Probing triple Higgs couplings at colliders
Abdesslam Arhrib (NTU, Tangier-Univ)
NTHU–07/05/2009
Collaborators: R.Benbrik, C.W.Chiang, C.H. Chen, R. Guedes, W.
Hollik, S. Penaranda and R. Santos
1
Outline
• Introduction: Higgs production and decays
• Two Higgs Doublets Models (2HDM) and its Decoupling regime
• Challenge of the decoupling limit
• Triple Higgs coupling from h0 → γγ, h0 → bb̄
• Triple Higgs couplings at LHC, ILC and γγ
• Conclusions
2
ALR
AlF B
Ae,τ
AbF B
AcF B
QF B
mW
ΓZ
Rℓ
σh
Rb
Rc
Ab
Ac
mt
∆α5 (mZ )
αS (mZ )
mH
mH (95%)
χ2 /dof
CL(χ2 )
Experiment
0.1513 (21)
0.01714 (95)
0.1465 (32)
0.0992 (16)
0.0707 (35)
0.23240 (120)
80.398 (25)
2495.2 (23)
20.767 (25)
41.540 (37)
0.21629 (66)
0.1721 (30)
0.923 (20)
0.670 (27)
172.6 (1.4)
0.02758 (35)
SM
0.1480
0.01642
0.1480
0.1037
0.0741
0.23140
80.374
2495.9
20.744
41.477
0.21586
0.1722
0.935
0.668
172.3
0.02768
0.1186
85
148
17.3/12
0.14
M.Chanowitz 0904.3570
2-1
Pull
1.6
0.8
-0.5
-2.8
-1.0
-0.8
0.9
0.3
0.9
1.7
0.7
-0.04
-0.6
0.07
0.2
-0.3
<
• Best fit analysis: MH = 84+34
−26 GeV which gives MH ∼ 154 GeV
at 95% CL. (LEP Higgs Working Group).
• New analysis with new fitting program gives MH = 116.4+18.3
−1.3
GeV H.Flacher et al, arXiv:0811.0009 [hep-ph]
• LEPII Experiments: MH > 114.4 GeV
• Unitarity constraint: MH <
∼ 700 GeV
• Requiring the SM to be extended up to ΛGU T = 1016 GeV, one
can get 130 <
∼ MH <
∼ 180 GeV.
• If the MH >
∼ 200 GeV, then there should be an additional new
ingredient that is relevant at the EWSB scale.
3
Higgs decays
1
0.1
bb
1000
WW
ZZ
tt
gg
10
H)
BR(
0.01
1
0.1
0.001
(H ) [GeV℄
100
ss
0.01
Z
0.001
0.0001
100
130
160
200
300
MH [GeV℄
500
700
100
1000
4
130
160
200
MH [GeV℄
300
500
700
1000
• At hadron colliders (LHC, Tevatron) the relevant processes are:
gg → hSM → γγ
gg → hSM → V V ∗
,
qq → qqV ∗ V ∗ → qqhSM
gg, qq → tt̄hSM
,
, hSM → γγ, τ + τ − , V V ∗
hSM → bb̄, W W ∗ , W W ∗
qq → hSM Z , qq ′ → hSM W
,
hSM → bb̄(Tevatron)
gg → hSM hSM (doubleHiggsproduction)
5
SM Higgs production
10 5
LHC
σ [fb]
gg → h
10 4
qq → qqh
10 3
qq → Wh
bb → h
10
gg,qq → tth
2
qb → qth
TeV4LHC Higgs working group
100
200
qq → Zh
300
400
500
mh [GeV]
6
Signal significance
Significance for the experimental detection
Low luminosity
H → γγ
ttH (H → bb)
H → ZZ(*) → 4 l
H → WW(*) → lνlν
∫ L dt = 30 fb
(no K-factors)
-1
ATLAS
10 2
qqH → qq WW(*)
qqH → qq ττ
Total significance
10
1
100
120
140
160
180
200
2
mH (GeV/c )
7
Signal significance
10 2
H → γ γ + WH, ttH (H → γ γ )
ttH (H → bb)
H → ZZ(*) → 4 l
H → WW(*) → lνlν
H → ZZ → llνν
H → WW → lνjj
Total significance
10
5σ
ATLAS
∫ L dt = 100 fb
(no K-factors)
1
10
2
-1
10
3
mH (GeV)
8
8-1
SM Higgs Branching Ratio
At linear colliders (LC)Experimental accuracy
1
bb
-1
10
+ -
τ τ
gg
cc
10
10
-2
-3
+
-
WW
γγ
100
110
120
130
9
140
150
160
M H (GeV)
Extended Higgs sector
• With Extended Higgs sector: 2HDM Φ1 , Φ2 , CP can be violated
either explicitly or spontaneously in Higgs sector T.D.Lee’73
• Some models of dynamical electroweak symmetry breaking yields
the 2HDM as their low-energy effective theory. [H. J. He et al,
PRD65, (2002) hep-ph/0108041].
• Models for phase transition require 2 Higgs doublets
• Neutrino masses, Dark Matter, BAU
Zee’80, Ma’06, Aoki, Kanemura, Seto’08
10
Coupling to fermions
• both Φ1 and Φ2 couple to fermions: Mq = Y u v1 + Y d v2 :
diagonalisation of Mq does not diagonalise similtanousely Y u,d :
FCNC at tree level: 2HDM-III
• 2HDM-I One doublet couple to gauge boson and the other one
couple to fermion (like in SM).
• To avoid FCNC at tree level, We impose Z2 symmetry (Weinberg
Theorem): Φ2 → −Φ2 , diR → −diR : 2HDM-II
• 2HDM-X or lepton-specific 2HDM (or Leptophilic Higgs): one
doublet generates the masses of the charged leptons and the
secon one generates the masses of the quarks
Barnet, Senjanovic, Wolfenstein and Wyler’84
11
V
+
+
2
2
= µ21 (Φ+
Φ
)
+
µ
(Φ
Φ
)
+
λ
(Φ
Φ
)
+
1
2
1
1
2
1
2
1
+
+
+
2
2
λ2 (Φ+
Φ
)
+
λ
(Φ
Φ
)(Φ
Φ
)
+
λ
|Φ
Φ
|
1
3
1
2
4
2
1
1
2
1
+
2
+{m212 (Φ+
1 Φ2 ) + h.c} + [λ5 (Φ1 Φ2 ) + h.c]
• One can have: Explicit CP
6
if ℑ(m412 λ∗5 ) 6= 0;
• One can have Spontaneous CP
6
if:
< Φ2 >= v2 eiθ
m212
| λ 5 v1 v2 |
< 1; < Φ1 >= v1 ,
• Five physical scalars (8 d.o.f=5+3): a charged Higgs pair H ± ,
two CP-evenh0 , H 0 and one CP-odd A0
• 10 parameters (λi )i=1,...,5 , µ21 , µ22 , m212 , v1 , v2 with
√
2
2
v1 + v2 = (2 2GF )−1 and 2 minimization conditions, We are left
with 7 parameters.
• mA , mh , mH , mH± , α, tan β = v1 /v2 and m212 free parameters.
12
Constraints on 2HDM parameters
Experimentals:
• Charged Higgs: e+ e− → (γ ∗ , Z ∗ ) → H + H − at LEPII followed by
H + → (τ ντ , cs̄); MH ± > 78.7 GeV:.
This limit apply to all models in which BR(H ± → τ ντ )+
BR(H ± → cs)=1.[L3: hep-ex/0309056, Delphi: hep-ex/0404012.]
• Neutral Higgs bosons: From e+ e− → h0 A0 at LEPII, OPAL
collaboration has put a limit on h0 and A0 masses of the 2HDM
assuming 100% decays of h0 and A0 into hadrons.
1<
∼ Mh <
∼ 55 GeV and 3 <
∼ MA <
∼ 63 GeV is excluded at 95% CL
independent of α and tan β. [Opal Collab hep-ex/0408097]
13
Theoretical constraints:
• b → sγ: mH± > 295 GeV, ∀ tan β in 2HDM-II. No such bound in
2HDM-I [P.Gambino et al, ’01,F.Borzumati et al ’98].
In 2HDM-X, light H ± is allowed Aoiki, H.Logan’09
• δρ ≤ 10−3 [(PDG)]: constrain the splitting MA and MH±
• Perturbativity on tan β: 0.1 ≤ tan β ≤ 70 [V.D.Barger ’90]
• Perturbativity on λi : |λi | ≤ 8π
• Potential bounded from bellow: λ1,2 > 0,
√
λ1 λ2 ≥ λ3 + λ4 + λ5
• Unitarity constraints: in 2HDM there is 14 constraints coming
from different channel:W + W − , ZZ, hh, HH, hH, AA, hA,
H + H − , hH + ... [A.Akeroyd, A.A and E.Naimi PLB’2000, A.A ’2000]
14
The decoupling limit of 2HDM
2
M12
→ ∞, cos(α − β) → 0
• In this limit, the masses of Φ=H, H ± , A:
X
2
2
2
λi v 2 + O(v 4 /M12
),
mΦ = M12 +
,
i
m2h
=
X
λi v 2
i
2
2
• When M12
≫ λi v 2 , m2H,A,H± are determined by M12
, and are
independent of λi . In this case α → β − π/2, The effective theory
below M12 is described by one Higgs doublet. In this limit:
h0 V V /(hSM V V ) = sin(β − α) → 1
cos α
sin α
0
0
→ 1 , (h t̄t)/hSM tt̄ =
→1
h bb̄/hSM bb̄ = −
cos β
sin β
H 0 V V ∝ cos(β − α) → 0 , (hhh)/(hhh)SM → 1
h0 H + H − , h0 A0 A0 , h0 H 0 H 0 , H ± tb̄... 6= 0
15
Challenge of the decoupling limit
In case of extended Higgs sector like MSSM or 2HDM we have 4
physical Higgs: 2 CP even (h0 ,H 0 ), 1 CP odd A0 and a pair charged
Higgs H±:
σ({pp, e+ e− } → Z + h0 /H 0 ) = sin2 / cos2 (β − α)σSM
σ(pp → W + h0 /H 0 ) = sin2 / cos2 (β − α)σSM
σ(e+ e− → A0 + h0 /H 0 ) = cos2 / sin2 (β − α)λσSM
σ({pp, e+ e− } → ν ν̄ + h0 /H 0 )sin2 / cos2 (β − α)σSM
{gg, γγ} → h0 , H 0 , A0
16
tanβ
50
ATLAS -ATLAS
300 fb
40
-1
maximal mixing
30
0
0
+
-
0
h H AH
20
0
0
h H
0
h H A
10
9
8
7
6
5
+
-
0
0
h only
4
0
3
LEP 2000
0
h H
LEP excluded
2
0
0
0
+
-
0
h H
h H AH
1
50
100
150
200
250
300
350
+
-
400
450
500
m A (GeV)
17
A program of precision measurements will begin at LHC and will
reach maturity at the ILC :
δ(ΓW )/ΓW ≈ 5 − 10% , δ(Γτ )/Γτ = δ(Γγ )/Γγ ≈ 18% at LHC
At Linear Collider(ILC), the situation is much better:
Relative accuracies (in %) on MH and couplings at ILC
R
GeV and L = 500 fb−1 [ hep-ph 0106315]
MH
∆MH
gHW W
gHZZ
gHtt
gHbb
gHτ τ
120
±0.033
±1.2
±1.2
±3.0
±2.2
±3.3
√
s = 500
In γγ option of ILC: δΓ(H → γγ)/Γ(H → γγ) ≈ 2% can be achieved
(from γγ → H → bb̄).
18
Non decoupling effects in Higgs decays
A.A, W.Hollik and S.Penaranda PLB’04
• h0 → γγ is loop-mediated processes since the photon does not
couple to neutral particles
γ
o
o
h
H
h
+
γ
H+
γ
γ
• The only pure 2HDM contribution comes from charged Higgs
loops (if α = β − π/2): h0 tt̄ ≈ csαβ ≈ 1...
2
2
g[h0 H + H − ] ≈ − 2MgW {Mh20 + 2(MH
± − M12 )}
The decoupling is achieved when M12 → ∞
19
• h0 → bb̄, already exists at the tree level because of the Higgs–b
Yukawa interaction
• Pure 2HDM one-loop contributions not present in the SM case:
b
A,H, H+
h
t, b
A,H, H−
b
α → β − π/2 ⇒ only h0 H + H − , h0 H 0 H 0 and h0 A0 A0 don’t vanish or
reduce to their SM values
g
2
2
{Mh20 + 2(MH
± − M12 )}
2MW
g
2
2
g[h0 H 0 H 0 ] ≈ −
{Mh20 + 2(MH
0 − M12 )}
2MW
g
2
0 0 0
{Mh20 + 2(MA2 0 − M12
)}
g[h A A ] ≈ −
2MW
g[h0 H + H − ] ≈ −
20
• Γγγ can be measured with 16% accuracy at ILC and Γbb with
2.2%.
• We want to distinguish 2HDM from SM in the decoupling
regime: (mA0 , mH , mH± ≫ mZ )
• In the numerical evaluation we have parameterized the Higgs
sector with:
Mh0 = 120 GeV , MH 0 = MA0 = MH ± , α ≈ β − π/2 , M12
21
0
h → γγ: ∆γγ =
Γ(h→γγ)2HDM −Γ(h→γγ)SM
|
Γ(h→γγ)SM
|
550
%
10
3−
10−
20%
615
%
>20
475
m12
<3%
10
%
390
3−
<3%
275
PSfrag replaements
5
MH +
400
600
800
M H + (GeV)
22
1000
h → bb̄: ∆bb =
Γ(h→bb)2HDM −Γ(h→bb)SM
|
Γ(h→bb)SM
|
10−
550
3−
20%
10
%
615
%
475
>20
<3%
m12
390
<3%
275
PSfrag replaements
5
MH +
400
600
800
M H+ (GeV)
23
1000
hhhef f from S.Kanemura, E.Senaha, Y.Okada, C.P.Yuan PLB’02,
In the decoupling limit hhhef f takes the following form
)
(
3
Nct m4t
3Mh2
m4Φ
m212
− 2 2 2 ,
hhhef f =
1+ 2 2 2 1−
2
2
2
v
3π mh v
3π mh v
sin β cos βmΦ
with mΦ = mH = mA = mH± .
24
300
M=0 (Max. Non−Decoupling Case)
2
mh=100GeV
200
/λhhh
120
2
100
160
∆λhhh
THDM
mH+=mH=mA (=mΦ)
√q =2mh
SM
(%)
sin (α−β)=1
0
100
200
300
mΦ (GeV)
400
500
f
ef f
HDM
≡ λef
(T
HDM
)
−
λ
∆λThhh
hhh
hhh (SM ). The results of the full
one-loop calculation are shown as solid curves.
25
1. Probing triple Higgs couplings in the 2HDM at e+ e− collider
A.A, R.Benbrik and C.W. Chiang’08
• If the Higgs exist, it will be produced either at Tevatron-II or
LHC.
• In order to establish the Higgs mechanism, we need to measure
the Higgs couplings to fermions, to gauge boson as well as the
self-interaction of Higgs bosons.
• Complementarity of LHC/ILC [G. Weiglein et al, “Physics interplay
of the LHC and the ILC,” Phys. Rept’06, hep-ph/0410364 ]
• SM scalar potential can be reconstructed by measuring the triple
coupling λhhh and quartic coupling λhhhh .
• One can access to λhhh at ILC from e+ e− → Zhh
26
e+ e− → Zhh in SM
H
H
e
H
e
Z
Z
e
e
H
H
H
Z
Z
H
G0
e
e
Z
Z
H
H
Z
e
e
Z
Z
H
H
Z
e
Z
e
H
e
G0
• In SM, σ(e+ e− → Zhh) is rather small, for
GeV, σ(e+ e− → Zhh) = 0.2 fb
H
Z
e
Z
Z
√
s, mH = 500, 120
• possible to extract a signal from EW and QCD background
e+ e− → Zbbb̄b̄ by simple kinematics cuts: e.g, invariant masses...
Much more events are possible if: [D.Miller et al hep-ph/9906395]
• Very high luminosity
• Excellent b tagging
• Beam polarization.
27
e
h
h0
e
Z
SM
Z
SM
decouple
Z
Z
h0
SM
Z
e
e
0
decouple
Z
e
Z
h
Z
e
G
0
decouple
e
Z
Z
h
0
SM
h0
Z
e
h0
0
G0
e
Z
h0
h0
A
e
Z
h0
A0
e
Z
h0
Z
e
e
h0
h0
H0
e
Z
h0
e
Z
h0
h0
h0
e
Z
e
→ h0 h0
h0
0
e
e
Z
SM
h0
Z
e
Z
SM
In 2HDM we are sensitive to:
−3e
3
2
3
2
2
hhh =
(c
c
−
s
s
)s
m
0 − cβ−α cβ+α m12
β
β
2β
α
α
h
mW sW s22β
1 ecβ−α
2
2
2
Hhh = −
)s
s
−
(3s
−
s
)m
+
m
(2m
0
0
2α
2β
2α
2β
12
H
h
2 mW sW s22β
28
e+ e− → Zhh in the decoupling limit: mΦ = mH = mA = mH±
)
(
3
m4Φ
m212
3Mh2
Nct m4t
1+ 2 2 2 1−
hhhef f =
− 2 2 2 ,
2
2
2
v
3π mh v
3π mh v
sin β cos βmΦ
10
m12=0 GeV
m12=200
m12=300
m12=500
SM
σ(e+e- -->hhZ) (fb)
σ(e+e- -->hhZ) (fb)
10
1
0.1
300 400 500 600 700 800 900 1000
mΦ (GeV)
m12=0 GeV
m12=200
m12=300
m12=500
SM
1
0.1
300 400 500 600 700 800 900 1000
mΦ (GeV)
√
√
mh = 120 GeV, s = 500 GeV (left) and s = 800 GeV (right).
Away from decoupling limit one can reach 100 fb for ZΦi Φj .
29
10
10
Hhh
hhh
λ2HDM/λSM
λ2HDM/λSM
Hhh
hhh
1
1
0
1
1.5
2
2.5
3 3.5
tanβ
4
4.5
5
50 100 150 200 250 300 350
m12 (GeV)
mh , MH , MA , MH± = 120, 300, 350, 300 GeV, sin α = −0.9,
1<
∼ tan β <
∼ 10, m12 ∈ [0, 600] GeV
30
e+ e− → ZΦi Φj
m12 = 0, mH± = 250 GeV , tan β = 10
Zhh, mh,H,A = 120, 240, 150 GeV , sin α = 0.8
ZAA, mh,H,A = 120, 200, 100 GeV , sin α = 0.6
ZHH , mh,H,A = 120, 140, 360 GeV , sin α = −0.1
ZhH , mh,H,A = 120, 200, 300 GeV , sin α = −0.7
103
σ(e- e+ → Z Φi Φi)[fb]
A0 A0
0 0
102
h h
H0 H0
1
10
h0 H0
100
300
400
500
600
700
√s(GeV)
31
800
900
1000
Probing triple Higgs couplings in the 2HDM at γγ collider
A.A, R.Benbrik and C.H.Chen and R.Santos’09
• γγ → hh is loop medited, then very sensitive to new physics.
• γγ → hh has more phase space than e+ e− → Zhh
φ
(v1 )
φ
(v2 )
φ
φ
(v3 )
(v4 )
(v5 )
φ
(v6 )
(v7 )
(v8 )
(v9 )
φ
(v11 )
(v12 )
32
(v10 )
Just charged Higgs contribution are shown
In 2HDM, scalar loops dominate
(b1 )
(b2 )
(b3 )
(b4 )
(b5 )
(b6 )
(b7 )
(b8 )
(b9 )
(b10 )
(b11 )
(b12 )
(b13 )
www.FeynArts.de , FormCalc , LoopTools, (T.Hahn)
33
γγ → HH in SM
Jikia’92, Belusevic’04 and Takahashi’08
• look for γγ → HH → 4b
• Main background from W + W − and from non-resonant four jet
final state.
• Select 2 jet and reconstruct Higgs mass, M (q q̄ − M H) < 5 GeV
• Conclusion: For a center of mass energy of 350 GeV and
mH = 120 GeV an integrated luminosity of 450 fb−1 would be
needed to exclude a zero Higgs boson self-coupling at the 5 σ
level.
34
5
700
σ2HDM > 100 σSM
3
50σSM< σ2HDM < 100 σSM
2
σ2HDM > 100 σSM
mH0 (GeV)
tanβ
50σSM< σ2HDM < 100 σSM
600
σSM< σ2HDM < 50 σSM
4
σSM< σ2HDM < 50 σSM
500
400
300
200
1
0
100
200
300
m12 (GeV)
0
400
100
200
300
m12 (GeV)
400
mh0 = 115 GeV, mA0 = 270 GeV , mH ± = 350 GeV.
Left mH 0 = 2mh0 , Eγγ = 500 GeV, −1 ≤ sin α ≤ 1, 1 <
∼ tan β <
∼ 10
and right tan β = 1, sin α = −0.9, Eγγ = 800 GeV
35
10-1
100
Total
γγ→h0h0
-2
-1
mH± = 200 GeV
10
(+ +)
10-3
σ (pb)
σ (pb)
10
γγ→h0h0
SM
10-4
(+ -)
mH± = 250 GeV
10-2
= 300 GeV
10-3
SM
-5
-4
10
10
10-6
10-5
400
600
800 1000 1200 1400
Eγγ (GeV)
36
400 600 800 1000 1200 1400
Eγγ (GeV)
Decoupling limit, mh = 120 GeV
10
Decoupling Limit (Eγγ = 500 GeV )
10
Decoupling Limit
1 loop m12 = 0
MΦ = 300 GeV ; m12 = 200 GeV
2 loop m12 = 0
1
2 loop m12 = 200 GeV
σ(γγ → h0 h0 ) (f b)
σ(γγ → h0 h0 ) (f b)
1 loop m12 = 200 GeV
MΦ = 300 GeV ; m12 = 0
MΦ = 400 GeV ; m12 = 0
MΦ = 500 GeV ; m12 = 0
SM
1
SM
0.1
200
400
600
800
1000
1200
1400
200 250 300 350 400 450 500 550 600 650
MΦ
1600
Eγγ
(Left) γγ → hh at LO,
(Right) γγ → hh at LO and LO + High order corrections to hhh
37
3. Probing triple Higgs couplings in the 2HDM at LHC
(A.A, R.Benbrik, C.H. Chen, R. Guedes and R.Santos’09)
g
g
g
um
H
F
F
H
S
F
g
um
H
H
um
dm
F
H
H
dm
g
g
T1 C4 N5
g
dm
dm
g
H
H
g
um
g
um
g
g
H
dm
H
g
T3 C2 N13
g
um
g
um
T4 C1 N17
dm
F
g
H
g
H
um
H
g
um
dm
H
g
g
um
H
g
um
dm
g
H
T4 C2 N18
dm
T4 C3 N19
38
H
g
H
H
F
H
g
F
F
F
H
T4 G1 N16
H
dm
um
T3 C1 N12
dm
dm
H
um
g
T3 C4 N15
H
um
um
F
dm
H
um
H
F
um
um
g
T3 G1 N11
dm
dm
um
g
F
H
um
T2 C2 N8
g
H
dm
dm
H
g
T2 C1 N7
T3 C3 N14
H
um
dm
um
um
g
H
T2 C4 N10
um
um
F
dm
T2 C3 N9
g
um
F
T1 C3 N4
H
um
T2 G1 N6
dm
dm
g
H
F
H
H
dm
T1 C2 N3
g
H
H
dm
g
T1 C1 N2
g
H
H
um
g
T1 G1 N1
dm
H
um
g
dm
g
um
H
dm
H
g
dm
g
H
dm
dm
T4 C4 N20
dm
H
• In SM, the cross section is small 1 <
∼ σ(gg → HH) <
∼ 3 fb for
120 <
∼ MH <
∼ 190 GeV.
• 150 <
∼ MH <
∼ 200 GeV, from
gg → HH → W + W − W + W − → 2l4j or 3l2j, the non vanishing
of the triple Higgs coupling of the SM can be established at 95%
CL (with 300 fb−1 ).
• One need VLHC to measure the triple Higgs coupling of the SM
with an accuracy of 8-25% at 95% CL.U. Baur et al ’03
• MH <
∼ 140 GeV, gg → HH → bb̄γγ, look promissing. With 600
fb−1 or more, we could make a rough first measurement for
MH = 120 GeV (with 6 signal events). U. Baur et al ’04
39
100
m12 = 200GeV
m12 = 300GeV
10
m12 = 350GeV
σ(gg → h0 h0 )(pb)
SM
1
0.1
0.01
0.001
60
80
100
120
140
mh0 (GeV )
160
180
200
mH 0 = 200GeV, mA = 200GeV, mH ± = 300GeV, sin α = 0.631 and
tan β = 1. (sin(β − α) = 0.1)
40
500
m12 (GeV)
400
300
200
100
0
200 250 300 350 400 450 500 550 600
mH0 (GeV)
mh = 115, mH± = 300, mA = 100 GeV sin α = −0.9, tan β = 1,
200 <
∼ mH <
∼ 600 GeV, 0 <
∼ m12 <
∼ 400 GeV.
σ2HDM < σSM , σ2HDM > 100σSM , σSM <
∼ σ2HDM < 100σSM ,
41
Decoupling limit
100
-200
boxes
SM
(+ -)
Decoupling limit
(+ +)
-400
m12 = 300 GeV
0
-600
200
-800
100
λeff(hhh)
σ (pb)
10-1
SM
10-2
0
-1000
200
100
-1200
-1400
-1600
m12 = 300 GeV
-1800
10-3
300 350 400 450 500 550 600 650
mΦ(GeV)
-2000
300 350 400 450 500 550 600 650
mΦ(GeV)
42
Higgs signatures
Model I
1
h0 → bb̄
tan β = 1
mh0 = 110 GeV
1
h → γγ
Mh = 80GeV
0
+ −
h →τ τ
0.1
h → W ∗W ∗
0.1
h0 → cc̄
h0 → gg
0.01
Br
h0 → W ∗ W
0.001
h0 → Z ∗ Z
0.001
0.01
h → Z ∗Z ∗
h0 → γγ
-1
-0.5
0
0.5
0.0001
−8π
1
sin α
43
−6π
−4π
−2π
0π
λ5
2π
4π
6π
8π
Higgs signatures
1
1
h0 → bb̄
h0 → cc̄
0
Light Higgs Branching Ratios
h → gg
h0 → τ + τ −
h0 → bb̄
tan β = 1
mh0 = 110 GeV
h0 → cc̄
h0 → gg
0
+ −
0.1 h → τ τ
0.1
h0 → W ∗ W
h0 → W ∗ W
h0 → Z ∗ Z
0.01
0.01
h0 → γγ
0.001
-1
-0.5
tan β = 1
mh0 = 110 GeV
h0 → Z ∗ Z
h0 → γγ
0.001
0
0.5
1
h0 → µ+ µ−
-1
-0.5
sin α
0
sin α
Left: 2HDM-II , Right 2HDM-X (leptophilic Higgs)
44
0.5
1
Conclusions
• LHC will be capable to discover the Higgs bosons and measure
its coupling to top quark, τ lepton, W and Z with 10–30%
accuracy (L = 300f b−1 ).
• At LC, the precision of the measurement is about 1–2%, such
precision is needed to distinguish between models.
• In 2HDM, non decoupling effects could be large to be measured
both at LHC and ILC and its γγ option.
• If 2HDM Higgs masses are not too heavy, their triple self
couplings can be accessible at LHC and ILC
45