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Hadron Physics at the B Factories

Hadron Physics at the B Factories. Brian Meadows University of Cincinnati. Outline. B Factories and Hadron Studies Charm meson spectroscopy Charm Baryons Charmonium and Double Charmonium Summary and Discussion Dalitz Plots ???. B Factory Luminosities.

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Hadron Physics at the B Factories

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  1. Hadron Physics at the B Factories Brian Meadows University of Cincinnati Brian Meadows, U. Cincinnati.

  2. Outline • B Factories and Hadron Studies • Charm meson spectroscopy • Charm Baryons • Charmonium and Double Charmonium • Summary and Discussion • Dalitz Plots ??? Brian Meadows, U. Cincinnati

  3. B Factory Luminosities Peak luminosity 1.001034 cm–2s–1 Integrated luminosity 299 fb–1 Peak luminosity 1.581034 cm–2s–1 Integrated luminosity 488 fb–1 e+ e- (3.1 x 9.0 GeV/c) e+ e- (3.5 x 8.0 GeV/c) 1 fb-1 ~1.1M BB events Brian Meadows, U. Cincinnati

  4. BaBar and Belle e+ (3.5 GeV/c) e- (8 GeV/c) • Main purpose: Study CP violation in asymmetric e+e- (4S)  BB • A major difference between the two detectors is the PID system: • Babar: Dirc ring imaging C • Belle: TOF and Threshold C with aerogel v v Brian Meadows, U. Cincinnati

  5. Fixed Target Experiments Too?Penta-Quark Searches BaBar Belle e-NK 0p Vertices • hep-ex/0507014: • (1540)/(1520) < 2.5% (90% CL) No (1540) pentaquark signal seen: Preliminary e- Be e- Be M (K0p) (GeV/c2) M (K0p) (GeV/c2) Brian Meadows, U. Cincinnati

  6. (Non-B) Hadrons at B Factories? • Cross sections are large Can use “off peak” data • Very high statistics (~1.4 x 106D’s / fb-1). • Also • Relatively small combinatorial backgrounds in e+e- interactions. • Good particle ID. • Detection of all possible final states including neutrals. • Good tracking and vertexing On Off ECM (GeV) Brian Meadows, U. Cincinnati

  7. Hadrons - Friends or Foes? • Hadrons may get in the way of the “really interesting” quark/lepton interactions, but they can also aid in understanding them … … for example, in finding the CKM angles … Brian Meadows, U. Cincinnati

  8. PRD 71: 032005 (2005) 89 fb-1 CKM Angle  and Hadrons • To measure sin 2β - the golden channel is B0 J/Ks • Leads to a four-fold ambiguity in the determination of the angle β. • Babar used B 0 J/K-+ to find sign of cos 2 • An amplitude analysis was made of the K-+ system to determine the relative phase between S- and P-wave contributions to the decay • A clear choice agrees with the LASS data Brian Meadows, U. Cincinnati

  9. M 2+ M 2+ M 2- M 2- CKM Angle g from Direct CP Violationin B§D 0K§ =rb ei ( B§ )x § K0+- § § K0+- § • Angle  relates the two decays B- D 0K-andB-  D 0K- • SupposeD0(D 0) K-(K 0) +- • If CP conserved in D0 decay, Dalitz plot for D0 is identical except that+  - • The final states are indistinguishable • So, the two Dalitz plots interfere Brian Meadows, U. Cincinnati

  10. PRL 95: 121802 (2005) and hep-ex/0504039 205 fb-1 D0 K0+- Dalitz Plot Analysis • Use large available sample of D0 from e+e- cc continuum to determine the Dalitz plot density for D 0 • Two models used: • “Breit-Wigner Isobar model” Requires 13 resonances including “(500)” and “(1000)” • K-matrix model (fit shown) better way to describe the  S-wave – no ’s needed Brian Meadows, U. Cincinnati

  11. DsJ Mesons Brian Meadows, U. Cincinnati

  12. Heavy-Light Systems 2jqLJ  JP • Narrow statesare easy to find. • Two wide states are harder. • Since charm quark is not infinitely heavy, some jq=1/2, 3/2 mixing can occur between the two JP=1+ states. jq = 3/2 2+ small 3P2 D-wave large 1+ 1P1 S-wave L = 1 1+ 3P1 small D-wave jq = 1/2 1P0 0+ large S-wave tensor spin-orbit jq = 1/2 1- small 1S1 L = 0 small 0- 1S0 Expected by quark models To be below D(*)K threshold Brian Meadows, U. Cincinnati

  13. The Ds(2317) and Ds(2460)see PRL 90, 242001 (2003) • When Antimo Palano studied the Ds0 system he found a huge, unexpected peak. There is no signal from Ds+ sidebands. The Ds*!Ds+0 signal is clear too. How did CLEO miss it?! CLEO had discarded All these events. Brian Meadows, U. Cincinnati

  14. hep-ex/0507064 350 fb-1 Mixing in the JP = 1+DsJ(2460) / Ds1(2536) • Belle has analyzed Ds1(2536) decays to D*K to look for an S-wave component. • (In the limit the c quark has infinite mass, the narrow states would decay in pure D-wave) • Angular distribution of + in D*+ system leads to the limits 0.277 < S/(S+D) < 0.955 Indicative of some mixing First time these modes are seen Brian Meadows, U. Cincinnati

  15. New Results onDsJ(*) in e+e− ccfrom Babar hep-ex/0408067 Brian Meadows, U. Cincinnati

  16. p(0) > 400 MeV/c, E > 135 MeV DsJ*(2317)+ Ds+0-g Ds*(2112)+ Ds+  + g Ds+ 0 invariant mass (GeV/c2) 125 fb-1 hep-ex/0408067 Ds+0 Final States • Clear peak from DsJ(2460)+ • DsJ(2460)+ decays entirely through channel Ds*(2112)+ 0 m(Ds+0)= 2.46 GeV/c2 Requires multi-channel analysis DsJ(2460)+: 292  29 events Mass: 2459.1  1.3  1.2 MeV/c2 Brian Meadows, U. Cincinnati

  17. 125 fb-1 hep-ex/0408067 Ds+0 Final States p*(Ds+0) > 3.2 GeV/c p(0) > 400 MeV/c • Clear peak from DsJ*(2317)+ DsJ(2460) “-g” Ds*(2112) “+g” No DsJ(2460)+ Ds+0 DsJ*(2317)+: 1275  45 events Mass: (2318.9  0.3  0.9) MeV/c2 Ds+0 invariant mass (GeV/c2) Brian Meadows, U. Cincinnati

  18. 125 fb-1 hep-ex/0408067 Ds+ Final States p*(Ds+) > 3.2 GeV/c E > 500 MeV Clear peak from DsJ(2460)+ DsJ(2460)+: 509  46 events Mass: 2457.2  1.6  1.3 MeV/c2 DsJ(2460)+ Ds*(2112)+ Ds+ Reflection Background subtracted Ds+  invariant mass (GeV/c2) Compatible with DsJ*(2317)+ JP =0+ Excludes JP=0+ for Ds*(2460)+ Brian Meadows, U. Cincinnati

  19. 125 fb-1 hep-ex/0408067 Ds++ - Final States p() > 250 MeV/c Ds1(2536)+ Clear peaks for both JP=1+ candidates: DsJ(2460)+andDs1(2536)+ DsJ(2460)+ DsJ(2460)+: 67  11 events Mass: 2460.1  0.3  1.2 MeV/c2 Ds+ + - invariant mass (GeV/c2) I-spin conserved BUT OZI suppressed Forbidden for DsJ*(2317)+ JP =0+ Excludes JP=0+ for Ds*(2460)+ Brian Meadows, U. Cincinnati

  20. 125 fb-1 hep-ex/0408067 Ds+± Final States • Test the 4 quark hypothesis for DsJ*(2317)+ and DsJ*(2460)+: • Might expect neutral and doubly-charged partners with similar masses • Look in Ds+± to test this possibility Ds+- p() > 300 MeV/c PRD 68, 054006 Ds++ Neither is seen No clear evidence for exotic nature p() > 300 MeV/c Ds+ ± invariant mass (GeV/c2) Brian Meadows, U. Cincinnati

  21. DsJ(*) in B decays Advantages of exclusive reconstruction: • Kinematic constraints • Backgrounds reduced • Measure of branching fractions • Measure spin of resonances Brian Meadows, U. Cincinnati

  22. PRL 93, 181801 113 fb-1 B  DsJD(*) Decay Signals • Sum of the 4 B modes: Clear signals in 3 DsJ* modes Yield = 88  17 m(DsJ*) = 2317.2  1.3 Yield = 112  14 m(DsJ) = 2458.9  1.5 Yield = 139  17 m(DsJ) = 2461.1  1.6 m(DsJ(*)+) (GeV/c2) MES (GeV/c2) Fit result 1 candidate per event m(DsJ(*)) sidebands Brian Meadows, U. Cincinnati

  23. Values of the branching fractions for the 12 modes: = 0.274 ± 0.045 ± 0.020 Good agreement with prediction (5.08/21.05=0.245) from Bardeen, Eichten, Hill, PRD 68, 054024 (2003) PRL 93, 181801 113 fb-1 Results Comparable to B D* modes! Brian Meadows, U. Cincinnati

  24. PRL 93, 181801 113 fb-1 Helicity Analysis • Two body decay BDDsJ forces DsJ to be aligned (if it is not a scalar) • Use low background mode: B  DsJ(2460)+ D, DsJ(2460)+  Ds+ • 5 m(Ds) fits for different cos h regions • Good agreement with JP = 1+ J = 1 J = 2 DsJ(2460)+ DsJ  h B Ds D Brian Meadows, U. Cincinnati

  25. hep-ex/0507064 350 fb-1 B DsJK and B DsJ • B 0 Ds(J)K - is especially interesting none of the final state quarks (cuss) are in the initial B (bd) meson. • Decay ofB 0 DsK –has been measured(3.8 § 1.0) x 10-5(average of Babar and Belle) • B 0 Ds(J)- is expected to be small. Brian Meadows, U. Cincinnati

  26. B0 DsJ(2317)+K - Compare these with Br{B0 Ds+K-} = (5.1 ± 1.3) x 10-5 (average of Babar and Belle) B0 DsJ(2460)+K - Naively expect them to be the ~ same C.-H. Chen, H.-n Li, Phys. Rev. D 69, 054002 (2004) -0.11 Brian Meadows, U. Cincinnati

  27. Selex reported the observation of a new narrow charm-strange meson : the D+sJ (2632)→ D+s, D0K+ SELEX: Phys. Rev. Lett. 93:242001 (2004) Search for DsJ(2632) N(Ds+) = 544  29 N(h) = 5087  863 uncorrelated h SELEX Ds+h D0K+ SELEX Brian Meadows, U. Cincinnati

  28. hep-ex/0408087 126 fb-1 Search for DsJ(2632) BaBar sees no evidence for production of DsJ(2632) inDs+h , D0K+norD*+K0sin 126 fb-1 of data N(Ds+) = 196000 N(h) = 3900 correlated h Ds2(2573)+ Ds1(2536)+ Ds+h D0K+ D*K0 p* > 4.0 GeV/c D0K- Fit after 2D bckg subtr. Brian Meadows, U. Cincinnati

  29. Charm Baryons Brian Meadows, U. Cincinnati

  30. hep-ex/0507011 230 fb-1 Decay Branching Ratios of c • Clear c0 signals are seen in - + and -K-++ decay modes • Hyperon events are reconstructed in the decay chains - --  K -  p -  p - Brian Meadows, U. Cincinnati

  31. hep-ex/0507011 230 fb-1 Production of c Kinematic region allowed for B decay First evidence for c in B decay Brian Meadows, U. Cincinnati

  32. hep-ex/0507011 230 fb-1 Decay Branching Ratios of c • c0 signals are seen in - K+ and -+ decay modes (c0 - K+ ) / (c0 -+)= 0.294 ± 0.018 (stat) ± 0.016 (sys) Previous Best: 0.50 ± 0.21 (stat) ± .05 (sys) (9 evs CLEO) -+ -K+ Brian Meadows, U. Cincinnati

  33. Production of c0 On-resonance 0c in B decay Off-resonance PRL 95:142003 (2005) 116 fb-1 B(Bc0X) × B(c0−+) = (2.11 ± 0.19 ± 0.25) × 10−4 (e+e-c0X) × B(c0−+) = (388 ± 39 ± 41) fb at 10.58 GeV/c2 Brian Meadows, U. Cincinnati

  34. hep-ex/0507009 232 fb-1 Precision Measurement of c Mass • Important measurement • most charm baryon masses measured relative to this • Method: • Choose decay modes with small Q-value/large BR: c K+Ks0and0K+Ks0 • Estimate / adjust major systematic uncertainties in: • Material audit – determine  and K0 mass vs. decay path length • Magnetic field – determine  and K0 mass vs. momentum in lab. • Much larger control samples: • c+ pK-+ 1.5 x 106 evs. • c+  pK0 2.4 x 105 evs. Q = 177.8 MeV/c2 4627§ 84 events Q = 100.9 MeV/c2 264§ 20 events Brian Meadows, U. Cincinnati

  35. Combined measurement : m(Lc) = 2286.46  0.14 MeV/c2 hep-ex/0507009 232 fb-1 Results Large Q • Most precise measurement of charm mass to date • Approximately 4 x more precise than Current PDG value: 2284.9 § 0.6 MeV/c2 and about 2.5  higher Brian Meadows, U. Cincinnati

  36. hep-ex/0507011 125 fb-1 Some Branching Fractions of c+ • Most decay branching ratios in the PDG have typically 40% uncertainties • Few Cabbibo suppressed rates observed are p (CLEO), 0K+ and K+ (Belle) • Babar has new measurements on several Cabbibo suppressed modes with uncertainties at the ~10% level •  modes are normalized to + and 0 modes to 0+ modes c+ + c+0+ c+ 0+ Brian Meadows, U. Cincinnati

  37. Results : Ratios of Branching Fractions with Respect to CF C+ + Cabibbo-suppressed Cabibbo-allowed In PDG ratios of Branching Fractions are with respect to  C+ pK-+ Brian Meadows, U. Cincinnati

  38. PRL 94, 122002, 2005 350 fb-1 p Observation of New Sc Triplet Tentative assignment to JP = 3/2 - Brian Meadows, U. Cincinnati

  39. Scanning the e+e- Energy Brian Meadows, U. Cincinnati

  40. New Parameters for the . • JPC=1-- resonances can be probed using formation processes e+e- g*  X Can measure MX, GX, line shape and e+e- coupling • Results from PEP2 beam energy scans: PRD in press (hep-ex/040525) Brian Meadows, U. Cincinnati

  41. ISR Studies • Wider energy range covered by capitalizing on ISR: Reconstruct the ISRphoton Energy E*angle wrt e- *in e+e- CMS • Good point-to-point systematics • Poorer resolution on energy scale • R must still be JPC=1-- • Cross-section measured as fn of s0=mR2: R Brian Meadows, U. Cincinnati

  42. ISR Production of pp Pairs • The reaction e+e- gISRg*  ppISRis used to provide information on the electric and magnetic moments of the produced pp system. • For * >> me / \/s • The pp cross-section is where Magnetic Electric form-factor Brian Meadows, U. Cincinnati

  43. Preliminary 240 fb-1 Proton Form-Factor (FF) Very strong variation near threshold confirmed • For comparison with previous measurements, |GE| ¼ |GM| is assumed. • FF and  (e+ e- pp) measured from threshold to 4.5 GeV/c2 • Extending range of previous measurements • Covers several decades • Excellent point-to-point precision • Observe clear dips at ~2.25 and at ~3 GeV/c2 • Dips also seen in cross-section  (e+ e- pp). pQCD predicts fall off /s(s’)/s’2 Brian Meadows, U. Cincinnati

  44. Preliminary 240 fb-1 E/M Ratio RG = |GE|/|GM| p • Most previous measurements assumed RG = 1.0 • Babar results clearly show: • RG > 1.0 at low mass • RG» 1.0 above 2.5 GeV/c2 p pp in e+e- CMS GE GM cos p Brian Meadows, U. Cincinnati

  45. Charmonium & Double Charmonium Brian Meadows, U. Cincinnati

  46. Charmonium B-factories have made major contributions to understanding of the cc system: • Below DD threshold one of two missing statesc0(21S0) was found by Belle in B decay, confirmed by Babar in 2 interactions At 3630 – about 40 MeV/c2 above where it was formerly thought to be • Above DD threshold there are five, new states, some of which are puzzling X(3872), X(3940), Y(3940), Z(3930), Z(4260) • Also find evidence for mysterious large X-section for production of double charmonium Brian Meadows, U. Cincinnati

  47. Double Charmonium Production Study double charmonium in e+e- annihilation }C=-1 }C=+1 c , c , c(2S) J/, (2S) Theorists Predict the cross sections of the two processes to be compatible G. T. Bodwin, E. Braaten & J. Lee PRD67, 054023 (2003) Brian Meadows, U. Cincinnati

  48. hc cc0 hc(2S) 155 fb-1 Double Charmonium Production e+e- J/ + Mrecoil • Originally seen by Belle with 45 fb -1 sample Phys. Rev. Lett. 89, 142001 (2002). • Confirmed by BaBar at 124 fb -1 Phys.Rev.D72:031101 (2005). • BaBar also Measure M = mc(1S) - mc(1S) = 660.2§ 6.8-7.6+7.1 MeV/c2 • No evidence for e+e-  J/ J/ production in either experiment Phys.Rev.D72:031101 (2005) 124 fb-1 Phys.Rev.D70:071102,2004 Brian Meadows, U. Cincinnati

  49. Theoretical Comparison with Babar/Belle • Babar and Belle measure s(e+e- J/y cc) xB(cc  > 2 charged hadrons) NOTE – theoretical calculations do not include Br for decay to 2 charged tracks Phys.Rev.D70:071102,2004 Belle finds angular distributions also favour single * and dis-favour color singlet cc gg production S.J. Brodsky, A.S. Goldhaber and J. Lee, Phys. Rev. Lett. 91, 112001 (2003) Brian Meadows, U. Cincinnati

  50. Belle also observes e+e- (2S) + cc • Cross-sections are similar to those for J/ + cc • No evidence for e+e-y(2S) + cc (C=-1) either hc cc0 hc(2S) 155 fb-1 Phys. Rev.,D70, 071102 (2004) Brian Meadows, U. Cincinnati

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