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Heavy Quark Production and Decay in the Upsilon region: Results from Belle

5th International Conference on Quark Confinement, Gargnano, Italy, September 10-14, 2002. Heavy Quark Production and Decay in the Upsilon region: Results from Belle. Hadronic physics in the Upsilon region •Belle and KEKB Selected Results: Prompt J/ y and double charm production

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Heavy Quark Production and Decay in the Upsilon region: Results from Belle

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  1. 5th International Conference on Quark Confinement, Gargnano, Italy, September 10-14, 2002 Heavy Quark Production and Decay in the Upsilon region: Results from Belle • Hadronic physics in the Upsilon region • •Belle and KEKB • Selected Results: • Prompt J/y and double charm production • Observation of hc’ • Production of charmonia in B decay • Rate of h’ from B decay • •Summary Kay Kinoshita University of Cincinnati Belle Collaboration

  2. Heavy quarks in the  region b c } B { } meson HADRONIZATION } meson in cms, EB=Ee, ~1 nb in cms, Ec=Ee, ~1 nb most c-hadrons have p>(kinematic limit for b->c) Well-defined (& measureable!) production rate, energy BB threshold At Belle, ∫L(4S)dt/∫L(<4S)dt~0.10

  3. Beams: KEKB bg = 0.425 s(E*beam) = 2.6 MeV IP size = 77µm(x) x 2.0µm(y) x 4.0mm(z) Lmax = 7.4 X 1033 cm–2s–1 (design: 1x1034) Data (6/1999–7/2002) Ldt = 89.6 fb–1@(4S), 9.0 fb–1off (~9x107 B, c events) e– 8.0 GeV 22 mr e+ 3.5 GeV

  4. Belle detector Charged tracking/vertexing - SVD: 3-layer DSSD Si µstrip – CDC: 50 layers (He-ethane) Hadron identification – CDC: dE/dx – TOF: time-of-flight – ACC: Threshold Cerenkov (aerogel) Electron/photon – ECL: CsI calorimeter Muon/KL – KLM: Resistive plate counter/iron

  5. Belle Collaboration 274 authors, 45 institutions many nations

  6. Prompt J/y production (PRL88, 052001 (2002)) 29.4 fb-1(4S)+3.0 fb-1(<4S) Test of NRQCD (explains y(2S) excess @ FNAL): e+e- -> J/y gg (dominant) + J/y g + J/y cc (~10%) Predict s~0.8-1.7 pb, peak @ pmax from J/y g Measure e+e-->J/yX, y(2S)X, search c1X, c2X subtract y(2S) contribution to J/yX for J/ydirectX +momentum spectra +polarization(momentum)

  7. Prompt J/y Results Spectra • softer than expectation for J/y gg • ~ expectation for J/y cc • No peak @ pmax* (from J/y g) Polarization • no significant p* dependence J/y y(2S)

  8. (hep-ex/0205104; 41.8 fb-1(4S), 4.4 fb-1(<4S)) s: predictions vary 0.07 -> few pb •  region: high rate, S/B for • = clean signature for sea-c • high L of B-factory compensates for low e. Outline of analysis • find J/y -> e+e-, µ+µ- a) search for B->J/y{ }: plot “recoil mass” Mr2 = Er2 - pr2 -py Ebeam-Ey -> Mr2 = (Ebeam-Ey)2-py2 resolution improved ~ 2x via constraint: Ey2 - py2 = My2 b) search for associated D*+, D0

  9. a) J/y mass sideband Event selection: Nchg≥5 with J/y mass constraint c’ c0 hc (J/yJ/y forbidden by C)

  10. b) Reconstruct D*+ -> D0π+ {D0->K-π+, K-K+, K-π-π+π+, Ksπ+π-, K-π+π0} net D0 -> K-π+, K-K+

  11. b) Average: Conclusion: Not consistent with NRQCD

  12. Observation of hc’(PRL 89, 102001 (2002); 41.8 fb-1) History Theory: M~3625-3645 MeV/c2 Exp’t: M=3594±5 MeV/c2(Xtal Ball,PRL48,70(1982)) (several unsuccessful attempts to verify) In B decay: B{ } charmonium Unrestricted in J,P,C -> spectroscopy B->hcK observed (CLEO), hc’, hc expected to decay similarly ->search in observed hc channels Outline Search for B->hc’K+, hc’Ks {hc’->KsK-π++c.c.} Reject bg: B->D(Ds)X, K*->Kπ

  13. Observation of hc’ bins of M(KsKπ) Kinematics for final selection: DEE*cand–E*beam0 (E*beams0.5/2) s~13 MeV Mbc (Beam-constrained mass) Mbc(E*beam2-p*cand2 )0.5 |DE|<0.04 GeV ! ! Simultaneous fit, each bin of M(KsKπ): Mbc , DE{5.271 < Mbc < 5.287 GeV/c2} M(hc’)=3654±6±8 Mev/c2 104±14 consistent w theory 39±11 M(hc)=2979.8±1.8 Mev/c2

  14. Charmonia in B decay Test of factorization approximation: for color-suppressed modes } Factorizable ( no gluon req’d) modes dominate Factorization-violating B--> c0K-(PRL88,052001 (2002)) 29.1 fb-1(4S), 2.3 fb-1(<4s) B -> c2X (PRL89,011803 (2002)) 29.4fb-1(4S), 3.0 fb-1(<4s) cf: Conclude: non-factorizable/factorizable=o(1) <- cc0->ππ BR

  15. B->h’K(PLB 517, 309 (2001) 10.4 fb-1(4S) Theory:B(B->h’K+)~(21-53)x10-6 B(B->h’K0)~(20-50)x10-6 Experiment - history: CLEO, first indication of anomalously high B (new physics?) B(B->h’K+)x106 B(B->h’K0)x106 Belle: in h’->hππ, h’-> Consistent with CLEO, somewhat larger than theory->need more data

  16. Summary Belle 1999-2002: rapidly increasing L Large sample of B, c events to test many aspects of hadronic physics Intriguing results: • NRQCD fails to describe •hc’ mass consistent with potential model • factorization approx. fails for B->charmonium • hint of anomalously high rate for B->h’X Next • systematics improving • data - 90 fb–1; increasing - 8617 pb–1/mo • new developments in theory?

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