?(5S) Physics at Belle

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?(5S) Physics at Belle
06/03 lcpac
status of efforts beam energy and 5S status
of proposal to LCPAC
K. Kinoshita
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?(5S) physics 

• Motivation study Bs
• Low CP-asymmetry in SM
• -gt sensitivity to New Physics
• ????CP/?O(10) in SM
• -gt differences in CP, flavor eigenstates
• compare to B decay
• -gt quark-hadron duality,
• fine-tune hadronic models

Why study Bs at ?(5S)? exclusive B pair events
(quantum coherence), high trigger eff, clean
?s previous best 0.42 fb1 (CLEO) 2003
June 2005 3-day engineering run, 1.86 fb1 to
study ?(5S) properties, Bs prospects
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Results from ?(5S) engineering run 
KEKB operation peak scan (5 pts, 30 pb1 ea)
30 pb1 pts, -gt 10869 MeV (consistent w CESR)
_at_peak smooth operation, Lmax 1.39 x 1034
cm2s-1
?(5S) properties event fractions Bs()Bs(),
Bq()Bq(), BqBq()p, BqBqpp fsBs fraction
from B(5S-gtDsX)weighted B-gtDsX,
Bs-gtDsX fs(16.41.44.1), or 4.7 x 104 x 2
Bs/fb-1 (competitive) BsBs fraction
Bs() masses M(Bs) 54181 5 MeV M(Bs)
537013 MeV
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Results from ?(5S) engineering run 
Bs properties/prospects (see A. Schwartz talk for
full list)
Search for Rare Decays
Theory 0.2 0.4 0.01 100 200 200
b-gts penguin/b-gtu spectator b-gts
penguin intrinsic penguin spectator
Best
?? sensitivity to new physics Ds()Ds()-
Aleksan, Dunietz, Kayser Z. Phys., C54, 653
(1992) ??s/?s 2xB(Ds()Ds()-) theory
??s/?s O(0.10)