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Electroweak Symmetry Breaking and Triple Gauge
Coupling Measurements
Electroweak Symmetry Breaking and Triple Gauge
Coupling MeasurementsNCTS, Theory Division
Qi-Shu Yanwith S. Dutta, K. Hagiwara, K. Yoshida
NCTS, Theory DivisionQi-Shu Yan
with S. Dutta, K. Hagiwara, K. Yoshida
NTHU, 14:00-15:00, 22, March, 2007
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 2
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 3
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 4
Mass Origin and the Elctroweak Symmetry Breaking MechanismThree generationsToo many free parametersNo dark matter candidate…
Mass Origin and the Elctroweak Symmetry Breaking MechanismThree generationsToo many free parametersNo dark matter candidate…
The SM is an effective description of a fundamental theory!
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 5
EWSB and S ParameterEWSB and S Parameter
How conclusively precision data can rule out QCD-like
dynamics for EWSB sector?
How conclusively precision data can rule out QCD-like
dynamics for EWSB sector?
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 7
Triple Gauge CouplingsTriple Gauge CouplingsExamining the non-Abelian
structure of the SMMeasuring the size of weak
bosonsRemoving bkgd for new physics…
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 8
OutlineOutline
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 9
S in QCD-like Theories S in QCD-like Theories
S parameter is postive!
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 10
Precision of S in EvolutionPrecision of S in Evolution1990(2)
2004
1999
2006PDG
TT
SSˆ129
ˆ119
=
=
S parameter is negative!
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 11
Theoretical Effort for Solution Theoretical Effort for Solution
Produce a negative S in TCsInclude extra vector bosonsDecrease TExtra DimensionsADS/CFT…
Produce a negative S in TCsInclude extra vector bosonsDecrease TExtra DimensionsADS/CFT…
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 12
Shortages in Experimental Uncertainty Analysis
Shortages in Experimental Uncertainty Analysis
It is necessary to have an integrated and general analysis with two-, three-, and four-point functions data.
Model independent analysis is favored!
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 13
What’s New in this Talk?What’s New in this Talk?
S can be either positive or negative!!
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 14
2 Introduction to the EWCL2 Introduction to the EWCL
14 free parameters form the parameter space of the EWCL
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 15
OperatorsOperatorsTwo
PointFunction Four
Point function
ThreePointFunction
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 16
Bosonic VerticesBosonic Vertices
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 17
EWCL in Effective Field Theory
EWCL in Effective Field Theory
We expect that S parameter should be a running parameter!
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 18
Running Allowed by QFTRunning Allowed by QFT
We assume that perturbation method could be valid from Mz to UV Cutoff with only dimension 2 and 4 operators.
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 19
3 RGEs3 RGEs
Dimensional regularization,Background field method,Feynman-’t Hooft gauge,Modified MS,Heat kernel method
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 20
Check PointsCheck Points
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 21
4 Precision Data and Bounds4 Precision Data and Bounds
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 22
Precision Data of STUPrecision Data of STU
Inputs and formula to determine the two point chiral coefficients
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 23
Precision Data of STUPrecision Data of STU
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 24
Precision Data of TGCPrecision Data of TGC
Proof of Non-Abelian Structure of the SM
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 25
Precision Data of TGCPrecision Data of TGC
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 26
Bounds of QGCBounds of QGC
5 conditions (J=0 channel) to fix 5 free parameters
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 27
Chiral Coefficients in EWCLChiral Coefficients in EWCL
TGC errors are two order larger than those oftwo-point chiral coefficients
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 28
5 Uncertainty in S-T 5 Uncertainty in S-T TGCCase1
TGCCase
2
TGCCase3
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 29
Uncertainty in TUncertainty in T
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 30
SummarySummary
22.0)52.0(40.020.0)02.0(08.0
±++=±−−=
Λ
Λ
TS
When TGC & QGC uncertainty is taken into account
14.0)50.0(38.010.0)11.0(17.0
±++=±−−=
Λ
Λ
TS
When TGC & QGC uncertainty isn’t taken into account
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 31
6 Conclusions6 Conclusions
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 32
BackupBackup
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 34
DiscussionsDiscussions
Should S parameter run?
Subtracted dispersion relation without custodial symmetry
NTHU, Seminar, Q.S. Yan - Constraints on the EWCL from the precision data 35
Power counting problemPower counting problem
If the derivative power counting rule doesn’t hold, our results are the most conservative perturbation calculation.
• High order operators can affect STU and TGC fitting and QGC bounds significantly. Effective description might break down.• High order operators can affect the RGEs running dramatically, especially near the UV region.