standard model physics results from lep2
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Standard Model Physics
Results from LEP2
Stephan Wynhoff
CERN
on behalf of the LEP collaborations
Aleph, Delphi, L3, Opal
5th International Symposium on Radiative CorrectionsCarmel, USA
11.-15. September 2000
• Fermion Pair Production
Cross sections and Asymmetries
S-matrix
Contact interactions
• Boson Cross Sections
ZZ Production
Single W Production
• W+W−Production
Cross Section
Branching Fractions
• W Mass Measurement
Mass extraction
Systematic Errors
Comparison of Direct and Indirect Results
• Standard Model Fits
Stephan Wynhoff Standard Model Physics Results from LEP2 2
10-4
10-3
10-2
10-1
1
10
80 100 120 140 160 180 200 220s /GeV
σ/nb
88 90 92 940
10
20
30
1990-19921993-19951996-19981999-2000 (prel.)
mH=114 GeV
e+e– → hadrons
e+e– → HZ → qq_qq
_
e+e–→ W+W−
→ qq_qq
_
e+e–→ ZZ→ qq
_qq
_
L3
• large data statistics at the Z pole:
15 million hadronic and 2 million leptonic events
• above the Z resonance:
luminosity 590 – 630 pb−1 per experiment
• more than 8000 W-pair events per experiment
Stephan Wynhoff Standard Model Physics Results from LEP2 3
See LEP2MC workshop proceedingshep-ph/0005309, hep-ph/0007180
2-Fermion Processes
• ZFITTER, KKMCbetter than 0.2% precision in σtot of hadrons, leptons
• KKMC covers LEP, LC, µ-colliders, τ - and b-factories.
4-Fermion Processes
• RacoonWW, YFSWW3σ(W+W−) to 0.4%. (double-pole approx. above thresh-old.)
• WPHACT, grc4f, WTO, ...σ(Weν) to 4-5%. (fermion loop scheme.)
• YFSZZ, ZZTOσ(ZZ) to 2%.
⇓
Excellent match in precision
Experiment ⇐⇒ Theory
Stephan Wynhoff Standard Model Physics Results from LEP2 4
e−
e+
f
f
PP
ISR
FSR
• Initial State Radiation
• Pair Production:
• Final State Radiation
√s′:= mass of outgoing lepton pair or γ∗/Z propagator
→ high energy events:√
s′ > 0.85√
s
10 2
10 3
50 100 150 2001
10
10 2
10 3
10 4
50 100 150 200
0
20
40
60
80
100
120
140
160
180
50 100 150 2000
20
40
60
80
100
120
50 100 150 200
√s′ /GeV
Eve
nts
→
√s′ /GeV
Eve
nts
√s′ /GeV
Eve
nts
→
√s′ /GeV
Eve
nts
→
OPAL 205.4 GeV preliminary
(a) hadrons (b) e+e-
(c) µ+µ- (d) τ+τ-
Stephan Wynhoff Standard Model Physics Results from LEP2 5
Cro
ss s
ectio
n (p
b)√s
´/s
> 0.85
e+e−→hadrons(γ)e+e−→µ+µ−(γ)e+e−→τ+τ−(γ)
LEPpreliminary
√s
(GeV)
σ mea
s/σ S
M
1
10
10 2
0.8
0.9
1
1.1
1.2
120 140 160 180 200 220
Stephan Wynhoff Standard Model Physics Results from LEP2 6
Differential cross sections for Muon-, Tau-pair production
Preliminary LEP Averaged dσ/dcosθ (µµ)183 GeV
cosθf
dσ/d
cosθ
(pb
)
189 GeV
cosθf
dσ/d
cosθ
(pb
)
192 GeV
cosθf
dσ/d
cosθ
(pb
)
196 GeV
cosθf
dσ/d
cosθ
(pb
)
200 GeV
cosθf
dσ/d
cosθ
(pb
)
202 GeV
cosθf
dσ/d
cosθ
(pb
)
0
2
4
-1 -0.5 0 0.5 10
1
2
3
4
-1 -0.5 0 0.5 1
0
1
2
3
4
-1 -0.5 0 0.5 10
1
2
3
4
-1 -0.5 0 0.5 1
0
1
2
3
4
-1 -0.5 0 0.5 10
1
2
3
-1 -0.5 0 0.5 1
Use for limits on
• Contact interactions
• Fermion size
• Extra dimensions, TeV strings, gravitons
Stephan Wynhoff Standard Model Physics Results from LEP2 7
For
war
d-B
ackw
ard
Asy
mm
etry √s
´/s
> 0.85
e+e−→µ+µ−(γ)e+e−→τ+τ−(γ)
LEPpreliminary
√s
(GeV)
AF
B
mea
s -AF
B
SM
0
0.2
0.4
0.6
0.8
1
-0.2
0
0.2
120 140 160 180 200 220
Stephan Wynhoff Standard Model Physics Results from LEP2 8
Fermion Pair - Heavy Flavours
s (again) the ratio of cross sections
0.14
0.16
0.18
0.2
0.22
0.24
0.26
80 100 120 140 160 180 200√s (GeV)
Rb
Rb
LEP preliminary
√s’/√s > 0.1 , 0.85
0.14
0.16
0.18
0.2
0.22
0.24
0.26
0.28
0.3
0.32
80 100 120 140 160 180 200√s (GeV)
Rc
Rc
LEP preliminary
√s’/√s > 0.1 , 0.85
-0.2
0
0.2
0.4
0.6
0.8
1
80 100 120 140 160 180 200√s (GeV)
b-A
sym
met
ry
Ab FB
LEP preliminary
√s’/√s > 0.1 , 0.85
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
80 100 120 140 160 180 200√s (GeV)
c-A
sym
met
ry
Ac FB
LEP preliminary
√s’/√s > 0.1 , 0.85
Stephan Wynhoff Standard Model Physics Results from LEP2 9
• Measure Interference between γ and Z (jhad)
-4
-3
-2
-1
0
1
2
3
4
50 75 100 125 150 175 200
s [GeV]
σ int/σ
tot [
%]
no cuts'/s > 0.85
σ0a(s) =
4
3πα2
gafs
+jaf(s−m2
Z) + raf s
(s−m2Z)
2 +m2ZΓ
2Z
, for a = tot, fb,
A0fb(s) =
3
4
σ0fb(s)
σ0tot(s)
, with σ0fb =
4
3(σf − σb) .
• Photon exchange
• Z-Boson exchange
• γ/Z interference
“Standard” fits: fix gaf and jaf ZFITTER, TOPAZ0
S-Matrix fits: fix gaf only ZFITTER, SMATASY
Stephan Wynhoff Standard Model Physics Results from LEP2 10
-0.5
0
0.5
1
1.5
91.17 91.18 91.19 91.2mZ [GeV]
j had
tot
68% CL
SM
L3 Z dataL3 data ≤ 189 GeVLEP + Tristan (potential)
MZ[MeV] jtothad corr.
L3 Z data 91 185.2±10.3 0.44±0.59 -0.95L3 ≤ 189GeV 91 187.5±3.9 0.31±0.13 -0.57LEP + Tristan: ±2.3 ±0.04 -0.28
Stephan Wynhoff Standard Model Physics Results from LEP2 11
L =1
1 + δef
∑i,j=L,R
ηijg2
Λ2ij
(eiγµei)(fjγµfj),
e+
e−
l+, q−
l−, q
g2 / Λ2
g Coupling, byconvention g2/4π = 1
ηij Helicity amplitudes,choose |ηij| = 0, 1
Λ Energy scale
dσ
d cos θ=
dσSM
d cos θ+ cint(s, cos θ)
1
Λ2+ cci(s, cos θ)
1
Λ4.
ηRR ηLL ηLR ηRLAA ±1 ±1 ∓1 ∓1VV ±1 ±1 ±1 ±1RR ±1 0 0 0LL 0 ±1 0 0
LEP Preliminary 130-202 GeV
Λ- (TeV) Λ+ (TeV)
LL 10.2 12.8
RR 9.7 12.3
VV 17.2 20.4
AA 13.9 17.6
Λ- Λ+
20. 0 20.
Stephan Wynhoff Standard Model Physics Results from LEP2 12
Z
Z
e−
e+
f
f
f'
f'
Z
Z
e−
e+
f
f
f'
f'
0
0.5
1
1.5
170 180 190 200
Ecm [GeV]
σZZ
NC
02 [p
b]
LEP Summer 00 - Preliminary20/07/2000
±2.0% uncertainty
ZZTO
YFSZZ
Stephan Wynhoff Standard Model Physics Results from LEP2 13
e+ e+
γ
W
Q2→0
e− νe
WMW
2s
f– ‘
f
0
0.5
1
160 170 180 190 200 210
Ecm [GeV]
σ(e+
e– → e
νW)
[pb]
LEP Preliminary21/07/2000
±5.0% uncertainty
grc4fWPHACT IFL/α(t)
W → ff-’
Stephan Wynhoff Standard Model Physics Results from LEP2 14
• W-pair production at LEP
e– W–
f
f´νe
W+
f
f´
e+
e–
e+γ,Z
W–
f
f´
W+ f
f´
SM branchings Br(W → qq′) = 67.6%Br(W → lν) = 10.8% per lepton flavour
D E L P H I R u n : E v t :
B e a m :
DA S :
P r o c :
S c a n :
1 0 4 . 4 Ge V 2 9 - Ap r - 2 0 0 0
2 9 - Ap r - 2 0 0 0
1 1 : 4 3 : 3 4
2 9 - Ap r - 2 0 0 0
109372 8483
T a n a g r a
• Fully hadronic: 45.6% 4 jets
High Multiplicity, balanced events
Y
XZ
• Semileptonic: 3×14.6% 2 jets, 1 lepton
Hadronic energy plus high energy lepton ornarrow jet (τ )
OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
OOOOO
OOOO
OOOOOO
OOOOOOOOOOOOO
OOOOOOOO
OOOOO
OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
OOOOO
OOOO
OOOOOO
OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
OOOOO
OOOO
OOOOOO
OOOOOOOOOOOOO
OOOOOOOO
OOOOO
OO
OO
OO
OO
OO
OO
OO
OO++++
• Fully leptonic: 10.6% 2 leptons
Low multiplicity, acoplanar, missing energy
Stephan Wynhoff Standard Model Physics Results from LEP2 15
0
5
10
15
20
160 170 180 190 200 210
Ecm [GeV]
σWW
[pb]
LEP Preliminary21/07/2000
Gentle 2.1 (±0.7%)
RacoonWW / YFSWW 1.14
0
5
10
15
20
160 170 180 190 200 2100
5
10
15
20
160 170 180 190 200 210
RacoonWWYFSWW 1.14
16
17
18
Excellent agreement with
• RacoonWW• YFSWW
at Ecm > 170 GeV
Stephan Wynhoff Standard Model Physics Results from LEP2 16
21/07/2000
Br(W→hadrons) [%]
ALEPH 67.22 ± 0.53
DELPHI 67.81 ± 0.61
L3 68.47 ± 0.59
OPAL 67.86 ± 0.62
LEP 67.78 ± 0.32
66 68 70
Br(W→hadrons) [%]
Summer 00 - Preliminary - [161-207] GeV
DELPHI [161-202] GeV
L3 [161-202] GeV
Stephan Wynhoff Standard Model Physics Results from LEP2 17
• Indirect determination of |Vcs|:Br(W → hadrons)
1 −Br(W → hadrons)=
∑ ∣∣∣∣∣V2ij
∣∣∣∣∣
1 +
αs
π
• Direct determination of |Vcs| from tagged charm:
OPAL :Γ(W → cX)
Γ(W → had)= 0.47 ± 0.04 ± 0.06
LEP |Vcs|Indirect 0.989 ± 0.016
Direct 0.95 ± 0.08
Stephan Wynhoff Standard Model Physics Results from LEP2 18
21/07/2000
W Leptonic Branching Ratios
ALEPH 11.19 ± 0.34DELPHI 10.33 ± 0.45L3 10.22 ± 0.36OPAL 10.52 ± 0.37
LEP W→eν 10.62 ± 0.20
ALEPH 11.05 ± 0.32DELPHI 10.68 ± 0.34L3 9.87 ± 0.38OPAL 10.56 ± 0.35
LEP W→µν 10.60 ± 0.18
ALEPH 10.53 ± 0.42DELPHI 11.28 ± 0.56L3 11.64 ± 0.51OPAL 10.69 ± 0.49
LEP W→τν 11.07 ± 0.25
LEP W→lν 10.74 ± 0.10
10 11 12
Br(W→lν) [%]
Summer 00 - Preliminary - [161-207] GeV
DELPHI [161-202] GeV
L3 [161-202] GeV
Indirect extraction from TEVATRON:
Br(W → eν) [%]
CDF 10.50 ± 0.30
D0 10.39 ± 0.35
10.43 ± 0.25
Stephan Wynhoff Standard Model Physics Results from LEP2 19
q1
q2
e,µ,τ
ν
q2q1
q4q3
• reconstruct lepton and jets
• impose kinematic constraints:
E and *p conservation → 1C for qq+ν, 4C for qqqqequal masses of recontructed W’s → +1C
• special for qqqq events: jet pairing problem
q2q1
q4q3
q2q1
q4q3
q2q1
q4q3
→ choose best pairing
• also gluon radiation is taken into account→ split into 4 and 5 jet sample (D,O)
Stephan Wynhoff Standard Model Physics Results from LEP2 20
L3
minv [GeV]
Num
ber o
f Eve
nts
/ 1 G
eV1999 Data qqeνM.C. reweighted
M.C. background (a)
preliminary
MW = 80.28 ± 0.19 GeV
0
20
40
60
60 70 80 90 1000
10
20
30
40
50
60
70
80
90
100
50 55 60 65 70 75 80 85 90 95
MW (GeV/c2)
Eve
nts
per
1 G
eV/c
2
ALEPH Preliminaryµνqq selection
√s = 191.6,195.5,199.5,201.6 GeV
Data (Luminosity = 237 pb-1)
MC (mW = 80.60 GeV/c2)
Non-WW background
DELPHI preliminary
0
10
20
30
40
50
60
70
80
90
50 55 60 65 70 75 80 85 90 95 100
W mass (GeV/c2)
even
ts /
2 G
eV/c
2
0
50
100
150
200
70 80 90m / GeV
Ev
ents
/ G
eV qqqq 4-jet
OPAL 192-202 GeV preliminary
→ compare reweighted Monte Carlo to data (A,L,O)→ convolute differential cross-section with resolution
function (D,O)→ fit Breit-Wigner curve to measured mass spectrum (O)
Stephan Wynhoff Standard Model Physics Results from LEP2 21
• all LEP2 data until 1999 included:
80 80.2 80.4 80.6 80.8 81
MW [GeV]
preliminary
80 80.2 80.4 80.6 80.8 81
ALEPH
DELPHI
L3
OPAL
LEP
80.440 ± 0.064 GeV
80.380 ± 0.071 GeV
80.375 ± 0.077 GeV
80.485 ± 0.065 GeV
80.427 ± 0.046 GeV
χ2/dof = 27.1/29
• LEP value is a combination of individual measurementsfrom the experiments for different channels and years
• contribution to total error from
statistics: 30 MeVsystematics: 36 MeV
Stephan Wynhoff Standard Model Physics Results from LEP2 22
• LEP energy error ∆Ebeam = 21 MeV
⇒ ∆MW = ∆EbeamEbeam
· MW = 17 MeV
• new LEP spectrometer → precision ∆Ebeam < 15 MeV(not yet achieved)
• Final State Interactions in qqqq events
γ,Z
W–
W+
πo πo
K+ K+
π– π–
ColourReconnection
Bose-Einstein
• cross-talk affects reconstruction of invariant masses
Stephan Wynhoff Standard Model Physics Results from LEP2 23
Identical pions close in phase space:Q2 = squared 4-momentum difference
Q [GeV]
R2
WW qqlv data - 189 GeV•
Z→light quark data - 91 GeV¬
L3 preliminary
0.8
1
1.2
1.4
1.6
1.8
2
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Intra-W effects:
W± � Zdecays (Z �→ bb)
Cross talk in W+W− → qqqq ?
Q [GeV]
D, (±
,±)/
0.04
GeV
L3 data
inter-W correlation
no inter-W correlation
p < 1.5 GeVL3
0.80.9
11.11.21.31.41.5
0 0.2 0.4 0.6 0.8 1 1.2 1.4
→ BE correlations only inside each W!?
Stephan Wynhoff Standard Model Physics Results from LEP2 24
Compare particle flow between jets from
C
D
A
B
• same (A,C)
• different (B,D)
W-Boson
0
2
4
6
0 50 100 150 200 250 300 350particle flowparticle flowparticle flowparticle flowparticle flow φ
1/N
evt d
σ/dφ
ALEPHpreliminary
particle flow
data (@ 189 GeV)WWZZqqγ
0
2
4
6
0 0.5 1 1.5 2 2.5 3 3.5 4norm. particle flownorm. particle flownorm. particle flownorm. particle flownorm. particle flow φr
1/N
evt d
σ/dφ
r
norm. particle flow
data (@ 189 GeV)WWZZqqγ
W-jets W-jets
ALEPHpreliminary
A B C D
0.75
1
1.25
1.5
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1φr
1/N
evt d
σ/dφ
r(A
+C)/
(B+D
)
ALEPH preliminary
data 189, 196, 200 GeV combined
KoralW, ki = 0.
KoralW, ki = 0.6
KoralW, ki = 2.3
KoralW, ki = 1000. L3, ALEPH:
R =dn/dφ(A+ C)
dn/dφ(B +D)
→ not yet statistically significant, but promising
Stephan Wynhoff Standard Model Physics Results from LEP2 25
• ∆MW = mqqqq −mqqlν probes possible effects of FSI
-0.5 0 0.5
∆MW [GeV]
preliminary
-0.5 0 0.5
ALEPH
DELPHI
L3
OPAL
LEP
0.032 ± 0.091 GeV
−0.011 ± 0.112 GeV
0.190 ± 0.130 GeV
−0.103 ± 0.111 GeV
0.005 ± 0.051 GeV
FSI 0.056 GeV
→ no indication for mass shift due to FSI
• FSI systematic error is estimated by comparingMC models
for BE → with and w/o cross-talkfor CR → SK I, SK II, SK II’, ARIADNE I and II,
HERWIG, GH
all experiments are affected in the same way!
• error on qqqq due to BE: 25 MeV CR: 50 MeV
statistical error component: 34 MeV (qqqq only)
Stephan Wynhoff Standard Model Physics Results from LEP2 26
typical example
Source Systematic Errors on MW in MeVqq+ν qqqq Combined
Colour Reconnection – 50 13Bose-Einstein Correlations – 25 7LEP Beam Energy 17 17 17ISR / FSR 8 10 8Hadronisation 26 23 24Detector Systematics 11 8 10Other 5 5 4Total Systematic 35 64 36Statistical 38 34 30Total 51 73 47
• due to FSI → contribution to combined MW measurement:
qqqq 27% and qq+ν 73%
Stephan Wynhoff Standard Model Physics Results from LEP2 27
• comparison with other W mass measurements:
W-Boson Mass [GeV]
mW [GeV]
χ2/DoF: 0.1 / 1
80 80.2 80.4 80.6
pp−-colliders 80.452 ± 0.062
LEP2 80.427 ± 0.046
Average 80.436 ± 0.037
NuTeV/CCFR 80.25 ± 0.11
LEP1/SLD/νN/mt 80.386 ± 0.025
Stephan Wynhoff Standard Model Physics Results from LEP2 28
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4 2.51.5 2.0 2.5ΓW[GeV]
ALEPH 2.17±0.20
DELPHI 2.09±0.15
L3 2.19±0.21
OPAL 2.04±0.18
LEP 2.12±0.11
LEP Preliminary : Summer 2000
• compare direct width determination by CDF
ΓW = 2.06 ± 0.13 GeV
Stephan Wynhoff Standard Model Physics Results from LEP2 29
10
10 2
10 3
80.25 80.5mW [GeV]
mH [G
eV]
W-Boson Mass [GeV]ALEPH
DELPHI
L3
OPAL
LEPpp
Average
80.440±0.064
80.380±0.071
80.375±0.077
80.485±0.065
80.427±0.04680.451±0.062
80.436±0.037
mt =174.3±5.1 GeV
∆α(5)
had =0.02755±0.00046
Stephan Wynhoff Standard Model Physics Results from LEP2 30
• compare direct MW and M t with fit to electroweak data:
80.2
80.3
80.4
80.5
80.6
130 150 170 190 210
mH [GeV]113 300 1000
mt [GeV]
mW
[G
eV]
Preliminary
68% CL
LEP1, SLD, νN Data
LEP2, pp− Data
• from electroweak fitswith LEP data: M t = 179+13
−10 GeVall data except direct MW: MW = 80.386 ± 0.025 GeV
Standard Model parameter relationsconfirmed at 1-loop level W W
b
t
Stephan Wynhoff Standard Model Physics Results from LEP2 31
•α(M2Z) is important ingredient in EW fits → M H
• running of α:
α(s) =α(0)
1 − ∆αlep(s) − ∆α(5)had(s) − ∆αtop
had(s)• ∆αlep(s) known to 3-loop level
• important is contribution from ∆α(5)had
→ less precise
∆α(5)had(s) ∝
∞∫
4M2π
R(s′) ds′
s′(s′ − s)
γ
q
q
γ
• the ratio R = σ(e+e− → hadrons)/σ(e+e− → µ+µ−)
can be measured and calculated in perturbative QCD• recent measurements by BES II are now included:
BES-II (preliminary 1999)
BES-II (1998)
MK1 normalised to pQCD
γγ2
MEA
RpQCD
√ s (GeV)
Sum of exclusive channels→
← Inclusive data {
0
0.5
1
1.5
2
2.5
3
3.5
4
1 1.25 1.5 1.75 2 2.25 2.5 2.75 3 3.25
Stephan Wynhoff Standard Model Physics Results from LEP2 32
Mass of the Higgs Boson
0
2
4
6
10 102
103
mH [GeV]
∆χ2
Excluded Preliminary
∆αhad =∆α(5)
0.02804±0.00065
0.02755±0.00046
theory uncertainty
∆α(5)had M H log(M H/ GeV) M H limit
[ GeV] (95% C.L.)
0.02804 ± 0.00065 60+52−29 1.78+0.27
−0.28 < 162 GeV
new BES included0.02755 ± 0.00046 88+60
−37 1.94+0.22−0.24 < 203 GeV
new BES and pQCD0.02738 ± 0.00020 104+59
−39 2.02+0.19−0.20 < 215 GeV
(Jegerlehner et al., Pietrzyk et al., Martin et al., includes new results on MW by Tevatronand on heavy flavours by SLD)
• the new values of ∆α(5)had yield
→ a better error on log(M H/ GeV)
→ a better agreement with Higgs searches at LEP
• the Higgs boson is light . . . but heavier than
M H > 112.3 GeV at 95% CL (limit from direct searches at LEP)
Stephan Wynhoff Standard Model Physics Results from LEP2 33
• Measurement of Fermion Pair Production in good agree-ment with Standard Model predictions
• Further improvement on MZ, jhad within S-Matrix ansatz
• No new (contact) interactions below 10-20 TeV
• Cross sections for Single W, W+W−, ZZ agree as well
• LEP measures W mass and width with increased precision
MW = 80.427 ± 0.046 GeVΓW = 2.12 ± 0.11 GeV
. . . in perfect agreement with fit to electroweak data
• outlook on LEP MW:
with 2000 data → statistical error × 0.85→ δMW = 30 − 40 MeV
• there is progress going on in α(M2Z) determination
• although we are always looking for deviations . . .
The Standard Model works
The Standard Model Higgs boson is light(and maybe already observed?)
Stephan Wynhoff Standard Model Physics Results from LEP2 34
133 - 202 GeV
0.6
0.65
0.7
0.75
0.8
0.85
0.9
-0.04 -0.02 0 0.02 0.04 0.06 0.08jb
tot
j b fb
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2
-0.3 -0.2 -0.1 0 0.1 0.2 0.3jc tot
j c fb
Stephan Wynhoff Standard Model Physics Results from LEP2
133 - 202 GeV
Stephan Wynhoff Standard Model Physics Results from LEP2
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