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Sep. 29, 2006 Henry Band - U. of Wisconsin 1 Hadronic Charm Decays From B Factories Henry Band University of Wisconsin 11th International Conference on B Physics at Hadron Machines Oxford, Sept. 25-29, 2006
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Sep. 29, 2006 Henry Band - U. of Wisconsin 2 Talk Outline Strange charmed mesons D sJ (2860) + D sJ (2700)+ D s2 (2573) + D s1 (2536) + D s1 (2460) + D s0 * (2317) + D s * (2112) + Abs. Branching Fractions D s + → K + K - + D s + → + Branching Fractions D + → + 0 D + → K + 0 D 0 → - + 0 D 0 → K - K + 0 Charm Baryons c (2940) Λ c (2880) + c * Ξ c (2980) + Ξ c (3077) +
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Sep. 29, 2006 Henry Band - U. of Wisconsin BaBar and Belle e + e - cc continuum 1.3 nb Off and on peak (4S) 30% more cc than bb b c Cabbibo favored Peak luminosity 1.21 10 34 cm –2 s –1 Integrated luminosity 390 fb –1 Peak luminosity 1.65 10 34 cm –2 s –1 Integrated luminosity 630 fb –1 Sep. ab-1 integrated flux combined B Factories C
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Sep. 29, 2006 Henry Band - U. of Wisconsin 4 D s family mesons Observation by BaBar, Cleo, and Belle of D sj (2317) and D sj (2460) at lower masses than expected by HQS theories raised questions about cs meson spectroscopy D s mesons or exotics (4 quarks)? Gather more info Masses Width Decay modes Branching fractions Other decay modes New states D sJ * (2317) D sJ (2460) DsDs Ds*Ds* D s1 (2536) D s2 (2573) Q q
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Sep. 29, 2006 Henry Band - U. of Wisconsin 5 Spin Analysis D sJ * (2317) D sJ (2460) DsDs Ds*Ds* D s1 (2536) D s2 (2573) Q q J = 0: 2 /d.o.f = 3/8 J = 1: 2 /d.o.f = 38/8 J P = 0 + D sJ (2317) → D s π 0 Belle-CONF-0461 (2004) 274M BB J = 1: 2 /d.o.f = 4/8 J = 2: 2 /d.o.f = 89/8 J P = 1 + D sJ (2460) → D s γ B decays
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Sep. 29, 2006 Henry Band - U. of Wisconsin 6 Survey of Decays to D s Final States Select D s → K + K - + Require K + K - or K*(892 ) K - + p*> 2.2 GeV Combine with , K, , 0 Tighter cuts on p* and kinematics to select intermediate states (D s (*), D sJ (2317)) Subtract D s X bkg using D s mass sidebands Fit mass spectrum signal Breit-Wigner resolution Combinatorial background include pdfs for possible reflections from other cs states No cut Cuts on intermediate states sidebands signal ~4 10 5 D s + Hep-ex 0604030
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Sep. 29, 2006 Henry Band - U. of Wisconsin 7 D s D s * (2112), D s1 (2460) D s - Combine D s with ‘s > 150 MeV/c Raise E > 500 MeV/c Fit signal peak + sum oBkgd oD s0 * (2317) D s + ) oD s1 (2460) D s * (2112) + ) 232 fb -1 D s1 (2460) + D s + D s sidebands N=920±60 Bkgd. subtracted Hep-ex 0604030 D s + invariant mass (GeV/c 2 ) D s * (2112) + N= 75,000
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Sep. 29, 2006 Henry Band - U. of Wisconsin 8 D s D s0 * (2317) D s + 0 invariant mass (GeV/c 2 ) Combine D s with 2 ‘s consistent with Fit D s + 0 mass spectrum to D s0 * (2317) D s + D s1 (2460) D s + D s * (2112) D s + Reflections from D s * (2112) D s + (+ ) D s1 (2460) D s * (2112) + (- ) Combinatorial bkgd 232 fb -1 D s0 * (2317) + Hep-ex 0604030 N= 26,500
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Sep. 29, 2006 Henry Band - U. of Wisconsin 9 D s D s D s D s1 (2460) D s 0 Assume D s1 (2460) D s *(2112) + 0 Require 2092< m(D s MeV/c Fit signal + reflections D s 0 0 no signal D s no signal 232 fb -1 D s sidebands Light shade: D s * (2112) reflection Dark shade: D sJ * (2317) reflection N=560±40 Preliminary Hep-ex 0604030 D s 0 D s1 (2460) + D s + 0 invariant mass (GeV/c 2 )
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Sep. 29, 2006 Henry Band - U. of Wisconsin 10 D s ±, D s D s1 (2460) + D s1 (2536) + Look for isospin partners D s + - : no signal D s + + : no signal D s + - : no D sJ * (2317) Strong signals D s1 (2460) + D s1 (2536) + D s + - 232 fb -1 D s1 (2536) + D sJ (2460) + Hep-ex 0604030 D s + - D s + + D s + + invariant mass (GeV/c 2 )
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Sep. 29, 2006 Henry Band - U. of Wisconsin 11 D 0 K +, D + K 0 s - D s2 (2573) +, D sJ (2860) +, X(2690) + Look for new states in continuum above DK mass Cuts on D 0(+) and K s reconstructed masses a) D 0 K - + (950,000) b) D 0 K - + 0 (790,000) c) D + K - + + (430,000) Hep-ex 607082 D+D+ D0D0 D0D0 232 fb -1
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Sep. 29, 2006 Henry Band - U. of Wisconsin 12 New States - D sJ (2860) +, X(2690) + (?) New resonance at 2.86 GeV/c 2 Broad state at 2.69 GeV/c 2 Hep-ex 0607082 Combined modes bkgd subtracted D sJ (2860) + D s2 (2573) + invariant mass (GeV/c 2 ) D 0 K - + D 0 K - + 0 D + K - + +
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Sep. 29, 2006 Henry Band - U. of Wisconsin 13 D sj Production in B decays D sj production in several modes BELLE has observed D sj production in several modes B DD sj (2317) or DD sj (2460) Established spinsEstablished spins B K - D sj (2317) or K - D sj (2460) B + → D 0 D 0 K + S = 399 ± 40 S/B ~ 0.3 Dalitz plot and mass projections - different from 3-body phase space Belle-CONF-0643 (2006) 447M BB __ _ _ _ +
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Sep. 29, 2006 Henry Band - U. of Wisconsin 14 B+→D0D0K+B+→D0D0K+B+→D0D0K+B+→D0D0K+ Contributions from several sources Is D sJ (2700) = X(2690) ? Belle-CONF-0643 (2006) 447M BB ■ B + →D 0 D sJ (2700) ■ B + →ψ(3770)K + ■ B + →ψ(4160)K + ■ B + →D 0 D 0 K + NR ■ threshold comp J=0 2 /ndf = 185/5 J=1 2 /ndf = 7/5 J=2 2 /ndf = 250/5 J P = 1 - ■ ψ(4160) reflection Spin Analysis
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Sep. 29, 2006 Henry Band - U. of Wisconsin 15 D *+ K 0 s - D s1 (2536) + D *+ D 0 + D 0 K - + D 0 K - - + + Charged tracks = good mass resolution Low Q – close to threshold Hep-ex 0607084 First width measurement !
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Sep. 29, 2006 Henry Band - U. of Wisconsin 16 D sJ (2700) m= 2715 ± 11 +11 -14 Mev/c 2 = 115 ± 20 +36 - 32 MeV /c 2
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Sep. 29, 2006 Henry Band - U. of Wisconsin 17 Branching Fraction D s + → K + K - + Identify two body D s1 D s * Reconstruct 1 side (D s1 (2536) or D s *) Recoil mass is M recoil = √((√s-E (D s1 )) 2 - p 2 (D s1 )) Measure D s * peak or D s1 → Ds → Ds → K + K - + → D* 0 K + → D* + K s 0
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Sep. 29, 2006 Henry Band - U. of Wisconsin 18 Need further BKgd suppression so use cascade decays on both sides (not just tag) Require additional with D s1 + tag (D s * + → D s + Or K with D* s tag recoil (D s1 ) = M recoil (D s1 ) - M recoil (D s1 ) B(D s + → K + K - + ) = 4.1 ± 0.4 ± 0.4% PDG 2006 5.2 ± 0.9% Branching Fraction D s + → K + K - + D* s tag D s1 tag Belle-CONF-0612 (2006) D s * + → D s + D s * + → D s + recoil (D s *K) GeV/c recoil (D s1 ) GeV/c
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Sep. 29, 2006 Henry Band - U. of Wisconsin 19 BB sample with one B fully reconstructed Other B D ( * )+,0 X Observe D s + and D sJ (2460) signals in the recoil mass, m X Abs. BF’s for D s + ( + ) and D sJ (2460) e-e-e-e- D*D*D*D* e+e+e+e+ B reco B signal D* X Hep-ex 0605036 Fitting the different modes and combining with previously measured branching ratios PDG
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Sep. 29, 2006 Henry Band - U. of Wisconsin 20 Branching Fractions - D + → + 0, K + 0 Improved BF measurements benefit D mixing analyses Measure BF relative to D + → K - + + Reconstruct D + → h + 0 Require D* + → D + 0 p*(D*) > 2.9 GeV/c Use m sidebands to estimate peaking background Efficiencies 5.9-8.5% Sideband region Signal region MC Peaking bkg. from sideband fit MC
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Sep. 29, 2006 Henry Band - U. of Wisconsin 21 Fits Yield from un-binned maximum likelihood fits D + → + 0 D + →K + 0 D + →K - + + Using BF(D + K - + + ) = (9.4 0.3)x10 -2 from CLEO-C & PDG 124 fb -1 First Observation >6.5 D+→K+0D+→K+0 D+→+0D+→+0 ref: D + →K - + + BF(D + + 0 )/BF(D + K - + + ) = BF(D + K + 0 )/BF(D + K - + + ) = BF(D + + 0 )=( 1.25 0.10 0.09 0.04(ref) ) 10 -3 BF(D + K + 0 )=( 2.52 0.47 0.25 0.08(ref) ) 10 -4 Hep-ex 0605044
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Sep. 29, 2006 Henry Band - U. of Wisconsin 22 Cabibbo suppressed 2 body decays of D 0 show anomalous suppression of D 0 - + versus D 0 K - K + (~1/3) Three body decays are poorly measured Reconstruct D *+ → D 0 + m = m(D *+ ) - m(D 0 ) Fit K - + 0 reflection in the - + 0 and K - K + 0 distributions Recover non-uniform reconstruction efficiency weighting events with: W = 1/efficiency no assumptions on Dalitz plot structure Branching Fractions - D 0 → - + 0, K - K + 0 D 0 → K - + 0 D0→ -+0D0→ -+0 D 0 → K - K + 0 Belle ± ± Hep-ex 0608009 Belle-CONF-0608 (2006) 232 fb - 1
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Sep. 29, 2006 Henry Band - U. of Wisconsin 23 Charm Baryon States J P =3/2 + (L=0) J P =1/2 + (L=0) Strangeness Charm Isospin Most C = 1 baryon ground states have been observed (except *c) L > 0 states now being seen C = 2 QQq candidates observed by SELEX (ccd)+ c + K - + (ccu)++ c + K - cc + p D + K - C= 1
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Sep. 29, 2006 Henry Band - U. of Wisconsin 24 c (2940) p D 0 Search in continuum cc pD 0 modes (D 0 K - K - ) Observe previously reported Λ c (2880) + (was observed in c by CLEO ) M = 2881.9±0.1±0.5 MeV/c 2 Γ = 5.8±1.5±1.1 MeV New state Λ c (2940) + M = 2939.89±1.3±1.0 MeV/c 2 Γ = 17.5±5.2±5.9 MeV Confirmed by BELLE in Λ c --> c First example of a charm baryon decay to a charm meson No isospin partners seen in D + p so both Λ c not c Λ c (2880) + Λ c (2940) + Wrong sign D 0 p Hep-ex 0603052 124 fb -1
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Sep. 29, 2006 Henry Band - U. of Wisconsin 25 First Observation of c * (css) c Reconstruct c 0 → a) - + ( - → K - ) 156 +/- 15 events b) - + 0 ( - → K - ) 92 +/- 26 c) - + - + ( - → K - ) 23 +/- 10 d) - - + + - → K - ) 34 +/- 15 Combine with MeV) Plot M( c – M c + M c PDG Combined yield 105 ± 21 ± 6 M = M( c – M c = 70.8 ± 1.0 ± 1.1 MeV Theoretical predictions 50 – 73 MeV Hep-ex 0608055 124 fb -1 M( c – M c + M c PDG GeV/c 2
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Sep. 29, 2006 Henry Band - U. of Wisconsin 26 Search for Doubly Charmed Baryons SELEX reported evidence for cc in c + K - + ( + ), D + p K - Babar has looked for similar decays cc +(+) c + K - + ( + ) c c +(+) c 0 + ( + ) Belle searched cc +(+) c + K - + No evidence despite >10 6 c in B factories SELEX(1630 c ) Λ c + K – π + p*> 0 GeV/c Λ c + K – π + p*>2.3 GeV/c Λ c + K – π + π + p*>2.3 GeV/c Λ c + K – π + π + p*> 0 GeV/c Hep-ex 0605075 124 fb -1
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Sep. 29, 2006 Henry Band - U. of Wisconsin 27 Observation of Ξ c (2980) + and Ξ c (3077) + Look for decays to Λ c + K - π + No peaks in the wrong sign distribution No peaks in the side band Also seen in the isospin partners Λ c + →pK - π + Mass(Λ c + K - π + ) Λ c + →pK + π - Mass(Λ c + K S π - ) hep-ex/0606051, Ξ c (2980) and Ξ c (3077) excited charm strange baryons. Belle Hep-ex 0607042
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Sep. 29, 2006 Henry Band - U. of Wisconsin 28 Summary Large B factory charm samples still producing new charm meson and baryon discoveries D sJ (2860) + D sJ (2700)+ Plus refined masses, widths, BFs on previously discovered states But no double charm Can expect much more in the coming years c (2940) Λ c (2880) + c * Ξ c (2980) + Ξ c (3077) +
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