
√s = 2 TeV
LO
MH(GeV)
σ(pp → H+X) [pb]
NLO
N2LO
N3LOapprox.
+ N3LL
√s = 14 TeV
LO
0
20
40
60
80
100 150 200 250 300
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Higgs Boson Production in gluon gluon fusion
QCD corrections to top & bottom loops
NLO (SM, MSSM): increase σ by ∼ 10...100% Spira,Djouadi,Graudenz,ZerwasDawson;Kauffman,Schaffer
SM; tgβ <∼ 5: limit MΦ � mt - approximation ∼ 20-30% Kramer,Laenen,Spira
NNLO @ MΦ � mt ⇒ further increase by 20-30%Harlander,KilgoreAnastasiou,MelnikovRavindran,Smith,van Neervenscale dependence: ∆ <
∼ 10− 15%
mt effect on high-energy NNLO K-factor Marzani et al.
Estimate of NNNLO effects improved perturbative convergence Moch,VogtRavindran
Soft gluon resummation: + ∼ 10% Catani,de Florian,Grazzini,Nason
EW 2-loop effects ∼ 5− 8% increase Aglietti et al.;Degrassi,Maltoni
NLO corrections: to squark loops in heavy squark limit Dawson,Djouadi,Spira
full SUSY-QCD corrections in heavy mass limit Harlander,Steinhauser;Harlander,Hofmann;Degrassi,Slavich
mQ<∼ 400 GeV: NLO squark mass effects ∼ 15% Anastasiou,Beerli,Bucherer,Daleo,Kunszt;
Aglietti,Bonciani,Degrassi,Vicini; MMM,Spira
full NLO SUSY QCD calculation Anastasiou,Beerli,Daleo;MMM,Rzehak,Spira
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
σNLO w/ full squark mass dependence / σNLO in the heavy squark limit
MMM,Spira
√s = 14 TeVtgβ = 3
σ(pp → h/H + X) / σ∞
mt = 174.3 GeVCTEQ6
Mh/H [GeV]
h H❍ ❍
80 100 200 300 500 700 10000.92
0.94
0.96
0.98
1
1.02
1.04
80 90100 200 300 400 500 600 7008009001000
√s = 14 TeVtgβ = 30
σ(pp → h/H + X) / σ∞
mt = 174.3 GeVCTEQ6
Mh/H [GeV]
h H❍ ❍80 100 200 300 500 700 1000
0.75
0.8
0.85
0.9
0.95
1
1.05
1.1
1.15
1.2
80 90100 200 300 400 500 600 7008009001000
no g loops, but bulk of expected SUSY QCD corrections
σ(pp→ h/H + X)/σ∞ up to 20%
Kinks, bumps, spikes: t1¯t1, b1
¯b1, b2
¯b2 thresholds in consecutive order with rising Higgs mass.
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Higgs Boson Production in W/Z boson fusion
(ii) W/Z boson fusion: pp → qq → qq + WW/ZZ → qq + HSM/ h, H
W, Z H, h
q
qCahn,DawsonHikasaAltarelli,Mele,Pitolli
Contribution to H → γγ discovery contour; MSSM: h, H → τ+τ−Plehn,Rainwater,Zeppenfeld
Important role in Higgs coupling determination at the LHC Duhrssen et al.Hankele,Klamke,Zeppenfeld,Figy
Typical signature: 2 hard jets with large rapidity interval and no hadronic activity between them
NLO QCD corrections to total rate (SM/MSSM) ∼ 5 to 10% Han,Valencia,Willenbrock
distributions (SM/MSSM) ∼ 20 % Figy,Oleari,ZeppenfeldBerger,Campbell
dominant NLO QCD to H+3j Figy,Hankele,Zeppenfeld
Full EW & QCD corrections ∼ 5% Ciccolini,Denner,Dittmaier ∆theor ∼ 5 %
SUSY QCD corrections small Djouadi,Spira
SUSY EW+QCD corrections small Hollik,Plehn,Rauch,Rzehak
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Associated production with a bb pair
(iii) Higgs bb production: dominant MSSM Higgs production mechanism for tanβ >∼ 7
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Associated production with a bb pair
• Four-flavour scheme: LO cxn gg → bbΦ0
g
b
b
Φ0
q
q
logQ2
m2
b
g
g
b
b
Φ0
dominant
Q ∼ ( 110 ... 14 )MΦ
NLO with 0,1,2 high-transverse momentum b jets Dittmaier,Kramer,Spira,Walser;Dawson,Jackson,Reina,Wackeroth
large logs from phase space integration absorbed in bottom PDF
• Five-flavour scheme: LO cxn bb → Φ0
Φ0
b
b
NNLO
g
b
b
Φ0
NLO
Dicus,WillenbrockStelzer et al.;Balazs et al.Campbell et al.Harlander,KilgoreKidonakis
• Detailed comparisons: similar results√
Campbell et al.
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Comparison 4- and 5-flavor scheme
Campbell et al.;Harlander,Kilgore
σ(pp → bb_
h + X) [fb]
√s = 14 TeVµ = (2mb + Mh)/4
Mh [GeV]
bb_
→ h (NNLO)
gg → bb_
h (NLO)10
10 2
10 3
100 150 200 250 300 350 400
σ(pp → b/b_
+h + X) [fb]√s = 14 TeV
|ηb/b_ | < 2.5
µ = (2mb + Mh)/4pTb/b
_ > 20 GeV
gg → bb_
+hgb/b
_ → b/b
_ +h
Mh [GeV]
1
10
10 2
100 150 200 250 300 350 400 450 500
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Associated production with a bb pair
• Four-flavour scheme: LO cxn gg → bbΦ0
g
b
b
Φ0
q
q
logQ2
m2
b
g
g
b
b
Φ0
dominant
Q ∼ ( 110 ... 14 )MΦ
NLO with 0,1,2 high-transverse momentum b jets Dittmaier,Kramer,Spira,Walser;Dawson,Jackson,Reina,Wackeroth
large logs from phase space integration absorbed in bottom PDF
• Five-flavour scheme: LO cxn bb → Φ0
Φ0
b
b
NNLO
g
b
b
Φ0
NLO
Dicus,WillenbrockStelzer et al.;Balazs et al.Campbell et al.Harlander,KilgoreKidonakis
• Detailed comparisons: similar results√
Campbell et al.
• Further corrections: ◦ EW corrections to bb→ Φ0: few % (∼ ∆b)Dittmaier,Kramer,Muck,Schluter
◦ dominant t contr. to “NNLO” bbh: few % MH <∼ 120 GeV, several 10 % above Boudjema,
Ninh
◦ SUSY QCD to gg → bbh Gao et al.;Hollik,Rauch
◦ SUSY QCD to bb→ Φ0, bg → bΦ0: few % (∼ ∆b)Dawson,Jackson
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Associated production with a tt pair
(iv) Higgs tt production: pp → qq/gg → tt + HSM/ h(H, A)
g
t
t
Φ0
q
q g
g
t
t
Φ0
dominant
Kunszt;Gunion;Marciano,Paige
Significant role: MSMH
<∼ 150 GeV; light scalar MSSM Higgs
• ttH → ttγγ important contribution to H → γγ discovery contour
• ttH → ttbb important at LHC top Yukawa coupling Gunion et al.;Drollinger et al.
• NLO bkg ttbb, ttjj needed
• NLO QCD corrections (SM,MSSM): ∼ +20 % ∆theor ∼ 15 % Beenakker et al.;Dawson et al.
(MSSM QCD corrs: modified t, b Yukawa couplings)
• SUSY QCD corrections: 20-30 % Peng et al.Dittmaier et al. (→ talk M.Spira)
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Associated production with a W or Z boson
(v) pp → qq → Z∗/W ∗ → Z/W + HSM/ h, H
W, Z
W, Z
h, Hq
q
Glashow et al.Kunszt et al.
Contribution to Φ→ γγ discovery contour
• NLO QCD corrections (SM/MSSM) ∼ +30% (Drell-Yan) Han,Willenbrock
NNLO QCD corrections (SM/MSSM) ∼ +5-10% Hamberg,Van Neerven, MatsuuraBrein,Djouadi,Harlander
∆theor ∼ 5 %
• SUSY QCD corrections small Djouadi,Spira
• Full EW corrections (SM) ∼ −5-10% Ciccolini,Dittmaier,Kramer
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Charged Higgs Production
• Dominant: pp → qq, gg → H− + tb + c.c. g
g
t
b
H−
Bawa eal;Borzumati eal;Belyaev ealNLO QCD & SUSY QCD corrs.: 50...100 % Peng et al.
Dittmaier et al. (→ M.Spira)
scale dependence reduced: ∆ <∼ 15 %
LO cxn: gb → H−t + c.c.
NLO SUSY QCD corrs.: significant Zhu; Plehn; Berger eal;Gao et al.
• H± pair production pp → qq → H+H− q
q
H+
H−
γ, ZNLO QCD corrs.: ∼ 30 % (← Drell-Yan)
genuine SUSY QCD corrs.: small Djouadi,Spira
• pp → gg → H+H− (LO)Willenbrock;Krause eal;Jiang eal;Brein,Hollik;Barrientos eal
pp → bb → H+H− Barrientos eal;Hong-Sheng eal
SUSY-QCD significant
pp → gg → H+W − + c.c. (LO) Barrientos et al.;Brein et al.
pp → bb → H+W −+c.c.
Dicus eal;Barrientos eal;Brein eal;Hollik eal;Zhao ealQCD corrs. moderate
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Charged Higgs Boson discovery reach
Berger et al.
10-1
1
200 300 400 500
σtot (pp→tH−+X) [pb]
tanβ = 30
mH[GeV]
σincl,NLO
σincl,LO
σoff-shell
σBW
σsum
mt=mH+mb±2Γt
150
CMS
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Search Channels & Backgrounds (1)
Higgs Search in gg fusion CMS
• pp → γγ + X: MSM
Φ<∼ 140 GeV
B bkg measurable from sideband interpolation
accurate theor. predictions exp. acc., detector performance
B H → γγ: full 2-loop QCD+EWPassarino eal;Djouadi eal;Degrassi,Maltoni
NNLO QCD mt →∞ Steinhauser
QCD corrs. to Q loops MMM,SpiraAglietti et al.
SUSY QCD corrs. Degrassi,Slavich
(MH � mlooppart)
B Irreducible bkg
γ
γ
NLO+fragmentation Binoth et al.
up to N3LO Bern,Dixon,Schmidt
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Search Channels & Backgrounds (1)
• H → W +W − → l+l−νν: 140 GeV <∼ MH<∼ 180 GeV early discovery
no bkg from sidebands
B NLO W+W− bkg w/ spin correlations Dixon eal;Campbell,Ellis
CMS
multiple gluon emission up to NLL Grazzini
B W decay spin correlations in MC@NLO Frixione,Nason,Webber
B gg → W+W− → lνl′ν′Binoth et al; Duhrssen et al.
B tt∗, t∗t∗ LO w/ spin corr.,ΓtKauer,Zeppenfeld
B tt NLO bkg w/ spin corr. (in MC@NLO) Bernreuther eal
• H → ZZ → 4l: 140 GeV MH>∼ 180 GeV CMS
B bkg from data, acc. predictions to study nature of Higgs
B ZZ bkg up to NLO w/ spin corr. Dixon et al.;Campbell,Ellis
soft gluon impact on signal & bkg Frederix,Grazzini
gg → Z∗Z∗ → 4l Binoth,Bauer,Mertsch
B full QCD+EW corr. to H → W +W−/ZZ → 4l Bredenstein et al.
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Selection Cuts, Distributions
Impact of HO corrs on rate & shape of distributions may be strongly dependent on cuts!
B NLO gg → H + 1jgg → H + 2j
at large pT for mt →∞De Florian,Grazzini,Kunszt
Campbell,Ellis,Zanderighiin parton level MC progs
Parton shower effects on relevant distributions Del Duca et al.
B MSSM: only LO H + 1jBrein,HollikField,Dawson,SmithLangenegger et al.
B NNLO gg fusion taking into account exp. cuts for
h→ γγ
h→W+W− → l+l−νν
h→ ZZ → 4l
Catani,de Florian,Grazzini
Anastasiou,Melnikov,Petriello
Anastasiou,Dissertori,Stockli
Catani,Grazzini
+ implementation in MC programs
B gg → H : pT distribution, for pT � mH large logs Hinchliff,Novaes;Kauffman
resummed Higgs pT distributionBalazs,Yuan;Berger,Qiu;Kulesza,Sterman,VogelsangBozzi,Catani,de Florian,Grazzini
B NLO W+W− + jDittmaier,Kallweit,UwerCampbell,Ellis,ZanderighiBinoth,Guillet,Karg,Kauer,Sanguinetti
bkg to VBF, gluon gluon fusion
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Effects of cuts
NLO,NNLO K-factors vs pvetot
Fixed-order calc valid? Resummation needed?
Anastasiou et al. Anastasiou et al.
K-factors depend strongly on cut value
Fixed order Higgs prod cxn (NNLO) &
MC@NLO (rescaled w/ NNLO/NLO
K fac for σtot)Very good agreement!
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Search Channels & Backgrounds (2)
Higgs Search in Vector Boson Fusion
B gg → H + 2j (bgk to HWW, HZZ coupling isolation), WW + j, see previous slide
• Φ → γγ:
q
g
g
g
g
γ
γ
+ q
g
g
g
g
γ
γ
B bkg pp→ γγjj desirable
• Φ → τ+τ−: important MSSM discovery channel CMS
B QCD Zjj and EW Zjj bkgs at NLO Campbell,EllisOleari,Zeppenfeld
• Φ → W +W − → l+l−νν: most challenging! ATLAS
B WW bkg at NLO Jager,Oleari,Zeppenfeld+Bozzi
parton-level MC w/ full exp. cuts
B NLO to tt+jet Dittmaier,Uwer,Weinzierl
needed: top decay w/ full spin corrs. & finite width effects
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Expected Accuracies
Duhrssen et al. ATLAS
[GeV]Hm110 120 130 140 150 160 170 180 190
(H,W
)2
(H,X
) / g
2g
(H,W
)2
(H,X
) / g
2 g
∆
0
0.2
0.4
0.6
0.8
1
(H,W)2(H,Z) / g2g
(H,W)2) / gτ(H,2g
(H,W)2(H,b) / g2g
(H,W)2(H,t) / g2g
without syst. uncertainty
ATLAS + CMS-1
L dt=300 fb∫each
∫Ldt = 300 fb-1
mA = 150 GeV
tanβ
∆tan
β/ta
nβ (%
)
1 10
4
5
6
7
8
910
20
Kinnunen eal
)2
(GeV/cAm0 100 200 300 400 500 600 700 800 900
(%)
β/t
anβ
tan
∆
0
5
10
15
20
25
30
/lj/jjµe→ττ→SUSYH
ll/lj/jj→ττ→SUSYH
-130 fb
Total uncertainty
= 20
βta
n = 30β
tan = 40β
tan CMS
Stat errors
= 20β
tan = 30β
tan = 40
βtan
L/L = 5%∆ = 20%σ/σ∆
BR/BR = 3%∆
2 = 2450 GeV/ctA2 = 300 GeV/cµ
2 = 200 GeV/c2M
2 = 1 TeV/cSUSYm
= 10βtan
= 10βtan
•δMH
MH∼ 10−3
•δ tan βtan β ∼ 10− 15 %
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Higgs Search in SUSY Particle Final States
B Decays in gauginos and sfermions (3rd generation) important, if kinematically allowed.HDECAY
BR(Φ→χχ)tgβ = 3M2 = 140 GeVµ = 160 GeV
A
HH±
MΦ [GeV]100 200 500 1000
BR(Φ→squarks)
tgβ = 3
M~ Q = 400 GeV
At = 1.05 TeV
A
H
H±
MΦ [GeV]300 500 700 1000
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
10 3
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
300 400 500 600 7008009001000
B Four-lepton LHC events from MSSM Higgs boson decays into neutralino and chargino pairs
Event-generator level simulations w/ realistic detector effects and analyses of all significant bkgs
MA (GeV)
tan
β
MSSM Point 1*
from Ref. [8]
∫ Ldt = 100 fb-1
∫ Ldt = 300 fb-1
χ χ~~2
0
20
MA (GeV)
tan
β
MSSM Point 1*
from Ref. [8]
∫ Ldt = 100 fb-1
∫ Ldt = 300 fb-1
Bisset,Li,Kersting,Moortgat,Moretti
(µ, M2, M2, mlsoft, mτsoft
) =
(−500, 180, 90, 250, 250) GeV
Φ0 → χ02χ
02 totally dominates
Part of difficult wedge region (only h discovery)
can be covered
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Higgs Search in SUSY cascade decays
B Few scenarios considered Datta,Djouadi,Guchait,Moortgat
Sc3 pp → gg, qq, qq∗, qg → χ±
2 , χ03, χ
04 + X
→ χ±
1 , χ02, χ
01 + h, H, A, H± + X
Sc4 pp → gg, qq, qq∗, qg → χ±
1 , χ02 + X
→ χ01 + H±, h, H, A + X
0
10
20
30
40
50
60
70
80
90
0 50 100 150 200 250 300 350 400
bb invariant mass (GeV)
Eve
nts
/ 5
GeV
0
10
20
30
40
50
60
70
80
90
0 50 100 150 200 250 300 350 400
bb invariant mass (GeV)
Eve
nts
/ 5
GeV
green - SM tt red - SUSY bkg
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Higgs Search in SUSY cascade decays
B Few scenarios considered Datta,Djouadi,Guchait,Moortgat
Sc3 pp → gg, qq, qq∗, qg → χ±
2 , χ03, χ
04 + X
→ χ±
1 , χ02, χ
01 + h, H, A, H± + X
Sc4 pp → gg, qq, qq∗, qg → χ±
1 , χ02 + X
→ χ01 + H±, h, H, A + X
Difficult region of low MA and low tanβ can be explored
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Conclusions
• Higgs particle searches at the LHC belong to major endeavours
• LHC will find at least one Higgs boson [light scalar]
• Most (SUSY) QCD corrections know
Large corrections in several cases
remaining theoretical uncertainties: ∼ 100 % → <∼ 15 %
• Signal programs available including many of these corrections
(HIGLU,VV2H,V2HV,FEHIP,HNNLO,...)
• NLO MC’s include NLO corrections to many bkg processes, too
(MCFM,MC@NLO,Sherpa,...)
• Some processes still missing (e.g. NLO ttbb), still work to be done
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Expected relative error on σ determination at the LHC
From: Rainwater,Spira,Zeppenfeld
B Sumarizes results byZeppenfeld,Kinnunen,Nikitenko,Richter-Was (2000);Drollinger,Muller,Denegri (2001)(ttH, H → bb, black dotted)Maltoni,Rainwater,Willenbrock (2002)(ttH, H → W +W−)
B
∫L = 200 fb−1, for ttH :
∫L = 300 fb−1
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
Higgs Boson Branching Ratios and T otal W idth
HDECAY
BR(H)
bb_
τ+τ−
cc_
gg
WW
ZZ
tt-
γγ Zγ
MH [GeV]50 100 200 500 1000
10-3
10-2
10-1
1
10 2 10 3
• MH <∼ 140 GeV: H → bb dominant
• MH >∼ 140 GeV: H →WW ∗, ZZ∗
• BR(H → tt) up to 20 % above the tt threshold
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
MSSM Higgs Boson Branching Ratios
HDECAY
BR(h)tgβ = 3
bb_
τ+τ−
cc_
ggWW
γγ
Mh [GeV]
1
BR(h)tgβ = 30
bb_
τ+τ−
gg
WW→
←ZZ
←gg
←cc_
←γγ
Mh [GeV]
1
10-3
10-2
10-1
80 85 90 95 100 10510
-3
10-2
10-1
80 90 100 110 120
BR(H)
tgβ=3bb_
gg
τ+τ−
cc_
bb (tgβ=30)_
τ+τ−(tgβ=30)
MH [GeV]100 200 300 500 1000
BR(H)
tgβ=3
hh hh
WW
ZZ
tt-
ZA
MH [GeV]100 200 300 500 1000
10-2
10-1
1
10 2 10 3
10-2
10-1
1
10 2 10 3
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
MSSM Higgs Boson Branching Ratios
HDECAY
BR(A)tgβ = 3
bb_
τ+τ−
gg
Zh
tt_
MA [GeV]100 200 500 1000
1
BR(A)tgβ = 30
bb_
τ+τ−
ggtt_
MA [GeV]100 200 500 1000
1
10-3
10-2
10-1
10 2 10 3
10-3
10-2
10-1
10 2 10 3
BR(H±)tgβ = 3
τν
WAcbcs
µν
Wh
tb
MH± [GeV]
100 200 300 500
1
BR(H±)tgβ = 30
τν
cs
cb
µν
tb
MH± [GeV]
100 200 300 500
1
10-3
10-2
10-1
10 2
10-3
10-2
10-1
10 2
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
MSSM Higgs Mass Limits
B Direct Search at LEP: e+e− → Z + h/H, A + h/H, νeνe + h/H
� ���������
�
� ��������
���
�
� ���
������
��
� !�
1
10
0 200 400
1
10
mA (GeV/c2)
tanβ
Excludedby LEP
mh-max(c)
Mh/H >∼ 91 GeV
MA >∼ 91.9 GeV
MH± > 78.6 GeV
0.5 < tanβ < 2.4 excluded
(only in this scenario, mt = 174.3 GeV!,
no significant changes for mt = 172.6 GeV)
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul
MSSM Higgs Boson Production at the LHC
Spiraσ(pp→h/H+X) [pb]√s = 14 TeVMt = 174 GeVCTEQ6M
Mh/H [GeV]
tgβ = 3gg→H
Hbb_
Htt_
Hqq
HZ HW
gg→h
hbb_
htt_hZ
hWhqq
h H❍ ❍100 200 500 1000
10-4
10-3
10-2
10-1
1
10
10 2
10 3
10 4
90100 200 300 400 500 600 700800900
σ(pp→h/H+X) [pb]√s = 14 TeVMt = 174 GeVCTEQ6M
Mh/H [GeV]
tgβ = 30
gg→H
Hbb_
Htt_HZ
HW
Hqq
gg→h
hbb_
htt_hZ
hWhqq
h H❍ ❍100 200 500 1000
10-4
10-3
10-2
10-1
1
10
10 2
10 3
10 4
90100 200 300 400 500 600 700800900
Production plots: MS = 1 TeV
• h→ γγ, bb
• H/A→ τ+τ−, µ+µ−
• H± → τντ
• and V V → h, H → τ+τ−
M.M. Muhlleitner, 16 June 2008, SUSY08, Seoul