A like-sign dimuon charge asymmetry induced by the anomalous top quark couplings
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A like-sign dimuon charge asymmetry
induced by the anomalous top quark
couplings
이 강 영
( 건국대학교 )
@ 연세대학교 , 서울 2010. 11. 30.
Based on
J. P. Lee and KYL, arXiv:1010.6132.
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
• D0 like-sign dimuon charge asymmetry
• Constraints
• Results
• Top quark decays
• Summary
Introduction
• Like-sign dimuon charge asymmetry measured by D0 at Tevatron shows 3.2 σ deviation from the SM prediction.
• More than 108-109 top quarks will be produced at LHC in a year (at full power run).
• Top quark couplings will be directly tested and nondiagonal couplings may be observed at LHC.
• Anomalous top quark couplings are worth examining at present.
The CKM matrix 2008 Nobel prize awarded
Not directly measured
>0.74 without unitarity
D0 PRD78, 012005 (2008)CDF 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 (VLCKM≠VR
CKM)
• Etc.
New particles, neutral current interactions are ignored.
D0 like-sign dimuon charge
asymmetry production at Tevatron
One muon comes from direct semileptonic decay :
The other muon comes from semileptonic decay after neutral B meson mixing :
Xb
XBB 00
bb
The dimuon charge asymmetry of semileptonic B decays is defined by
bb NN , : Number of events of two b hadrons decaying into
two muons with the charge of the same sign
comes from the asymmetry of the “wrong sign” semileptonic decays,
bslA
which are due to the oscillations of neutral Bd and Bs mesons.
Since both Bd and Bs mesons are produced at the Tevatron,
is a linear combination of and .
Y. Grossman, Y. Nir, G. Raz, PRL 97, 151801 (2006)
The Standard Model Predictions
A. Lenz, U. Nierste, JHEP 0706, 072 (2007)
Non-zero Difference between Bq and Bq decays
Mixing induced CP violation
-
D. Tsybychev, Talk given at the Johns Hopkins Workshop
measurements
The measured value shows deviations from the standard model prediction.
Previous measurement
arXiv:1005.2757 [hep-ex]
ΔB=1 effective Hamiltonian
Oi : SM operatorsOi‘ : chiral conjugate operators
SM Wilson coefficients
Constraint I : B→Xsγ decays
Turn on the right-handed couplings
with the new loop functions
Branching ratio
SM prediction at NNLO
for
M. Misiak and M. Steinhauser, NPB 764, 62 (2007)M. Misiak et al., PRL 98, 022002 (2007).
World average value of measurement HFAG
A.L. Kagan, M. Neubert, EPJ, C7, 5 (1999)
-
Mass and width differences
Schreodinger equation
Note that
Constraint II : 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
B→Xsγ B→Xsγ + Bs mixing
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 Vtseff.
The phase of Bd-Bd mixing is directly measured.
-
-
-
ξb =0
A. Lenz and U. Nierste, JHEP 06, 072 (2007)
ξs =0
sin 2βBs mixing Bd mixing
Including dimuon charge asymmetry data
B→Xsγ B→Xsγ + Bs mixingB→Xsγ + Bs mixing + Asl
b
ξb =0
ξb =0
B→Xsγ B→Xsγ + Bs mixingB→Xsγ + Bs mixing + Bd mixing B→Xsγ + Bs mixing + Bd mixing + Asl
b
ξs =0
ξs =0
Wts
Wtb
Top quark decays
Nondiagonal top quark decays
which is insensitive to ξs and directly measure Vtseff .
Large deviation from the SM prediction is possible.
in the SM, but shifted in our approach,
Note that in the SM
Can we measure it?
Including dimuon data
• Impact of the anomalous right-handed top quark couplings on the like-sign dimuon charge asymmetry at Tevatron is studied in a model independent way.
• Under the constraints from B→Xsγ decays and Bq-Bq mixing, the dimuon asymmetry can be explained.
• Constraints on new physics parameters and predictions of departure from the SM are obtained.
• Nondiagonal top quark decays might examine the tsW coupling directly and independently.
Summary
-
Backup Slides
Including dimuon charge asymmetry data
B→Xsγ B→Xsγ + Bs mixingB→Xsγ + Bs mixing + Asl
b
ξb =0
Preliminary
ξb =0
Preliminary
top related