Experimental details

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Experimental details

• Select ? ? ??0? decays

• ? Ldt ? 13.3 fb?1 12.2 x 106 ?-pairs _at_ ?s ?
  ?(4S)

ee ? ? ?

• BKGs

??0?
a1?
Total contamination from other ? decays 10
ee ? qq
?
negligible
ee ? ee??
To lowest order ??? c?

• Use MC to determine c

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Introduction
Familiar story

• CPV observed in K-system (KS, KL)

• CPV sought/expected in B-system (B ? ?KS)

• CPV searches in ?, ? decays less popular

Novel CPV search technique in ? decays

• Overall technique is general

• Easily interpretable in MHDM

• Search done w/ CLEO detector

A1
A2ei?ei?
A

CPeven
CPodd
P ? A2 A12 A22 2A1A2cos?cos? -
2A1A2sin?sin?
CPodd
CPV sin? sin? ? 0
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? Distribution
SM Monte Carlo
fs 1
fs BWa0(980)
fs BWa0(1450)
??? x 10?3
? _at_ 90 CL
f
? x 10?2
? 0.8 ? 1.4
? 0.046 lt ? lt 0.022
fs 1
?1.2 ? 2.1
fs BWa0(980)
? 0.008 lt ? lt 0.006
? 0.6 ? 2.4
? 0.1 ? 0.4
? 0.019 lt ? lt 0.021
fs BWa0(1450)
0.1 ? 1.2
0.2 ? 1.2
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Search for Scalar Mediated ? Decays

• SM W-exchange

dN/d cos???0 a b cos2???0
? helicity angle

• non-SM w/ scalar exchanges

dN/d cos???0 a ( c1Re(?) c2Im(?) ) cos???0
b cos2???0

• ? direction unknown, switch to ?

? c2Im(?) cos ?
?
? 0.033 lt Im(?) lt 0.089 _at_ 90 CL
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