Anomalous Right-handed Top Quark Couplings

Kang Young Lee(Konkuk Univ.)

Tevatron B physics workshop @ KISTI 2009. 8. 24.

Based on

J. P. Lee and KYL, arXiv:0809.0751. J. P. Lee and KYL, Phys. Rev. D 78, 056004 (2008).KYL and W. Y. Song, Phys. Rev. D 66, 057901 (2002).

Contents

• Introduction

• B→Xsγ decays

• Bq-Bq mixing

• Results• Top quark decays• Summary

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Introduction• LHC : the top quark factory in a sense

• More than 108-109 top quarks will be produced at LHC in a year (if LHC works at full power).

• Top quark couplings will be directly tested.

• Nondiagonal couplings may be observed.

• Anomalous top quark couplings are worth examining at present.

The CKM matrix

Not directly measured >0.74without unitarity D0 arXiv: 0803.0739CDF Note 8968

Effective Lagrangian

Vtqeff : measures SM-like left-handed couplings

ξq : measures right-handed couplings

Underlying new physics• Effective electroweak chiral Lagrangian• General Left-Right model (VL

CKM≠VRCKM)

• Etc.

New particles, neutral current interactions are ignored.

ΔB=1 effective Hamiltonian

Oi : SM operatorsOi‘ : chiral conjugate operators

SM Wilson coefficients

B→Xsγ decays

Turn on the right-handed couplings

with the new loop functions

Branching ratio

SM prediction at NNLOfor

M. Misiak and M. Steinhauser, NPB 764, 62 (2007)M. Misiak et al., PRL 98, 022002 (2007).

World average value of measurement HFAG

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Mass and width differences

Schreodinger equation

Note that

Bq-Bq mixing

Transition amplitude

with

SM predictions A. Lenz and U. Nierste, JHEP 06, 072 (2007)

Measurements

HFAG

CDF, PRL 97, 242003 (2006)D0, D0 note 5618-CONF

We obtain

ξb =0

Results

We obtain

ξs =0

No CP violation is predicted in Bs-Bs mixing in the SM. (No phase in Vts and Vtb)

Combined analysis of current data of Bs-Bs mixing tells us that there exists some CP violation.

Our prediction of the phase of M12s is dominated

by the phase of Vtqeff.

The phase of Bd-Bd mixing is directly measured.

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ξb =0

A. Lenz and U. Nierste, JHEP 06, 072 (2007)

ξs =0

sin 2β

Top quark decays

Nondiagonal top quark decays

which is insensitive to ξs and directly measure Vtseff .

Large deviation from the SM prediction is possible.

Note that in the SM

Can we measure it?

• Model independent study on the anomalous right-handed top quark couplings have been performed.

• Combined analysis of B→Xsγ decays and Bq-Bq mixing provides valuable information.

• Constraints on new physics parameters and predictions of departure from the SM are obtained.

• Nondiagonal top quark decays might examine the tsW coupling independently.

Summary

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