Peter Krian

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CP violation and related issuesPart 6.5 b -gt
sss decays

• Peter Krian
• University of Ljubljana and J. Stefan Institute

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Contents
Why is b-gtsss so exciting? Measurements of CP
violation in b-gtsss
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b-gtsss decays
Vqs
W
f (h')
s
Pure penguin diagrams
b
q
s
Vqb
g
s
KS (KL)
d
VcbVcsAl2 VubVusAl4(r-ih)
First term dominates -gt l same as for J/yKS
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b-gtsss decays
However BR(B0 -gt h' K0) 5.8 10-5 considered
unexpectedly large Contribution from new
physics, i.e. in addition to the normal diagram
also exotic contributions (e.g. SUSY particles in
the loop)? Could show up as a modification to
the asymmetry parameters Sf and Af.
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CP asymmetry
Prediction to the leading order Sf-hfsin2f1
Af0
Sf
Af
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Result of 2003 (140/fb) surprise!

• Measurement points with error bars.
• Standard Model predictions dotted
• Result of the unbinned likelihood fit blue curve

Measure S-0.960.50, expect S sin2f10.731
0.056 not conclusive -gt need more
data
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Asymmetry in B-gtfKS and fKL
recently published
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Asymmetry in B -gt K K- KS and f0(980) KS
recently published
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Asymmetry in B-gthKS and wKS
recently published
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Vertex reconstruction in B -gt KS KS KS and p0
KS
No charged track from the B decay point
extrapolate the KS direction from the pp- vertex.
Check the method by measuring the asymmetry in
B-gtJ/yKS channel, use only KS for vertex
determination (instead of two leptons from J/y)
-gt OK!
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Asymmetry in B -gt KS KS KS and p0 KS
recently published
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Summary of asymmetry measurements
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Summary b-gtsqq
Measured average in b-gts penguin dominated modes
S0.390.11 World average sin2f10.726
0.037 2.9 s difference not conclusive -gt
still need more data -gt need more accurate
theoretical predictions mode by mode
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Backup slides
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B ? hKs h not a pure ss state -gt appart
from P(VcbVcsAl2) and P(VubVusAl4(r-ih)) also
color and Cabbibo suppressed b ? u
T(VubVusAl4(r-ih))