CPV Search in 0 Decays

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CPV Search in ? ? ??0?? Decays
Thomas Coan Southern Methodist University
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?
?
?
?
fv
fs

A
W
H
?
?
?0
?0
Maximize CPV sensitivity Use specific model ? 3
Higgs Doublet Model
( S. Weinberg, PRL 37 (1976) 657 )
CPeven
ASM ? Jlepfvei?v(p? - p?0)
fv BW?(770)
w/
CPodd
CPeven
AH ? Jlep? ei?fs ei?s M??0
w/ fs model dependent
fs 1
BWa0(980)
BWa0(1450)
? ? ??0? final state

• BR( ? ? ??0? ) ? 25

• High selection efficiency

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Optimal CP Sensitive Variable
P ? A2
P Peven Podd
Ps are computed from fv, fs, ? and kinematic
quantities
What CP-odd observable ? to use?

• Choice of ? not unique

• Select ? for smallest statistical error

CP sensitive variable
Atwood Soni, PRD, 45 (1992) 2405
Gunion Grzadkowski, PRD, 77 (1992) 5172
? is complicated function. No immediate intuitive
appeal.
?
?
c1? c3? c5? ...
? ? ? ? 0 ? CPV
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Monte Carlo ? Distribution SM and 3HDM
No CPV ( ? 0 )
Maximal CPV ( ? 1 )
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Systematic Error Checks

• Oall detector response asymmetry checked w/ ? ?
  q q ? decays

• Track reconstruction efficiency v. ? q

p(??)/p(??) v. p

• p(?), p(?0) reconstruction errors ? ?

• ? asymmetry from BKG ?

Negligible effects on ???
p GeV/c
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Summary
Search for CPV in 3HDM w/ fs 1
? 0.046 lt Im(?) lt 0.022 _at_ 90 CL
(preliminary)

• ??? - technique, 1st of its type

• Improves previous CLEO result ( PRL 81 (1998)
  3823 ) by factor of ? 4

Pseudo-helicity angle distribution analysis
w/ single ? ? ??0? decays
? 0.033 lt Im(?) lt 0.089 _at_ 90 CL
(preliminary)