New Physics Search through → t t → l X / b X Kazumasa OHKUMA (Fukui Tech.) 7/Oct./2005@Shonan...

New Physics Search through → t t → l X / b X

New Physics Search through → t t → l X / b X

Kazumasa OHKUMA (Fukui Tech.)

7/Oct./2005@Shonan Village

hep-ph/0508183

7th International Symposium on Radiative Corrections

PLB593 (2004) 189 & NPB689 (2004) 108

Based on

Z. Hioki （ Tokushima　 Univ.）B.Grzadkowski (Warsaw Univ.) ,

J.Wudka （ UC Riverside)

In collaboration with

I. Introduction

II. Framework

III. Optimal-Observable Analysis

IV. Summary

Plan of talk

I. Introduction★★StandardStandard 　　 Model Model isis 　　 composed bycomposed by

Electro-weak theory and Quantum chromodynamics

Highly Successful Model

There are some unsolved problemsBut!!

•Many parameters (Couplings, CKM, ‥‥)•Origin of masses•Hierarchy

New Physics beyond Standard ModelNew Physics beyond Standard Model

Page-17/Oct./2005 Shonan Village7th International Symposium on Radiative Corrections

How to search for the signal of new physics?How to search for the signal of new physics?

One of answers:Top quark physics.

Why?

Ans. (1) Heaviest particle observed to date ! !

There are some 　 advantageous properties;

(i) Sensitive to SSB

(ii) Decay as a free quark !

Clear information about top Clear information about top quarkquarkClear information about top Clear information about top quarkquark

τ<<10-23[s]

(2) On top quark sector, C P is negligible in SM ! ! Large CP indicates new physics Large CP indicates new physics

contribution. contribution. Large CP indicates new physics Large CP indicates new physics contribution. contribution.

HiggsHiggs


Interesting option of ILC. Initial CP parity is controllable !!

Only CP-even state at ee collider

We estimateWe estimate

In order to study non-standard effect In order to study non-standard effect

, we focus on

• Couple to CP-odd scalar particles

Statistical Significance of non-Standard Couplings

Photon ColliderPhoton Colliderat

and probeand probeOptimal Beam Polarizations for New Physics Search


SM Lagrangian is modified by 　　 quantum effect 　 of new physics.

Effective Lagrangian approachEffective Lagrangian approach★

W.Buchmuller and D.Wyler, NPB268(1986)621

Model Independent Analysis

Model 　 Dependent 　Analysis

Complementary relation

•　 New fields are not in existence under scale.•　 New heavy particles are decoupled.

Assumption

: SU(3) X SU(2) X U(1) invariant Dim.6 operators: Energy scale of new physics

: non-standard couplings

II. 　 Framework

dk


Effective Operators for γγ→ t t ｔｔ　interaction (Top EDM)

Top Quark Production Top Quark Production

ｔｔ　interaction (Contact Interaction)

We found relations between EDM operators and

Contact interaction operators.Page-57/Oct./2005 Shonan Village7th International Symposium on Radiative Corrections

Relations of OperatorsBianchi identities and SM classical

motion of equations for quark and vector bosons lead us to


Need not to consider Contact Interaction.

× ×

× × ×

× × ××

×

× : No contribution

Effective Operators for →(H)→t t

H interaction (Higgs property)

Effective Operators for t → 　ｂ W ｔｂ W interaction

Top Decay Top Decay


Feynman rules for on-shell photos

(1) C P-conserving tt vertex

(2) C P-violating tt vertex

(1) C P-conserving H vertex

(2) C P-violating H vertex

★ Top Electric Dipole Moment 　 interaction :

★ Higgs 　 Exchange interaction : h


★ Decay Vertex


Feynman Diagrams for → 　ｔｔFeynman Diagrams for → 　ｔｔS.Y.Choi and Hagiwara

P.Poulos and S.D.Rindani

PLB359(1995)369,

PRD56(1997)6835,

etc.

In actual experiment, their mixed signals will be observed !!In actual experiment, their mixed signals will be observed !!

B.Grzadkowski and J.F.Gunion, PLB294(1992)316,G.J.Gounaris and G.P.Tsirigoti,PRD56(1997)3030,E.Asakawa, J.Kamoshita, A.Sugamoto and I.Watanabe,EPJC14(2000)335,E.Asakawa, S.Y.Choi,K.Hagiwara and J.S.Lee, PRD62(2000)115005,R.M.Godbole, S.D.Rindani and R.K.Shigh PRD67(2003)095009, etc.

All possible non-standard interactions are taken into account.

All possible non-standard interactions are taken into account.


III. Optimal 　 Observable Analysis

Method for estimating the precision of determination of relevant non-standard couplings.

What is Optimal Observable Analysis ?

How to estimate these precision ? J. F. Gunion, et.al, PRL77 (1996) 5172

Suppose following distribution:

: final-state phase space

: known functions ← Calculable

: model-independent coefficients

Cross section


Extract C i using appropriate weighting function

Extract

In general, different choice for the are possible.

There is a unique choice which minimizesthe resultant statistical uncertainty: Ci.

Such function is given by


Inverse matrix of Mij :

Statistical uncertainty of Ci is given by

Calculable

: Total cross section

: Event number

Apply to analysis of final-lepton’s energy and angular distribution for . Page-137/Oct./2005 Shonan Village7th International Symposium on Radiative Corrections

Application

Final-lepton’s energy and angular distribution

EDM

Higgs

Decay

Calculable

e.g.


Matrix Element Mij

where I,J=1, ,6‥ correspond to SM, １ , ２ , h1, h2 and d, respectively.

Inverse

EX.


Parameters of Photon collider

: Degree of circular polarization of initial laser

: Initial electron longitudinal polarization

: Degree of linear polarization of initial laser with azimuthal angle

High energy colliding beams of polarized photons are generated by Compton backscattering


Probing optimal photon beam polarizationsEstimate the uncertainty of

couplings

Search for the combinations that make minimal, varying polarization parameters as

Note


Unfortunately !Our results for Xij are very unstable

even a tiny fluctuation of Mij changes Xij significantly !

All the couplings cannot be determined at the same time from only . Refrain from determining all the couplings

at once.

Assumption

Some non-standard couplings Ci have been measured in other processes e.g.


Result

5 and 4 parameters analyses lead to unstable solutions.

3 and 2 parameters analysis give stable solutions within 10% ambiguity

Under the conditions: , ,

Some results are presented hereafter.

3 parameter case : 3 combinations are OK final lepton 1 final bottom 2

2 parameter case : 68 combinations are OK final lepton 39 final bottom 29


: detection efficiency

Results (3 parameter analysis)

Charged-lepton detectionBottom-quark detection

withwith

(2 of 3)

Not so small !


Results (2 parameter analysis)There are 68 stable solutions.

HoweverAll the stable solutions do not give us good statistical precisions.

Two statistical uncertainties ( , ) satisfy

is minimal

for each pair of and



mH=300 GeV•Final lepton detection



mH=300 GeV•Final bottom quark detection



Independent of Higgs mass•Final lepton detection

Note

There are no combinations which make 2 small (2 < 0.1).


Probe Optimal beam polarizations for New physics search

To study non-standard Effect in top quark production,

IV. Summary

we focus on .

Statistical uncertainties were estimated- CP conserving and violating tt coupling :1,2

- CP conserving and violating H coupling :h1,h2

- anomalous tbW coupling :d

using Optimal Observable method.

Model independent analysis were performed using effective low-energy Lagrangian.


Adjusting beam polarization gives us good statistical precisions: in two parameter analysis

- all non-standard couplings （ except for 2 ）　 could be determined with accuracy better than 0.1 with a integrated luminosity of 500 fb-1.

- the statistical uncertainty of 2 is still large in this analysis.

We look for anther processes to determine 2.

It is useful to probe the proprieties of Higgs boson couplings.


Back up

Comparing ee and colliders Top quark productions

collideree collider

It is possible to measure tt coupling at both colliders.Within the framework of the effective Lagrangian, we can estimate .

Appendix7/Oct./2005 Shonan Village7th International Symposium on Radiative Corrections

In the e e t t l / b X , 2 could not be measured.

Note!

In t t l / b X , 2 could be measuredthough it’s not to be measured precisely.

B.Grazkowski and Z. Hioki, NP B484 (1997) 17, NP B585 (2000) 3L. Brzezinski, Grzadkowski and Z. Hioki, Int. J. Mod. Phys. A14 (1999) 1261


1 parameter Optimal Observable analysis

t t l X

e e t t l X

ee colliders will give us slightly good precision.

Comparison of 1 measurement in e e and colliders


Comparing e e and colliders

ee collider ( e e t t l / b X ) It seems to be slightly favored to measure 1. 2 could not measure in the process.

collider ( t t l / b X )

2 could be measured in the process. (precision is not good) It seems to be very useful for testing the Higgs coupling. Looking for the processes or observable that

make statistical sensitivity small for the measuring 2 is important !

Circular polarization AsymmetryCircular polarization Asymmetry

(-) (-)


Linear polarization AsymmetryLinear polarization Asymmetry



mH=300 GeV•Final bottom quark detection


New Physics Search through → t t → l X / b X Kazumasa OHKUMA (Fukui Tech.) 7/Oct./2005@Shonan...

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