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.