1. 06/03 lcpac K. Kinoshita status of efforts beam energy and 5S status of proposal to LCPAC  (5S) Physics at Belle

2. LCPAC March 2006 K. Kinoshita 2  (5S) physics CLEO PRL 54, 381 (1985)  (5S) -> B s (*) B s (*) B q (*) B q B q (*) π B q B q ππ Motivation: study B s Low CP-asymmetry in SM -> sensitivity to New Physics  CP /  =O(10%) in SM -> differences in CP, flavor eigenstates compare to B decay -> quark-hadron duality, fine-tune hadronic models Why study B s at  (5S)? exclusive B pair events (quantum coherence), high trigger eff, clean  ’ s previous best: 0.42 fb – 1 (CLEO) 2003 June 2005: 3-day engineering run, 1.86 fb – 1 to study  (5S) properties, B s prospects

3. LCPAC March 2006 K. Kinoshita 3 Ds+π–Ds+π– D s *+ π – D s (*)+  – Bs*Bs*Bs*Bs* BsBsBsBs BsBs*BsBs* Results from  (5S) engineering run KEKB operation: peak scan (5 pts, 30 pb – 1 ea) 30 pb – 1 pts, -> 10869 MeV (consistent w CESR) @peak: smooth operation, L max ~ 1.39 x 10 34 cm – 2 s -1  (5S) properties event fractions: B s (*) B s (*), B q (*) B q (*), B q B q (*) π, B q B q ππ f s =B s fraction: from B(5S->D s X)={weighted B->D s X, B s ->D s X} f s =(16.4±1.4±4.1)%, or ~ 4.7 x 10 4 x 2 B s /fb -1 (competitive) B s * B s * fraction B s (*) masses M(B s *) = 5418±1 ± 5 MeV M(B s ) = 5370±1±3 MeV

4. LCPAC March 2006 K. Kinoshita 4 Results from  (5S) engineering run B s properties/prospects (see A. Schwartz talk for full list) Search for Rare Decays b->s penguin/b->u spectator b->s penguin intrinsic penguin spectator Best Theory 0.2 0.4 0.01 100 200  : sensitivity to new physics D s (*)+ D s (*)- : Aleksan, Dunietz, Kayser Z. Phys., C54, 653 (1992)   /   ~ 2xB(D s (*)+ D s (*)- ) theory:   /   =O(0.10)