< ↑ ↓ >
WW scattering studies at a Future Linear Collider
A presentation given at the University of Edinburgh - High Energy Physics Group.
Andres F. Osorio-Oliveros
High Energy Physics Group
The University of Manchester
Andres Osorio - Edinburgh, 14/10/2005 – p.1
< ↑ ↓ >
Outline
Motivations- Physics (why WW scattering?)- Why a FLC?
Plans for a Future Linear Collider
WW Scattering Analysis
Z and W reconstruction
Results
Sensitivities
Conclusions
Andres Osorio - Edinburgh, 14/10/2005 – p.2
< ↑ ↓ >
Motivations
The mechanism describing how Naturegives mass to particles remains one of theopen questions in particle physics today.
The Higgs Mechanism is the answer in theStandard Model
If there is no a Higgs, new physics isneeded at the TeV scale to restore unitarity
It is in this context, that the strong scatteringof WLWL bosons provides a window tolook for information about the underlyingsymmetry.
WL
WL
WL
WL
Andres Osorio - Edinburgh, 14/10/2005 – p.3
< ↑ ↓ >
Motivations
The mechanism describing how Naturegives mass to particles remains one of theopen questions in particle physics today.
The Higgs Mechanism is the answer in theStandard Model
If there is no a Higgs, new physics isneeded at the TeV scale to restore unitarity
It is in this context, that the strong scatteringof WLWL bosons provides a window tolook for information about the underlyingsymmetry.
WL
WL
WL
WL
The EW can be described by the EW ChiralLagrangian.
This is an effective theory which:- has operators of higher dimensions- introduces anomalous couplings
In particular there are two 4D operators:L4 = α4
16π2 tr(VµVν)tr(V µV ν)
L5 = α5
16π2 tr(VµV µ)tr(VνV ν)
The coefficients α4 and α5 are related tothe scale of the new physics ( in the SMthese parameters are 0)
Andres Osorio - Edinburgh, 14/10/2005 – p.3
< ↑ ↓ >
Motivations
From WW scattering studies at LHC(Butterworth,et.al-Phys.Rev.D65:096014):- EW Chiral Lagrangian- Unitarisation protocols⊲ Prediction of resonances depending onthe values of the α4 and α5 parameters
As an example:�4 = 0:000 , �5 = 0:003 (arXiv hep-ph: 0201098)
To sum up:
What’s the sensitivity to the α4 and α5 thatcan be reached at a Future Linear Collider?Can I improve previous analysis on thesubject?(Ref: Chierici, et al - LC-PHSM-2001-038)
Given that these parameters can bemeasured, what can we learn about newphysics at higher energies?( LHC - LC complementarity )
Andres Osorio - Edinburgh, 14/10/2005 – p.4
< ↑ ↓ >
Motivations
The LC scenario
Andres Osorio - Edinburgh, 14/10/2005 – p.5
< ↑ ↓ >
Motivations
The LC scenario The LHC scenario
Andres Osorio - Edinburgh, 14/10/2005 – p.5
< ↑ ↓ >
A Future Linear Collider
A global collaboration and project (ILC home page http://www.linearcollider.org)
electron sources(HEP and x-ray laser)
linea
rac
cele
rato
rlin
ear
acce
lera
tor
x-ray laser
electron-positron collisionhigh energy physics experiments
positron source
aux. positron and2nd electron source
damping ring
damping ring
positronpreaccelerator
e-
e+
e-
H.Weise 3/2000
33 k
m
Andres Osorio - Edinburgh, 14/10/2005 – p.6
< ↑ ↓ >
WW Scattering Analysis
Signal consists of the following processes:
e+e− → νν̄W+W− → νν̄qq̄qq̄
e+e− → νν̄ZZ → νν̄qq̄qq̄
e-
e+
νe
νe
W-
W+
W-/Z
W+/Z
Scenario: α4 = α5 = 0.0 (SM) Higgs → ∞
Backgrounds:e+e− → νν̄qq̄qq̄ (non-res.)e+e− → e+e−W+W−
e+e− → e+νW−Z
e+e− → W+W−(ZZ)
e+e− → qq̄
Andres Osorio - Edinburgh, 14/10/2005 – p.7
< ↑ ↓ >
WW Scattering Analysis
Signal consists of the following processes:
e+e− → νν̄W+W− → νν̄qq̄qq̄
e+e− → νν̄ZZ → νν̄qq̄qq̄
e-
e+
νe
νe
W-
W+
W-/Z
W+/Z
Scenario: α4 = α5 = 0.0 (SM) Higgs → ∞
Backgrounds:e+e− → νν̄qq̄qq̄ (non-res.)e+e− → e+e−W+W−
e+e− → e+νW−Z
e+e− → W+W−(ZZ)
e+e− → qq̄
Framework:
WHiZard 1.29 is the main event generator:- 6 fermions final states- all possible quark final states weregenerated- need to apply cuts to separate signalsfrom other processes- the anomalous α4 and α5 quarticcouplings are included- beam polarisation
Andres Osorio - Edinburgh, 14/10/2005 – p.7
< ↑ ↓ >
WW Scattering Analysis
We followed TESLA project specifications:(TeV Energy Super-conductingLinear Collider Accelerator)- C.M.E.:
√s = 800 GeV
- Polarised beams:0.80 e−, 0.40 e+ (PoWER Group)- Luminosity: L = 1000 fb−1
> L(1034 cm−2s−1)=5.8
Both ISR and FSR are turned On
Summary of the cross sections obtainedfrom our study:Type Generated pro ess: e
+e−
→ Cross Se t. [fb℄ Generator6 fermions W+W−νν̄ → qq̄qq̄νν̄ 9.21 WhizardZZνν̄ → qq̄qq̄νν̄ 4.05 Whizard
qq̄qq̄νν̄ (ba kgrounds) 6.55 WhizardWZeν → qq̄qq̄eν 38.50 Whizard
e+e−W+W−
→ e+e−qq̄qq̄ 234.80 Pythia*4 fermions W+W−
→ qq̄qq̄ 1948.10 Pythia*ZZ → qq̄qq̄ 142.90 Pythia*
e+e−tt̄ 1.30 Pythia*2 fermions tt̄ → X 136.90 Pythia *qq̄ 4464.60 Pythia** Pythia does not in lude a e+e− polarised beams option during integration
Andres Osorio - Edinburgh, 14/10/2005 – p.8
< ↑ ↓ >
WW Scattering Analysis
We followed TESLA project specifications:(TeV Energy Super-conductingLinear Collider Accelerator)- C.M.E.:
√s = 800 GeV
- Polarised beams:0.80 e−, 0.40 e+ (PoWER Group)- Luminosity: L = 1000 fb−1
> L(1034 cm−2s−1)=5.8
Both ISR and FSR are turned On
Summary of the cross sections obtainedfrom our study:Type Generated pro ess: e
+e−
→ Cross Se t. [fb℄ Generator6 fermions W+W−νν̄ → qq̄qq̄νν̄ 9.21 WhizardZZνν̄ → qq̄qq̄νν̄ 4.05 Whizard
qq̄qq̄νν̄ (ba kgrounds) 6.55 WhizardWZeν → qq̄qq̄eν 38.50 Whizard
e+e−W+W−
→ e+e−qq̄qq̄ 234.80 Pythia*4 fermions W+W−
→ qq̄qq̄ 1948.10 Pythia*ZZ → qq̄qq̄ 142.90 Pythia*
e+e−tt̄ 1.30 Pythia*2 fermions tt̄ → X 136.90 Pythia *qq̄ 4464.60 Pythia** Pythia does not in lude a e+e− polarised beams option during integration
We used the fast Detector SimulationSIMDET (v.4.01):- Tracking system: CCD vertex detector(1.5cm) + Forward Tracker- Magnetic field: 4 T
Calorimetry:- ECal resolution: ∆E/E = 0.2/
√E
- HCal resolution: ∆E/E = 0.5/√
E
3D cells - good granularity -> Energy Flowconcept.
Andres Osorio - Edinburgh, 14/10/2005 – p.8
< ↑ ↓ >
Z and W reconstruction
Main problem is to reconstruct Z and W pairs
Objects from the detector simulation areforced into 4 jets using the KT jet algorithm- exclusive mode, E recomb. scheme
If succeed, we then have 3 possiblecombinations
Use a 1C Kinematic Fit to find the best pairoptionQ(~x, ~λ) = (~x − ~x0)V −1(~x − ~x0) + 2~λ~f(~x)
Where: ~f(~x) : constraints~x : jet parameters (Ptot,θ,φ)~λ : Lagrange multipliers~V : error matrixError matrix: resolution functionsσP tot(pq), σθ(pq), σφ(pq, θq)
1c : Mjet1jet2 = Mjet3jet4
Andres Osorio - Edinburgh, 14/10/2005 – p.9
< ↑ ↓ >
Z and W reconstruction
Main problem is to reconstruct Z and W pairs
Objects from the detector simulation areforced into 4 jets using the KT jet algorithm- exclusive mode, E recomb. scheme
If succeed, we then have 3 possiblecombinations
Use a 1C Kinematic Fit to find the best pairoptionQ(~x, ~λ) = (~x − ~x0)V −1(~x − ~x0) + 2~λ~f(~x)
Where: ~f(~x) : constraints~x : jet parameters (Ptot,θ,φ)~λ : Lagrange multipliers~V : error matrixError matrix: resolution functionsσP tot(pq), σθ(pq), σφ(pq, θq)
1c : Mjet1jet2 = Mjet3jet4
Jet configurations
η
-5 -4 -3 -2 -1 0 1 2 3 4 5
φ
-4
-3
-2
-1
0
1
2
3
4
Jet Contents Jet oneJet twoJet threeJet fourReco. Jetsphotonspionsklong
Jet Contents
η
-5 -4 -3 -2 -1 0 1 2 3 4 5
φ
-4
-3
-2
-1
0
1
2
3
4
Jet Contents Jet oneJet twoJet threeJet fourReco. Jetsphotonspionsklong
Jet Contents
Andres Osorio - Edinburgh, 14/10/2005 – p.9
< ↑ ↓ >
Z and W reconstruction
Main problem is to reconstruct Z and W pairs
Objects from the detector simulation areforced into 4 jets using the KT jet algorithm- exclusive mode, E recomb. scheme
If succeed, we then have 3 possiblecombinations
Use a 1C Kinematic Fit to find the best pairoptionQ(~x, ~λ) = (~x − ~x0)V −1(~x − ~x0) + 2~λ~f(~x)
Where: ~f(~x) : constraints~x : jet parameters (Ptot,θ,φ)~λ : Lagrange multipliers~V : error matrixError matrix: resolution functionsσP tot(pq), σθ(pq), σφ(pq, θq)
1c : Mjet1jet2 = Mjet3jet4
Kinematic Fit results
p_Chi2
0 0.2 0.4 0.6 0.8 1
Eve
nts
0
200
400
600
800
1000
1200
p_Chi2
0 0.2 0.4 0.6 0.8 1
Eve
nts
0
500
1000
1500
2000
2500
Andres Osorio - Edinburgh, 14/10/2005 – p.9
< ↑ ↓ >
Z and W reconstruction
Recoil Mass distribution
(GeV)recoil
M0 100 200 300 400 500 600 700 800 900
Eve
nts
1
10
210
310
410
510
610
(signal)ννZZ
(signal)ννWW
(background)ννqqqq
6fermions (background)
4fermions (background)
2fermions (background)
Transverse momentum distribution
(GeV)TP
0 50 100 150 200 250 300 350 400
Eve
nts
1
10
210
310
410
510
610
710
(signal)ννZZ
(signal)ννWW
(background)ννqqqq
6fermions (background)
4fermions (background)
2fermions (background)
more...
General selection cuts- Recoil mass: Mrecoil ≥ 200 GeV- PT ≥ 20 GeV- Etrans ≥ 150 GeV- Scaled ycut parameter4.0 ≤ ln
p
ycut1,2 ∗ s ≤ 7.2
- Total missingmomentum| cos θPmiss
| < 0.99
- Most energetic track | cos θPEmax| < 0.99
- Charged tracks in each jet nTracks ≥ 2
- Probability (χ2) > 0.005- Ask for energy around highest track ≥ 2
GeV 5 deg cone
ZZ selection85 < M1C < 100 GeV
WW selection75 < M1C < 85 GeV
Andres Osorio - Edinburgh, 14/10/2005 – p.10
< ↑ ↓ >
Results
Cut flow summaryCut �ow Signals Ba kgrounds
νν̄WW νν̄ZZ qq̄qq̄ WZνe Othernone 9210 4050 6550 38500 6928600
Mrecoil 7128 3825 1935 49 32815
PT 6863 3664 1860 49 3450
ET 6347 3562 1688 42 2439
ycut 6141 3497 1601 42 1890
cos θPemax
6133 3493 1595 42 1886
cos θPmiss
6086 3470 1580 42 1778Charged tra ks 6086 3028 1490 21 1505
Econe 5971 2981 1468 9 1244
P (χ2) 5971 2295 1139 negl. 1047
νν̄ZZ selection
(GeV)ZM
50 60 70 80 90 100 110 120
Eve
nts
0
100
200
300
400
500
600
700
800
900
(signal)ννZZ
(signal)ννWW
(background)ννqqqq
6fermions (background)
4fermions (background)
2fermions (background)
Andres Osorio - Edinburgh, 14/10/2005 – p.11
< ↑ ↓ >
Results
Cut flow summaryCut �ow Signals Ba kgrounds
νν̄WW νν̄ZZ qq̄qq̄ WZνe Othernone 9210 4050 6550 38500 6928600
Mrecoil 7128 3825 1935 49 32815
PT 6863 3664 1860 49 3450
ET 6347 3562 1688 42 2439
ycut 6141 3497 1601 42 1890
cos θPemax
6133 3493 1595 42 1886
cos θPmiss
6086 3470 1580 42 1778Charged tra ks 6086 3028 1490 21 1505
Econe 5971 2981 1468 9 1244
P (χ2) 5971 2295 1139 negl. 1047
νν̄ZZ selection
(GeV)ZM
50 60 70 80 90 100 110 120
Eve
nts
0
100
200
300
400
500
600
700
800
900
(signal)ννZZ
(signal)ννWW
(background)ννqqqq
6fermions (background)
4fermions (background)
2fermions (background)
νν̄WW selection
(GeV)WM
50 60 70 80 90 100 110 120
Eve
nts
0
500
1000
1500
2000
2500
(signal)ννZZ
(signal)ννWW
(background)ννqqqq
6fermions (background)
4fermions (background)
2fermions (background)
Armentero-Podolanski plot
α-1 -0.5 0 0.5 1
0
10
20
30
40
50
60
70
80 (signal)ννZZ
(signal)ννWW
(background)ννqqqq
2fBackgs (background)
4fBackgs (background)
6fBackgs (background)
Andres Osorio - Edinburgh, 14/10/2005 – p.11
< ↑ ↓ >
Sensitivity study
Now I have Z and W candidates and a working analysis system.I combined the pairs of Z and W and make some distributions:
MWW and |cos θ∗| distribution for α4 = α5 = 0.0
m_WW [GeV]
0 100 200 300 400 500 600 700 800 900
Eve
nts
0
200
400
600
800
1000
1200
1400
1600
Signal+Backgrounds
Backgrounds
= 0.00004α= 0.00005α
-1L = 1000 fb
) .*θCos(
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1E
ven
ts0
50
100
150
200
250
300Signal+Backgrounds
Backgrounds
= 0.00004α= 0.00005α
-1L = 1000 fb
What happens when α4 and α5 are different from zero?
Expected rate change in the end results and therefore deviations from SM predictions
Andres Osorio - Edinburgh, 14/10/2005 – p.12
< ↑ ↓ >
Sensitivity study
I generated 20 scenarios, varying one of the a.c. at a time (10 for α5 = 0.0 and 10 forα4 = 0.0)
Andres Osorio - Edinburgh, 14/10/2005 – p.13
< ↑ ↓ >
Sensitivity study
I generated 20 scenarios, varying one of the a.c. at a time (10 for α5 = 0.0 and 10 forα4 = 0.0)
Looked at the cross section for each and compare it to SM
Andres Osorio - Edinburgh, 14/10/2005 – p.13
< ↑ ↓ >
Sensitivity study
I generated 20 scenarios, varying one of the a.c. at a time (10 for α5 = 0.0 and 10 forα4 = 0.0)
Looked at the cross section for each and compare it to SM
Coupling value
-0.25 -0.2 -0.15 -0.1 -0.05 -0 0.05 0.1 0.15 0.2 0.25
SM
σ/σ
-0.5
0
0.5
1
1.5
2
2.5
3
4α
5α
ννZZ
Coupling value
-0.25 -0.2 -0.15 -0.1 -0.05 -0 0.05 0.1 0.15 0.2 0.25
SM
σ/σ-0.5
0
0.5
1
1.5
2
2.5
3
4α
5α
ννWW
Andres Osorio - Edinburgh, 14/10/2005 – p.13
< ↑ ↓ >
Sensitivity study
I generated 20 scenarios, varying one of the a.c. at a time (10 for α5 = 0.0 and 10 forα4 = 0.0)
Looked at the cross section for each and compare it to SM
Coupling value
-0.25 -0.2 -0.15 -0.1 -0.05 -0 0.05 0.1 0.15 0.2 0.25
SM
σ/σ
-0.5
0
0.5
1
1.5
2
2.5
3
4α
5α
ννZZ
Coupling value
-0.25 -0.2 -0.15 -0.1 -0.05 -0 0.05 0.1 0.15 0.2 0.25
SM
σ/σ-0.5
0
0.5
1
1.5
2
2.5
3
4α
5α
ννWW
We expect better sensitivity to α5 than α4 in particular when looking at the νν̄WW channel
Andres Osorio - Edinburgh, 14/10/2005 – p.13
< ↑ ↓ >
Sensitivity study
Generated 12 extra scenarios with both α5 and α4 diff. from zero (each scenario had 400,000events, enough statistics)
Andres Osorio - Edinburgh, 14/10/2005 – p.14
< ↑ ↓ >
Sensitivity study
Generated 12 extra scenarios with both α5 and α4 diff. from zero (each scenario had 400,000events, enough statistics)
Rerun the whole analysis
Andres Osorio - Edinburgh, 14/10/2005 – p.14
< ↑ ↓ >
Sensitivity study
Generated 12 extra scenarios with both α5 and α4 diff. from zero (each scenario had 400,000events, enough statistics)
Rerun the whole analysis
Examples of the new MWW distributions:
Andres Osorio - Edinburgh, 14/10/2005 – p.14
< ↑ ↓ >
Sensitivity study
Generated 12 extra scenarios with both α5 and α4 diff. from zero (each scenario had 400,000events, enough statistics)
Rerun the whole analysis
Examples of the new MWW distributions:
m_WW [GeV]
0 100 200 300 400 500 600 700 800 900
Eve
nts
0
500
1000
1500
2000
2500
Signal+Backgrounds
Backgrounds
= -0.12674α= 0.00005α
-1L = 1000 fb
m_WW [GeV]
0 100 200 300 400 500 600 700 800 900
Eve
nts
0
500
1000
1500
2000
2500
Signal+Backgrounds
Backgrounds
= -0.09504α= 0.00005α
-1L = 1000 fb
m_WW [GeV]
0 100 200 300 400 500 600 700 800 900
Eve
nts
0
500
1000
1500
2000
2500
Signal+Backgrounds
Backgrounds
= -0.06334α= 0.00005α
-1L = 1000 fb
m_WW [GeV]
0 100 200 300 400 500 600 700 800 900
Eve
nts
0
500
1000
1500
2000
2500
Signal+Backgrounds
Backgrounds
= -0.03174α= 0.00005α
-1L = 1000 fb
Andres Osorio - Edinburgh, 14/10/2005 – p.14
< ↑ ↓ >
Sensitivity study
Generated 12 extra scenarios with both α5 and α4 diff. from zero (each scenario had 400,000events, enough statistics)
Rerun the whole analysis
Examples of the new MWW distributions:
m_WW [GeV]
0 100 200 300 400 500 600 700 800 900
Eve
nts
0
500
1000
1500
2000
2500
Signal+Backgrounds
Backgrounds
= -0.12674α= 0.00005α
-1L = 1000 fb
m_WW [GeV]
0 100 200 300 400 500 600 700 800 900
Eve
nts
0
500
1000
1500
2000
2500
Signal+Backgrounds
Backgrounds
= -0.09504α= 0.00005α
-1L = 1000 fb
m_WW [GeV]
0 100 200 300 400 500 600 700 800 900
Eve
nts
0
500
1000
1500
2000
2500
Signal+Backgrounds
Backgrounds
= -0.06334α= 0.00005α
-1L = 1000 fb
m_WW [GeV]
0 100 200 300 400 500 600 700 800 900
Eve
nts
0
500
1000
1500
2000
2500
Signal+Backgrounds
Backgrounds
= -0.03174α= 0.00005α
-1L = 1000 fb
In order to study the sensitivity I used a Binned Maximum Log Likelihood applied to bothMWW and |cos θ∗| distributions for each scenario
Andres Osorio - Edinburgh, 14/10/2005 – p.14
< ↑ ↓ >
Sensitivity study
Generated 12 extra scenarios with both α5 and α4 diff. from zero (each scenario had 400,000events, enough statistics)
Rerun the whole analysis
Examples of the new MWW distributions:
m_WW [GeV]
0 100 200 300 400 500 600 700 800 900
Eve
nts
0
500
1000
1500
2000
2500
Signal+Backgrounds
Backgrounds
= -0.12674α= 0.00005α
-1L = 1000 fb
m_WW [GeV]
0 100 200 300 400 500 600 700 800 900
Eve
nts
0
500
1000
1500
2000
2500
Signal+Backgrounds
Backgrounds
= -0.09504α= 0.00005α
-1L = 1000 fb
m_WW [GeV]
0 100 200 300 400 500 600 700 800 900
Eve
nts
0
500
1000
1500
2000
2500
Signal+Backgrounds
Backgrounds
= -0.06334α= 0.00005α
-1L = 1000 fb
m_WW [GeV]
0 100 200 300 400 500 600 700 800 900
Eve
nts
0
500
1000
1500
2000
2500
Signal+Backgrounds
Backgrounds
= -0.03174α= 0.00005α
-1L = 1000 fb
In order to study the sensitivity I used a Binned Maximum Log Likelihood applied to bothMWW and |cos θ∗| distributions for each scenario
BLLH takes as input: SM predicted signal, "observed" events, expected BKG and uncertaintiesin selection efficiencies, backgrounds and luminosity (not really needed ; = 0.001)
Andres Osorio - Edinburgh, 14/10/2005 – p.14
< ↑ ↓ >
Sensitivity study
I end up with 32 LLH values for every scenario and each distribution
Andres Osorio - Edinburgh, 14/10/2005 – p.15
< ↑ ↓ >
Sensitivity study
I end up with 32 LLH values for every scenario and each distribution
These are the results for those 20 scenarios mentioned before:
Andres Osorio - Edinburgh, 14/10/2005 – p.15
< ↑ ↓ >
Sensitivity study
I end up with 32 LLH values for every scenario and each distribution
These are the results for those 20 scenarios mentioned before:
4α
-0.15 -0.1 -0.05 0 0.05 0.1 0.15
-lo
g L
H
0
50
100
150
200
250
300
350
400
450
WWM combinedνν and WWννZZ
5α
-0.15 -0.1 -0.05 0 0.05 0.1 0.15
-lo
g L
H
0
50
100
150
200
250
300
350
400
450
WWM combinedνν and WWννZZ
4α
-0.15 -0.1 -0.05 0 0.05 0.1 0.15
-lo
g L
H
0
50
100
150
200
250
300
350
400
450
*}θCos{ combinedνν and WWννZZ
5α
-0.15 -0.1 -0.05 0 0.05 0.1 0.15
-lo
g L
H
0
50
100
150
200
250
300
350
400
450
*}θCos{ combinedνν and WWννZZ
Andres Osorio - Edinburgh, 14/10/2005 – p.15
< ↑ ↓ >
Sensitivity study
I end up with 32 LLH values for every scenario and each distribution
These are the results for those 20 scenarios mentioned before:
4α
-0.15 -0.1 -0.05 0 0.05 0.1 0.15
-lo
g L
H
0
50
100
150
200
250
300
350
400
450
WWM combinedνν and WWννZZ
5α
-0.15 -0.1 -0.05 0 0.05 0.1 0.15
-lo
g L
H
0
50
100
150
200
250
300
350
400
450
WWM combinedνν and WWννZZ
4α
-0.15 -0.1 -0.05 0 0.05 0.1 0.15
-lo
g L
H
0
50
100
150
200
250
300
350
400
450
*}θCos{ combinedνν and WWννZZ
5α
-0.15 -0.1 -0.05 0 0.05 0.1 0.15
-lo
g L
H
0
50
100
150
200
250
300
350
400
450
*}θCos{ combinedνν and WWννZZ
Observation: no symmetric behaviour of those LLH points with respect to the minimum (SMscenario)
Andres Osorio - Edinburgh, 14/10/2005 – p.15
< ↑ ↓ >
Sensitivity study
The combined results for those two distributions are
4α-0.15 -0.1 -0.05 0 0.05 0.1 0.15
5α
-0.15
-0.1
-0.05
0
0.05
0.1
0.15All distributions
combinedνν and WWννZZ
295.0 262.3 247.5 244.9 246.9244.9250.6 272.3 332.7 501.7
600.9
326.4
256.1
244.7
245.4
246.3
258.2
335.6
650.3
874.8256.5
368.6 246.4
258.2
263.7251.5
244.6
245.3
243.8 244.8
246.3
239.3
Andres Osorio - Edinburgh, 14/10/2005 – p.16
< ↑ ↓ >
Sensitivity study
Under construction!
The fit of those LLH values has been more complicated than expected
At the moment, I’m using S-plines to get a nice fit to those points andextract the limits that I want (and desperately need :) )
What are the estimated values?
Andres Osorio - Edinburgh, 14/10/2005 – p.17
< ↑ ↓ >
Conclusions
The hadronic decays of processes
e+e− → νν̄W+W−
e+e− → νν̄ZZ
can be exploited to find new physics provided LHC does not find a Higgs boson
If our ignorance about new physics is parametrised in term of the α4 and α5 anomalouscouplings, they could be measure at the ILC
I achieved to write an analysis framework to study hadronic and leptonic decays⊲ It is OO and it would be interesting to see what can do with semi-leptonic decays
I applied very useful analysis techniques (jet reconstruction, kinematic fit, binned loglikelihoods)
There is progress done on extracting the sensitivity to those anomalous couplings andtherefore provide 68/90 percent Confidence Levels
Andres Osorio - Edinburgh, 14/10/2005 – p.18
< ↑ ↓ >
Conclusions
If you can look into the seeds of time,And say which grain will grow and which will not
Speak to me.Macbeth, William Shakespeare
Andres Osorio - Edinburgh, 14/10/2005 – p.19
< ↑ ↓ >
Extra slide 1
Signal preparation using the following cuts in phase space:
147.0GeV ≤ m1qq̄ + m2
qq̄ ≤ 171.0 GeV : W
171.0 GeV ≤ m1qq̄ + m2
qq̄ ≤ 195.0 GeV : Z
|m1qq̄ + m2
qq̄ | ≤ 20.0 GeV
mνν̄ ≥ 100.0GeVMultipli ity: 3Resonan es: 3Log-enhan ed: 2t- hannel: 2 W+�eZ�eW�e+ (64) u (4)�d (32)�e (1)��e (2)� (8)s (16)e� (128)31
m_nunu
0 100 200 300 400 500 600 700
Eve
nts
0
5000
10000
15000
20000
25000
30000
35000
m_QuarkPairs_Sel
60 70 80 90 100 110 120
Eve
nts
60
70
80
90
100
110
120
Andres Osorio - Edinburgh, 14/10/2005 – p.20
< ↑ ↓ >
Extra slide 2
More distributions:
(GeV)TE
0 100 200 300 400 500 600 700 800 900
Eve
nts
1
10
210
310
410
510
610
(signal)ννZZ
(signal)ννWW
(background)ννqqqq
6fermions (background)
4fermions (background)
2fermions (background)
(GeV)cone
E0 20 40 60 80 100 120 140 160 180 200
Eve
nts
1
10
210
310
410
510
(signal)ννZZ
(signal)ννWW
(background)ννqqqq
6fermions (background)
4fermions (background)
2fermions (background)
)|Pmiss
θ|cos(0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Eve
nts
1
10
210
310
410
510
610
(signal)ννZZ
(signal)ννWW
(background)ννqqqq
6fermions (background)
4fermions (background)
2fermions (background)
)|Pemax
θ|cos(0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Eve
nts
1
10
210
310
410
510
610
(signal)ννZZ
(signal)ννWW
(background)ννqqqq
6fermions (background)
4fermions (background)
2fermions (background)
Andres Osorio - Edinburgh, 14/10/2005 – p.21
< ↑ ↓ >
Chierici et al results
Previous results:
Confidence Levels contours
-6
-4
-2
0
2
4
6
-6 -4 -2 0 2 4 6α4
α5
ZZνν and WWνν combined - Ref[Chierici et.al.]
Sensitivities (1 dimensional limits)1 DIM analysis 68% C.L. (TESLA 1000 fb−1 800 GeV and polarisation)α4 σ
−= −1.1 σ+ = 0.8
α5 σ−
= −0.4 σ+ = 0.3
My preliminary results⊲ using a polynomial fit
Sensitivities (2 dimensional limits)2 DIM analysis 68% C.L. (TESLA 1000 fb−1 800 GeV and polarisation)
α4 σ−
= −1.18 σ+ = 1.24
α5 σ−
= −0.95 σ+ = 0.96
Andres Osorio - Edinburgh, 14/10/2005 – p.22