Standard Model Theory
XLIV International Meeting
on Fundamental Physics
Universidad Autonoma, MADRID
4 – 8 April, 2016
W. H OLLIK
M AX -P LANCK -I NSTITUT F ÜR P HYSIK , M ÜNCHEN
Outline
The Standard Model in the pre-Higgs era
The Standard Model in the Higgs era
The status of Standard Model
Future prospects
the rise of the EW Standard Model
the symmetry group SU(2) × U(1)
– discovery of neutral currents 1973
the W and Z bosons
– discovery 1983 at SPS (CERN)
the coupling structure from local gauge invariance
– precise measurements at LEP/SLC 1989 - 2000
the Higgs mechanism and Yukawa interactions
– top discovery at Tevatron 1995
– Higgs discovery at LHC 2012
precision physics: major role in establishing the SM
restricting BSM physics
interactions from gauge-symmetric Lagrangian
fermion–vectorbosons
vectorboson self interactions
(fields and momenta incoming)
f
Wµ+
Aµ
f¯
Feynman rules:
Vρ
Wν−
f
Wµ
f¯′
Wµ+
Vρ
f
Wν−
Vσ′
Zµ
f¯
coupling constants:
gem = e,
gweak = e/ sin θw
group entries:
isospin I3f ,
charge Qf
interactions from symmetry-breaking Lagrangian
WWH and ZZH couplings
µ
V
W
H H m2W µν
2i
g
v
W
Vν
ZV
µ
H H m2Z µν
2i
g
v
ZVν
WWHH and ZZHH couplings
Vµ
Vµ
H
H
W
m2W µν
2i 2 g
v
WVν
H
H
H
H
Z
m2Z µν
2i 2 g
v
H
H
ZVν
Fermion-Higgs coupling
f
H
mf
−i v
couplings proportional to masses
f
Cubic and Quartic self-couplings
HH
H
HH
H −3i
m2H
v
HH
H
H
HH
H
H
m2H
−3i 2
v
Higgs boson probably found, all other particles
confirmed
consistent quantum field theory
in accordance with unitarity
renormalizable ⇒ predictions at higher orders
formal parameters:
physical parameters:
g2 , g1 , v, λ, gf , VCKM
α, MW , MZ , MH , mf , VCKM
observables and experiments
•
Muon decay:
µ− → νµ e− ν̄e
determination of the Fermi constant
µ−
παMZ2
W
•
•
+ ...
Gµ = √
2 (M 2 − M 2 )
2MW
W
Z
e+ e− → Z → f f¯
Z production (LEP1/SLC):
e+
various precision measurements at the
Z resonance: MZ , ΓZ , σhad , AFB , ALR , etc.
γ, Z
e−
⇒ good knowledge of the Zf f¯ sector
W-pair production (LEP2/ILC):
W
e+
γ, Z
e−
W
W
e+
νe
e−
W
e+ e− → WW → 4f (+γ)
– measurement of MW
– γWW/ZWW couplings
– quartic couplings: γγWW, γZWW
experiments at hadron colliders
•
p
– measurement of MW
W
p, p̄
•
pp, pp̄ → W → lνl (+γ)
W production (Tevatron/LHC):
– bounds on γWW coupling
top-quark production (Tevatron/LHC): pp, pp̄ → tt̄ → 6f
W
p
t
t̄
p, p̄
b
b̄
– measurement of mt
W
• Higgs production (LHC):
pp → H → γγ, ZZ, . . .
H
t
t
t
H
W, Z
W, Z
input quantities
GF
= 1.1663787(6) · 10−5 GeV−2
MZ
= 91.1875 ± 0.0021 GeV
MW
= 80.385 ± 0.015 GeV
mt
= 173.2 ± 0.9 GeV
MH
= 125.09 ± 0.24 GeV
αs (MZ )
= 0.1185 ± 0.0006
precise experiments . . .
. . . need precise calculations
Test of theory at quantum level:
Sensitivity
to looptheorretions
role of theory:
exploiting
quantum structure
X
sensitivity to heavy internal particles (X)
+
Standard Model:
X = Higgs, top
Very high auray of measurements and
theoretial preditions needed
electroweak precision observables
Whih model ts better?
Does the predition
µ lifetime:
GF of a model ontradit the
experimental data?
2
Z observables:
MZ , ΓZ , sin θeff , . . .
S. Heinemeyer, High Energy Physis Seminar, 02/20/02
LEP 2, Tevatron, LHC:
low energy:
(g − 2)µ
MW , m t
+ MH
4
Constraints on the Standard Model Higgs from
eletroweak preision tests
MW
– MforZ Mcorrelation
Theoretial
predition
W in the SM:
Denition of Fermi onstant GF via muon lifetime:
G2F m5
3
0
!
2
me m2
1 + 35
1
m2 A
2
MW
(1 + q)
192
q: QED orretions in Fermi Model,
inluded in denition
1 =
F
[R. Behrends, R. Finkelstein,
A. Sirlin
µ−
− ℄
[T. van Ritbergen, R. Stuart W'99
νµ
'56
℄
e−
νe
[higher
orders]
Comparison with SM predition for+ muon
deay:
⋆
⋆
GF
πα
√ =
2
2
2
MW 1 − MW /MZ
2
⇒
⇒
prediction
)
!
2
MWother parameters
2 W from
of
M
p
MW
r
2
MZ
GF
each amplitude
1
= 2 (1 + ) ;
∼ GF requires these higher-order terms
m
loop orretions
Constraints on the Standard Model Higgs from
eletroweak preision tests
MW – MZ correlation
Theoretial predition for MW in the SM:
Denition of Fermi onstant GF via muon lifetime:
1 =
G2F m5
3
F
0
!
2
me m2
1 + 35
1
m2 A
2
MW
192
q: QED orretions in Fermi Model,
inluded in denition
[R. Behrends, R. Finkelstein,
−
[T. van Ritbergen,µR. Stuart
(1 + q)
νµ
A. Sirlin '56
℄
℄
'99
W
e−
−
νe
Comparison with SM predition for muon deay:
νµ
µ
)
W
e
2
MW
νe
µ
1
2 !
MW
e
MZ2νe
νµ
W
νµ
p
=
2GF (1 + r) ;
W
µ
W
µ
e
νe
νµ
m
e
νe
loop orretions
ln mE O(1)
quantum
(1%) = 100GeV
[0 2%orretions,
6%℄ Oof(1)Ofor
:::
vector-boson mass correlation
GF
√
2
=
2
MW
πα
2
2
1 − MW /MZ
:
determines W mass
MW = MW (α, GF , MZ , mt , MH )
complete at 2-loop order α2 and ααs
:::
1-loop entries
E
ontain all details of the theory
top quark
· (1 + ∆r)
∆r :
quantum correction
∆r = ∆r(MZ , MW , mt , MH )
2
e
W
t
b
H
W
e
Higgs boson
W
W
W
e
W
e
e
gauge-boson self-ouplings
W
Z; W
e
e
) allow for indiret experimental tests
of not diretly aessible quantities
Ansgar Denner
28
24. J
dominant contributions to ∆r
∆r = ∆α −
c2w
∆ρ
s2w
+ ···
Large universal terms:
∆α = Πγferm (MZ2 ) − Πγferm (0) = 0.05907 ± 0.0001
∆ρ =
ΣZ (0)
2
MZ
−
ΣW (0)
2
MW
=
GF m2t
3 8π2 √2
= 0.0094
beyond 2-loop order: ∆ρ(3) + ∆ρ(4)
[one-loop]
→
1
1−∆α
∼ αt
αs2 αt , αs αt2 , αt3 , αs3 αt
∼
reducible higher order terms from ∆α and ∆ρ via
1 + ∆r
∼
m2t
v2
c2
1+ w
s2
w
∆ρ +···
photon vauum polarization
−
γ
Πγferm (MZ2 )
−
γ
Πγferm (0)
≡ ∆α
1
α
≃
→ α(MZ ) =
1 − ∆α
129
∆α = ∆αlept + ∆αhad ,
∆αlept = 0.031498 (4 − loop)
∆αhad = 0.02757
± 0.00010
= 0.027626 ± 0.000103
= 0.027504 ± 0.000118
Steinhauser 1998; Sturm 2013
Davier et al. 2010
Hagiwara et al. 2011
Jegerlehner 2015
significant parametric uncertainty
∆αhad
α 2
= − MZ Re
3π
Z
∞
4m2π
Rhad (s′ )
ds ′ ′
s (s − MZ2 − iǫ)
′
Rhad =
σ(e+ e− → γ ∗ → hadrons)
σ(e+ e− → γ ∗ → µ+ µ− )
Jegerlehner 2015
EW 2-loop calculations for ∆r
Freitas, Hollik, Walter, Weiglein
Awramik, Czakon
Onishchenko, Veretin
Degrassi, Gambino, Giardino
universal terms at 3- and 4-loops (EW and QCD)
van der Bij, Chetyrkin, Faisst, Jikia, Seidensticker
Faisst, Kühn Seidensticker, Veretin
Boughezal, Tausk, van der Bij
Schröder, Steinhauser
Chetyrkin, Faisst, Kühn
Boughezal, Czakon
Chetyrkin, Faisst, Kühn, Maierhofer, Sturm
80.45
MW=80.385 ± 0.015 GeV
MW (GeV)
80.40
80.35
Mt=173.2 ± 0.9 GeV
80.30
80.25
100
150
200
250
MH (GeV)
variation of ∆r by 0.001
present exp. error:
δ ∆α = 10−4 :
⇒
300
350
400
δMW = 18 MeV
∆MW = 15 MeV / theo: 4 MeV
∆MW = 1.8 MeV
cross section [nb]
Z resonance
30
20
2ν
LEP:
ALEPH
DELPHI
L3
OPAL
3ν
4ν
e
+
f
data
Z
10
0
86
88
90
92
94
cms energy [GeV]
-
e
f
• effective Z boson couplings with higher-order ∆gV,A
gVf → gVf + ∆gVf ,
gAf → gAf + ∆gAf
• effective ew mixing angle (for f = e):
e
2
2
g
M
M
1
1 − Re Ve
= 1 − W2 + W2 ∆ρ + · · ·
sin2 θeff =
4
gA
MZ
MZ
two classes of observables;
line-shape observables: MZ , ΓZ , partial widths, σpeak , . . .
Rℓ =
Γhad
Γlept
,
Rb =
EW 2-loop fermionic corrections
Γb
Γhad
[Freitas; Freitas, Y.-C. Huang]
hadronic width:
RQCD
Γhad = ΓEW
had · RQCD
α 3
α 4
α 2
αs
s
s
s
=1+
+ A3
+ A4
+ A2
π
π
π
π
[Baikov, Chetyrkin, Kühn, Rittinger]
two classes of observables;
asymmetries: AF B , ALR , . . .
⇒
forward-backward asymmetry
Af =
f
2 gVf /gA
f 2
1 + (gVf /gA
)
AF B =
⇒
σF −σB
σF +σB
=
3
4
Ae Af
f
sin2 θeff
polarized cross section for e−
L,R :
⇒
left-right asymmetry
ALR =
σL −σR
σL +σR
= Ae
asymmetries determine sin2 θeff
⇒
sin2 θeff
EW 2-loop calculations for sin2 θeff
Awramik, Czakon, Freitas, Weiglein
Awramik, Czakon, Freitas
Hollik, Meier, Uccirati
universal terms at 3- and 4-loops (EW and QCD)
van der Bij, Chetyrkin, Faisst, Jikia, Seidensticker
Faisst, Kühn Seidensticker, Veretin
Boughezal, Tausk, van der Bij
Schröder, Steinhauser
Chetyrkin, Faisst, Kühn
Boughezal, Czakon
Chetyrkin, Faisst, Kühn, Maierhofer, Sturm
0.2325
sin2 Θeff
0.232
0.2315
exp
0.231
1loop
+QCD+lead.3loop
+2loop
0.2305
200
theory uncertainty:
δ ∆α = 10−4 :
400
600
MH @GeVD
δ sin2 θeff = 5 · 10−5
δ sin2 θeff = 3.5 · 10−5
800
1000
some observables with not-so-good agreement
in general, SM is in overall agreement with data
yet a few quantities stand a bit apart (∼ 3σ )
the forward-backward asymmetry for b quarks,
b̄ at the Z peak
AbFB
the anomalous magnetic moment of the muon
the forward-backward asymmetry for top quarks
at the Tevatron, pp̄ → tt̄
new NNLO QCD calculation: Czakon, Fiedler, Mitov 2015
data now compatible with SM prediction (QCD + EW)
forward-backward asymmetry for b quarks
is around since the days of LEP/SLC
indicates presence of some extra right-handed
contributions to the Zbb coupling
no convincing explanation in current new physics
models
Afb
0,l
0.23099 ± 0.00053
Al(Pτ)
0.23159 ± 0.00041
Al(SLD)
0.23098 ± 0.00026
Afb
0,b
0.23221 ± 0.00029
0,c
Afb
had
Qfb
0.23220 ± 0.00081
0.2324 ± 0.0012
0.23153 ± 0.00016
Average
MH [GeV]
10
10
χ /d.o.f.: 11.8 / 5
2
3
2
0.23
∆α(5)
had= 0.02758 ± 0.00035
mt= 172.7 ± 2.9 GeV
0.232
lept
sin2θeff
0.234
AbFB determined by sin2 θe and sin2 θb :
AbFB =
Ae =
3
4
1−4 sin2 θe
,
1+(1−4 sin2 θe )2
Ae Ab
Ab =
1−4/3 sin2 θb
1+(1−4/3 sin2 θb )2
recent electroweak 2-loop calculation – too small
Awramik, Czakon, Freitas, Kniehl 08
-4
1×10
-2
O(mt )
-6
8×10
O(mt )
-8
O(mt )
-10
O(mt )
-5
6×10
2
sin θeff
2-loop,ferm
-4
O(mt )
-5
-5
4×10
-5
2×10
0
200
400
600
MH[GeV]
800
1000
anomalous magnetic moment of the muon
Higher order corrections are classified into 3 classes:
W
W
Z
(a)
pure QED
(b1 )
electroweak
(b2 )
(c)
hadronic
aSM aQED aEW aHad
The QED part is known to 5 loops
Kinoshita et al.
The EW part is known to 2 loops
Czarnecki, Krause, Marciano;
Gnendiger, Stöckinger, Stöckinger-Kim
The hadronic part is known with limited accuracy,
hadronic vacuum polarization from data at low energies
many authors, most recent: Jegerlehner 2015
Anomalous g-factor of the muon
incl. ISR
DHMZ10 (e+ e− )
180.2 ± 4.9
DHMZ10 (e+ e− +τ )
189.4 ± 5.4
JS11/FJ15 (e+ e− +τ )
176.4 ± 5.2
HLMNT11 (e+ e− )
182.8 ± 4.9
DHMZ10/JS11 (e+ e− +τ )
181.1 ± 4.6
BDDJ15# (e+ e− +τ )
170.4 ± 5.1
BDDJ15∗ (e+ e− +τ )
175.0 ± 5.0
excl. ISR
DHea09 (e+ e− )
178.8 ± 5.8
BDDJ12∗ (e+ e− +τ )
175.4 ± 5.3
experiment
BNL-E821 (world average)
208.9 ± 6.3
150
SM prediction:
[3.6 σ]
[2.4 σ]
[3.4 → 4.0 σ]
[3.3 σ]
[3.6 σ]
[4.8 σ]
[4.2 σ]
[3.5 σ]
[4.1 σ]
∗
HLS global fits
#
200
HLS best fit
250
aµ ×1010 -11659000
Jegerlehner 2015
4σ below exp. value
theory uncertainty from hadronic vacuum polarization
Global fit to the Higgs boson mass
before the discovery in 2012
6
mLimit = 152 GeV
March 2012
Theory uncertainty
∆α(5)
had =
5
blueband: Theory uncertainty
0.02750±0.00033
0.02749±0.00010
2
4
incl. low Q data
MH < 152 GeV (95%C.L.)
2
MH = 94+29
−24 GeV
∆χ
2
3
1
0
LEP
excluded
40
LHC
excluded
100
MH [GeV]
200
The Higgs era
2015: first combined ATLAS/CMS Higgs-boson mass determination
ATLAS and CMS
LHC Run 1
Total
Syst.
Stat.
Total
Stat.
Syst.
ATLAS H → γ γ
126.02 ± 0.51 ( ± 0.43 ± 0.27) GeV
CMS H → γ γ
124.70 ± 0.34 ( ± 0.31 ± 0.15) GeV
ATLAS H → ZZ → 4l
124.51 ± 0.52 ( ± 0.52 ± 0.04) GeV
CMS H → ZZ → 4l
125.59 ± 0.45 ( ± 0.42 ± 0.17) GeV
ATLAS +CMS γ γ
125.07 ± 0.29 ( ± 0.25 ± 0.14) GeV
ATLAS +CMS 4l
125.15 ± 0.40 ( ± 0.37 ± 0.15) GeV
ATLAS +CMS γ γ +4l
125.09 ± 0.24 ( ± 0.21 ± 0.11) GeV
123
124
125
126
127
128
129
mH [GeV]
A Standard Model Higgs boson at the LHC?
Moriond 2016
µ = 1.09+0.11
−0.10
µ = σ(pp → H) · BR(H → X)/[SMtheory ]
Higgs production at the LHC
Higgs production modes
ggF
VBF
VBF
VH
ttH
VH
•
ttH
Dominant Higgs production modes expected from the SM at m =125 GeV:
Handbook of Higgs Cross Sections, Vol. 1, 2, 3
CERN-2011-002, CERN-2012-002, CERN-2013-004
NLO exact
Dawson (1991); Djouadi, Spira, Zerwas (1991)
Graudenz, Spira, Zerwas (1993)
Heavy quarks in the loops make the computation difficult.
NNLO computed using effective vertex
Harlander, Kilgore (2002)
Anastasiou, Melnikov (2002)
Ravindran, Smith, van Neerven (2003)
Double Virtual:
⊗
⊗
+ 148 terms;
⊗
⊗
+ 635 terms;
⊗
+ 594 terms.
Real Virtual:
Double Real:
⊗
In addition:
q + g → h + X(q, q, g)
qi + qj (q j ) → h + X(q, q, g)
NNNLO for gg → H
Anastasiou et al. 2015
Consistent with previous NNLL+NNLO
!"#$% &' ()*' &+ *",
*%
!"
#!"
)%
pure EFT symm
scale variation
LO:
at
N3LO ~2%14.8
NLO:
16.6
NNLO: 8.8
N3LO: 1.8
##!"
(%
!"#
!!""
#$!"
'%
%
%&%
%&'
%&(
%&)
!!! " #
%&*
+&%
+&'
"# # $
‣ + more accurate pdfs (PDF4LHC prescription)
H → V V → 4f
decays:
needs also background pocesses + h.o.
fa
V
H
fa
f¯b
f¯b
V
V
H
fc
V
fa
fc
V
f¯b
fc
fb
V
H
f¯b
V
fc
fa
fa
f¯b
f¯b
H
fc
H
V
fc
fa
f¯d
f¯d
V
f¯b
f¯d
fa
f¯d
fa
fc
H
fc
f¯b
V
f¯d
V
fd
H
fc
fa
V
f¯d
H
V
fa
f¯b
H
fc
f¯d
V
f¯b
V
H
fc
V
fa
f¯b
V
H
f¯d
V
fa
f¯d
fa
H
f¯b
fc
fc
f¯d
f¯d
f¯d
Bredenstein, Denner, Dittmaier, Weber 2007
PROPHECY4f
H → γγ
decays:
γ
H
γ
H
γ
(a)
(b)
γ
H
(c)
γ
γ
γ
H
γ
H
γ
(d)
(e)
γ
H
q
t
(f)
γ
H
q
t
(g)
γ
γ
γ
non-singlet and singlet terms; electroweak corrections (Passarino,. . .)
ΓH→γγ = (9.398 −
0.148
LO×NLO-EW
+
0.168
LO×NLO-QCD
+ 0.00793) keV
α2s
α2s term dominated by singlet part of prediction,
prediction good to 1 permille!
Maierhöfer, Marquard 2012
precision physics in the Higgs era
Higgs boson mass MH is now an additional precise
input parameter
partial decay widths influenced by quantum effects
– accordingly, affected also by non-standard physics
– new set of sensitive precision observables
MH itself is a prediction/ precision observable in
specific classes of models
further empirical information available on top of the
“classical” set of precision observables
production of tt̄H
measurement of the Higgs–top Yukawa coupling
Idea under discussion: highly boosted “fat jets”
b̄
b
b̄
t
t
H
H
t̄
W−
p
l
ν̄l
p
W+
t
t
q̄ ′
t̄
q
b
Butterworth et al. ʼ08; ATL-PHYS-PUB-2009-088
fat jet containing
pair from high-
Higgs
(successful in WH/ZH revival!)
requires accurate background calculations, e.g.
for pp → tt̄ bb̄
µR = µF = ξmt
.... LO
— NLO
Bredenstein et al.
Bevilacqua et al.
Main results:
measurement of Higgs self-coupling
HH production channels
gg fusion
→
H
g
H
g
g
H
VV fusion
q
q′
V
q
V∗
10
4
10
3
10
2
Q
∗
HH production at pp colliders at NLO in QCD
MH=125 GeV, MSTW2008 NLO pdf (68%cl)
H
→
′
H
H
σNLO[fb]
Q
H
H (EF
pp→H
)
roved
p-imp
T loo
101
F)
B
Hjj (V
pp→H
H
H
tt
pp→
100
10
H
pp→WH
MadGraph5_aMC@NLO
g
H
pp→ZH
-1
tj
pp→
q
HH
10-2
Associated production with top
10-3
8
1314
25
33
50
75
100
√s[TeV]
t
g
q̄
H
H
g
t̄
g
q
Higgs-strahlung
→
q̄ ′
q
V∗
H
H
V
√
s [TeV]
NLO
σgg→HH
[fb]
NLO
σqq
′ →HHqq ′ [fb]
σqNNLO
q̄ ′ →W HH [fb]
σqNNLO
q̄→ZHH [fb]
σqLO
q̄/gg→tt̄HH [fb]
0.21
8
8.16
0.49
0.21
0.14
14
33.89
2.01
0.57
0.42
1.02
33
207.29
12.05
1.99
1.68
7.91
100
1417.83
79.55
8.00
8.27
77.82
Gluon-gluon fusion dominates
Only some contribute with HHH
production of VV + 2 jets
measure V V → V V scattering
sensitive to electroweak symmetry breaking – BSM?
V
H
e.g.
V′
background for Higgs production via vectorboson fusion
with H → V V
q
W, Z
H
W, Z
q
Status of the Standard Model
e
Myon
Tauon
511 keV
105.6 MeV
1777 MeV
u
c
t
Up-Quark
2 MeV
Charm-Quark
1.5 GeV
Top-Quark
173.1 GeV
d
s
b
Down-Quark
5 MeV
Strange-Quark
150 MeV
Bottom-Quark
4.5 GeV
W
Z
g
Photon
W-Boson
Z-Boson
Gluon
0
80.40 GeV
91.1875 GeV
0
H
Higgs-Boson
125 GeV
Quarks
Elektron
9
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Bosons
e
< 18 MeV
Fermions
Tau-Neutrino
< 190 keV
(force particles)
Myon-Neutrino
9
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;
(matter particles)
Elek.-Neutrino
< 3 eV
Leptons
9
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9
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SM input completey determined
precision observables
⇒
exp
sin2 θeff
0.23152 ± 0.00005 ± 0.00005
0.23153 ± 0.00016
MW (GeV)
80.361 ± 0.006 ± 0.004
80.385 ± 0.015
MW [GeV]
theo
80.5
mkin
t Tevatron average ! 1
68% and 95% CL fit contours
w/o MW and mt measurements
80.45
80.4
68% and 95% CL fit contours
w/o MW , mt and MH measurements
MW world average ! 1
80.35
80.3
140
0
=5
MH
V
Ge
.7
25
=1
00
=3
MH
MH
150
160
V
Ge
0
60
V
Ge
G fitter SM
=
MH
170
180
190
Sep 12
80.25
200
mt [GeV]
evolution of self-coupling λ with scale Q
dλ
1
2
4
2
Q
12λ − 3 gt + 6 λ gt + · · ·
=
2
2
dQ
16π
2
vacuum stability:
λ(Q) > 0
Hambye, Riesselmann 1997
up to scale Λ
evolution of self-coupling λ with scale Q
dλ
1
2
4
2
Q
12λ − 3 gt + 6 λ gt + · · ·
=
2
2
dQ
16π
2
vacuum stability:
λ(Q) > 0
up to scale Λ
1018
1Σ bands in
Mt = 173.1 ± 0.6 GeV
Αs HMZ L = 0.1184 ± 0.0007
Mh = 125.66 ± 0.34 GeV
Instability scale in GeV
1016
1014
1012
1010
108
115
120
125
130
135
Higgs mass Mh in GeV
Hambye, Riesselmann 1997
Degrassi et al. 2012
180
ility
150
M
ab
-s t
eta
100
Stability
50
0
0
50
100
150
Higgs mass Mh in GeV
200
Pole top mass Mt in GeV
Instability
Non-perturbativity
Top mass Mt in GeV
200
107
1010
Instability
Instability
Meta-stability
175
1,2,3 Σ
170
10
1012
165
115
Stability
120
125
Higgs mass Mh in GeV
[Degrassi et al. 2012]
precise measurement of mt crucial input
130
135
Present uncertainties
20
Prospects for LHC
80.44
4σ
Prospects for ILC/GigaZ (δ theo = Gauss)
3σ
mt ± 1σ
G fitter SM
Prospects for LHC
Prospects for ILC/GigaZ
80.4
80.38
10
68% and 95% CL fit contours
w/o MW and mt measurements
Present SM fit
80.42
Prospects for ILC/GigaZ (δ theo = Rfit)
15
80.46
Oct 13
G fitter SM
Present SM fit
MW [GeV]
5σ
25
Oct 13
∆ χ2
the future of SM tests
80.36
Present measurement
ILC precision
LHC precision
MW ± 1σ
80.34
5
2σ
80.32
0
1σ
60
80
100
120
140
160
180
200
80.3
160
165
170
175
180
MH [GeV]
from: Working Group Report of the 2013 Community Summer Study (Snowmass)
on the Energy Frontier Precision Study of Electroweak Interactions
185
mt [GeV]
present and aimed experimental precision
exp. error
LEP/Tev/LHC
LC/GigaZ
FCee
MZ [MeV]
2.1
2.1
0.1
MW [MeV]
10
3-5
1
sin2 θeff [10−5 ]
17
1.3
0.6
Rb [10−5 ]
66
15
5
mtop [GeV]
0.7
0.1
0.05
∆α
1 · 10−4
5 · 10−5
< 5 · 10−5
αs
6 · 10−4
< 6 · 10−4
1 · 10−4
0.2330
experimental errors 68% CL / collider experiment:
LEP/SLD/Tevatron
0.2325
LHC
ILC/GigaZ
AFB (LEP)
mt = 170 .. 175 GeV
sin
2
eff
0.2320
0.2315 SM:MH = 125.6 ± 0.7 GeV
0.2310
ALR (SLD)
0.2305
MSSM
SM, MSSM
0.2300
80.2
80.3
Heinemeyer, Hollik, Weiglein, Zeune et al. ’13
80.4
MW [GeV]
80.5
80.6
80.60
experimental errors 68% CL / collider experiment:
LEP2/Tevatron: today
LHC
ILC/GigaZ
80.50
Mh = 125.6 ± 3.1 GeV
MW [GeV]
MSSM
80.40
80.30
SM MH = 125.6 ± 0.7 GeV
MSSM
SM, MSSM
Heinemeyer, Hollik, Stockinger, Weiglein, Zeune ’13
168
170
172
174
mt [GeV]
176
178
Conclusions and perspectives
impressive confirmation by a huge data sample from low to
high energies, no significant deviations
quantum effects have been established at many σ
perfect indirect and direct determination of the top quark
now repeated for the Higgs boson
scalar particle at 125 GeV: SM Higgs boson
or first signal of BSM?
next steps with upgraded LHC / improved precison
– confirm the Higgs boson properties
– check versus electroweak precision measurements
– or find deviations, new structures