Peter Krian

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CP violation and related issuesPart 8 angle
f3(g)

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

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Contents
How to measure f3? f3 from interference of a
direct and colour suppressed decay
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How to measure f3?

• No easy (tree dominated) channel to measure f3
  through CP violation.
• Any other idea? Yes.

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f3 from interference of a direct and colour
suppressed decay
f any final state, common to decays of both D0
and D0
(rih) eif3
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f3 from interference of a direct and colour
suppressed decay
Gronau,London,Wyler, 1991 B- ?
K-D0CP Atwood,Dunietz,Soni, 2001 B- ?
K-D0()Kp- BelleGiri,Zupan et al., 2003 B- ?
K-D0()Kspp-
Dalitz plot
Density of the Dalitz plot depends on f3 Matrix
element
or any other common 3-body decay
Sensitivity depends on
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What is a Dalitz plot?
Example three body decay X-gtabc. Mij denotes
the invariant mass of the two-particle system
(ij) in a three body decay. Kinematic boundaries
have been drawn for equal masses ma mb mc
0.14 GeV and for two values of total energy E of
the three-pion system. Resonance bands drawn for
states (ab) and (bc) corresponding to a
(fictitious) resonance with M0.5 GeV and G0.2
GeV dot-dash lines show the locations a (ca)
resonance band would have for this mass of 0.5
GeV, for the two values of the total energy E.
The pattern becomes much more complicated, if the
resonances interfere.
Richard H. Dalitz, "Dalitz plot", in
AccessScience_at_McGraw-Hill, http//www.accessscienc
e.com.
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f3 from interference of a direct and colour
suppressed decay
Reconstruct B- ? D0 K- decays.
B? D0 K D0 ? Kspp
DE Mbc
B? D0 p miss-id
Use continuum D0 from D? D0p, D0 ? Kspp
decay to model Dalitz plot density.
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f3 from interference of a direct and colour
suppressed decay
Use D0 decays from D? D0p, D0 ? Kspp decay
to model Dalitz plot density in
two variables m2(Ksp)m2 and m2(Ksp-)m-2
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f3 from interference of a direct and colour
suppressed decay
B? D0K
B-? D0K-
m2(Ksp-)
m2(Ksp-)
m2(Ksp)
m2(Ksp)
Visible asymmetry
f3 (68 1415 13 11)o
Fit with f3,d,rB free
22o lt f3 lt 113o _at_ 95 C.L.
rB 0.21 0.08 0.03 0.04
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f3 vs. rB plots
rB
90
68
f3