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Heavy Quark Production and Decay in the Upsilon region: Results from Belle Kay Kinoshita University of Cincinnati Belle Collaboration Hadronic physics in the Upsilon regionHadronic physics in the Upsilon region Belle and KEKB Selected Results:Selected Results: Prompt J/ and double charm production Prompt J/ and double charm production Observation of c ’ Observation of c ’ Production of charmonia in B decay Production of charmonia in B decay Rate of ’ from B decay Rate of ’ from B decay Summary Summary 5th International Conference on Quark Confinement, Gargnano, Italy, September 10-14, 2002
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2 Heavy quarks in the region in cms, E c =E e, ~1 nb in cms, E B =E e, ~1 nb } B { } meson b c Well-defined (& measureable!) production rate, energy most c-hadrons have p>(kinematic limit for b->c) At Belle, ∫ L (4S)dt/∫ L (<4S)dt~0.10 BB threshold
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3 Beams: KEKB E* beam ) = 2.6 MeV IP size = 77µm(x) x 2.0µm(y) x 4.0mm(z) L max = 7.4 X 10 33 cm –2 s –1 (design: 1x10 34 ) Data (6/1999–7/2002) L dt = 89.6 fb –1 @ (4S), 9.0 fb –1 off (~9x10 7 B, c events) e – 8.0 GeV e + 3.5 GeV 22 mr = 0.425
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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
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5 Belle Collaboration 274 authors, 45 institutions many nations many nations
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6 Prompt J/ production (PRL88, 052001 (2002)) 29.4 fb -1 (4S)+3.0 fb -1 (<4S) Test of NRQCD (explains (2S) excess @ FNAL ): e + e - -> J/ gg (dominant) + J/ g + J/ cc (~10%) Predict ~0.8-1.7 pb, peak @ p max from J/ g Measure e + e - ->J/ X, (2S)X, search c1 X, c2 X subtract (2S) contribution to J/ X for J/ direct X +momentum spectra +polarization(momentum)
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7 Prompt J/ J/ (2S) Results Spectra softer than expectation softer than expectation for J/ gg ~ expectation for J/ cc ~ expectation for J/ cc No peak @ p max * (from J/ g) No peak @ p max * (from J/ g)Polarization no significant p* dependence no significant p* dependence
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8 region: high rate, S/B for region: high rate, S/B for = clean signature for sea-c = clean signature for sea-c high L of B-factory compensates for low . high L of B-factory compensates for low . Outline of analysis find J/ -> e + e -, µ + µ - find J/ -> e + e -, µ + µ - a) search for B->J/ { }: plot “recoil mass” a) search for B->J/ { }: plot “recoil mass” M r 2 = E r 2 - p r 2 -p E beam -E ->M r 2 = (E beam -E ) 2 -p 2 ->M r 2 = (E beam -E ) 2 -p 2 resolution improved ~ 2x via constraint: E 2 - p 2 = M 2 resolution improved ~ 2x via constraint: E 2 - p 2 = M 2 b) search for associated D *+, D 0 b) search for associated D *+, D 0 (hep-ex/0205104; 41.8 fb -1( 4S), 4.4 fb -1 (<4S)) : predictions vary 0.07 -> few pb
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9 a) J/ mass sideband with J/ mass constraint Event selection: N chg ≥5 (J/ J/ forbidden by C) cccc c’c’c’c’ c0
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10 b) Reconstruct D *+ -> D 0 π + {D 0 ->K - π +, K - K +, K - π - π + π +, K s π + π -, K - π + π 0 } net D 0 -> K - π +, K - K +
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11 b) Average:Conclusion: Not consistent with NRQCD
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12 Observation of c ’ (PRL 89, 102001 (2002); 41.8 fb -1 ) } charmonium Unrestricted in J,P,C -> spectroscopy B-> c K observed (CLEO), c ’, c expected to decay similarly ->search in observed c channels ->search in observed c channelsOutline Search for B-> c ’K +, c ’K s { c ’->K s K - π + +c.c.} Reject bg: B->D(D s )X, K * ->Kπ History Theory:M~3625-3645 MeV/c 2 Exp’t: M=3594±5 MeV/c 2 (Xtal Ball, PRL48,70(1982)) (several unsuccessful attempts to verify) B{ In B decay:
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13 Kinematics for final selection: E E* cand –E* beam 0 (E* beam s 0.5 /2) ~13 MeV M bc (Beam-constrained mass) M bc (E* beam 2 -p* cand 2 ) 0.5 bins of M(K s Kπ) Simultaneous fit, each bin of M(K s Kπ): M bc, E{5.271 < M bc < 5.287 GeV/c 2 } Observation of c ’ 104±14 39±11 M( c )=2979.8±1.8 Mev/c 2 M( c ’)=3654±6±8 Mev/c 2 | E|<0.04 GeV ! ! consistent w theory
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14 Charmonia in B decay } Factorizable ( no gluon req’d) modes dominate modes dominate Factorization-violating B - -> c0 K - (PRL88,052001 (2002)) 29.1 fb -1 (4S), 2.3 fb -1 ( c0 K - (PRL88,052001 (2002)) 29.1 fb -1 (4S), 2.3 fb -1 (<4s) B -> c2 X (PRL89,011803 (2002)) 29.4fb -1 (4S), 3.0 fb -1 ( c2 X (PRL89,011803 (2002)) 29.4fb -1 (4S), 3.0 fb -1 (<4s) cf: cf: Conclude: non-factorizable/factorizable=o(1) Test of factorization approximation: for color-suppressed modes ππ BR ππ BR
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15 B-> ’K (PLB 517, 309 (2001) Theory:B(B-> ’K + )~(21-53)x10 -6 B(B-> ’K 0 )~(20-50)x10 -6 Experiment - history: CLEO, first indication of anomalously high B (new physics?) B(B-> ’K + )x10 6 B(B-> ’K 0 )x10 6 Belle: in ’-> ππ, ’-> 10.4 fb -1 (4S) Consistent with CLEO, somewhat larger than theory->need more data
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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 NRQCD fails to describe c ’ mass consistent with potential model c ’ mass consistent with potential model factorization approx. fails for B->charmonium factorization approx. fails for B->charmonium hint of anomalously high rate for B-> ’ X hint of anomalously high rate for B-> ’ XNext systematics improving systematics improving data - 90 fb – 1 ; increasing - 8617 pb – 1 /mo data - 90 fb – 1 ; increasing - 8617 pb – 1 /mo new developments in theory? new developments in theory?
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