New Physics Search through gg ? t t ? l X / b X

1
New Physics Search through gg ? t t ? l X / b X

7th International Symposium on Radiative
Corrections
7/Oct./2005_at_Shonan Village
Kazumasa OHKUMA (Fukui Tech.)
Based on
hep-ph/0508183
PLB593 (2004) 189 NPB689 (2004) 108
In collaboration with
Z. Hioki (Tokushima Univ.)
B.Grzadkowski (Warsaw Univ.) ,
J.Wudka (UC Riverside)
2
Plan of talk

• I. Introduction
• II. Framework
• III. Optimal-Observable Analysis
• IV. Summary

3
I. Introduction

?Standard Model is composed by
Electro-weak theory and Quantum chromodynamics
Highly Successful Model
But!!
There are some unsolved problems

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

New Physics beyond Standard Model
4
How to search for the signal of new physics?
Top quark physics.
One of answers
Why?
Ans.
There are some advantageous properties
(1) Heaviest particle observed to date ! !
(i) Sensitive to SSB
Higgs
(ii) Decay as a free quark !
tltlt10-23s
Clear information about top quark
(2) On top quark sector, C P is negligible in SM
! !
Large CP indicates new physics contribution.
5
In order to study non-standard effect
, we focus on

Photon Collider
at

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

• Couple to CP-odd scalar particles

We estimate
Statistical Significance of non-Standard Couplings
and probe
Optimal Beam Polarizations for New Physics Search
6
II. Framework
Complementary relation
Model Dependent Analysis
Assumption

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

• SM Lagrangian is modified by
• quantum effect of new physics.

SU(3) X SU(2) X U(1) invariant Dim.6 operators
non-standard couplings
W.Buchmuller and D.Wyler, NPB268(1986)621
7

• Top Quark Production

Effective Operators for ??? t t

• ttg interaction (Top EDM)

• ttgg interaction (Contact Interaction)

We found relations between EDM operators and
Contact interaction operators.
8
Relations of Operators
Bianchi identities and SM classical motion of
equations for quark and vector bosons lead us to
9
(No Transcript)
10
Effective Operators for gg?(H)?t t

• ggH interaction (Higgs property)

• Top Decay

Effective Operators for t ? b W

• tbW interaction

11
Feynman rules for on-shell photos
? Top Electric Dipole Moment interaction ag
(1) C P-conserving ttg vertex
(2) C P-violating ttg vertex
? Higgs Exchange interaction ah
(1) C P-conserving ggH vertex
(2) C P-violating ggH vertex
12
? Decay Vertex
13
Feynman Diagrams for gg ? t t
S.Y.Choi and Hagiwara
PLB359(1995)369,
P.Poulos and S.D.Rindani
PRD56(1997)6835,
etc.
B.Grzadkowski and J.F.Gunion, PLB294(1992)316, G.J
.Gounaris and G.P.Tsirigoti,PRD56(1997)3030, E.Asa
kawa, 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.
In actual experiment, their mixed signals will be
observed !!
All possible non-standard interactions are taken
into account.
14
III. Optimal Observable Analysis
What is Optimal Observable Analysis ?
Method for estimating the precision of
determination of relevant non-standard
couplings.
J. F. Gunion, et.al, PRL77 (1996) 5172
Suppose following distribution
Cross section
final-state phase space
known functions ? Calculable
model-independent coefficients
15
Extract C i using appropriate weighting
function
Extract
In general, different choice for the are
possible.
There is a unique choice which minimizes the
resultant statistical uncertainty DCi.
Such function is given by
16
Inverse matrix of Mij
Calculable
Statistical uncertainty of Ci is given by
Event number
Total cross section
Apply to analysis of final-leptons energy and
angular distribution for .
17
Application
e.g.
Final-leptons energy and angular distribution
EDM
Higgs
Decay
18
Matrix Element Mij
Inverse
where I,J1,?,6 correspond to
SM, g1,g2, h1, h2 and d, respectively.
EX.
19
Parameters of Photon collider
High energy colliding beams of polarized photons
are generated by Compton backscattering
Initial electron longitudinal polarization
20
Probing optimal photon beam polarizations
Estimate the uncertainty of
couplings
21
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.
22
Result
Under the conditions , ,
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
Some results are presented hereafter.
23
Results (3 parameter analysis)
(2 of 3)
Bottom-quark detection
Charged-lepton detection
with
with
detection efficiency
24
Results (2 parameter analysis)
There are 68 stable solutions.
However
All the stable solutions do not give us good
statistical precisions.
Two statistical uncertainties ( , )
satisfy
is minimal
25
Results (2 parameter analysis)

• mH300 GeV

• Final lepton detection

26
Results (2 parameter analysis)

• mH300 GeV

• Final bottom quark detection

27
Results (2 parameter analysis)

• Independent of Higgs mass

• Final lepton detection

28
IV. Summary
To study non-standard Effect in top quark
production,
we focus on .

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

• Statistical uncertainties were estimated
• CP conserving and violating ttg coupling
  ag1,ag2
• CP conserving and violating ggH coupling
  ah1,ah2
• anomalous tbW coupling ad
• using Optimal Observable method.

Probe Optimal beam polarizations for New
physics search
29

• Adjusting beam polarization gives us
• good statistical precisions
• in two parameter analysis
• all non-standard couplings (except for ag2)
• could be determined with accuracy better
• than 0.1 with a integrated luminosity of
• 500 fb-1.
• the statistical uncertainty of ag2 is still
• large in this analysis.

It is useful to probe the proprieties of Higgs
boson couplings.
We look for anther processes to determine ag2.
30
Back up
31
Comparing ee and gg colliders

• Top quark productions

gg collider
32
In g g t t l / b X , ag2 could be
measured though its not to be measured
precisely.
B.Grazkowski and Z. Hioki, NP B484 (1997)
17, NP B585 (2000) 3 L. Brzezinski, Grzadkowski
and Z. Hioki, Int. J. Mod. Phys. A14 (1999)
1261
33
1 parameter Optimal Observable analysis
34

• Comparing e e and g g colliders

• ee collider ( e e t t l / b X )

• It seems to be slightly favored to
• measure ag1.
• ag2 could not measure in the process.

• gg collider ( gg t t l / b X )

• ag2 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 ag2 is important !
35
Circular polarization Asymmetry
36
Linear polarization Asymmetry
37
Results (2 parameter analysis)

• mH300 GeV

• Final bottom quark detection