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The Y(5S) at CLEO

The Y(5S) at CLEO. Introduction Bs Reconstruction at the Y(5S) CLEO PRL 96, 022002 (2006) B Reconstruction at the Y(5S) CLEO PRL 96 152001 (2006) Inclusive Ds production at the Y(5S) CLEO PRL 95 261801 (2005) + update CLEO Conf 06-16

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The Y(5S) at CLEO

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  1. The Y(5S) at CLEO Introduction Bs Reconstruction at the Y(5S) CLEO PRL 96, 022002 (2006) B Reconstruction at the Y(5S) CLEO PRL 96 152001 (2006) Inclusive Ds production at the Y(5S) CLEO PRL 95 261801 (2005) + update CLEO Conf 06-16 Inclusive phi production at the Y(5S) CLEO Conf 06-16 Ian Shipsey Purdue University For the CLEO Collaboration I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  2. Introduction • The Y(5S) discovered by • CLEO & CUSB in 1985. massive enough to decay into : • Knowledge of Bs production at Y(5S) essential for assessing the potential of Bsphysics at a high luminosity e+e collider. • A clean source of BS decays is valuable to interpret New Physics found directly at the LHC. I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  3. Y(5S) Brief History CLEO PRL 54 381, 1985 • CLEO & CUSB scan in 1985 0.07 fb-1 & 0.12 fb-1 taken on peak Y(6S)? Y(5S) CUSB PRL 54, 377, 1985 • CUSB fit to modified • potential model But no conclusive evidence for Bs production at Y(5S) I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  4. Return to Y(5S) New Data CLEO III 2003 0.42 fb-1 at 10881 MeV BELLE 2005 1.86fb-1 at 10869 MeV (Talk of Drutskoy) BELLE June 2006 19 fb-1 at 10869 MeV (to be analysed) Analysis differences between Y(5S) and Y(4S): The ratio of resonance to continuum is larger at the Y(4S) Same continuum data used for both Y(5S) and Y(4S). But continuum data is almost 300 MeV in CME below Y(5S) and is usually taken at different times. So the continuum subtraction becomes a significant systematic error Cross sections measured in 1985 have been re-measured CLEO: (0.301±0.002±0.039) nb BELLE: (0.305±0.002±0.016) nb Excellent agreement I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  5. CLEO Result 1: Observation of the Bs @Y(5S) Exclusive reconstruction of the Bs CLEO PRL 96, 022002 (2006.) • An extension of B meson reconstruction technique used at the Y(4S) MC Case 1 Case 2 Case 3 I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  6. CLEO Result 1: Observation of the Bs @Y(5S) 4 events Y(5S)  Bs* Bs*: 3 BsJ/ , 1 BsJ/. I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  7. 10 events Y(5S)  Bs* Bs*: Bs Ds(*) / (4 Ds modes) I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  8. The center of the signal band for Bs mesons The center of the signal band for ordinary B mesons CLEO Result 2:Ordinary B mesons @ Y(5S) MC • The Y(5S) resonance can decay into a variety of states with ordinary B mesons: • 7 possibilities: Use same analysis techniqiue developed for Bs mesons in previous analysis. Ordinary B decay modes occupy a different region on the ΔE-Mbc plane & have distinct decay modes I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  9. Ordinary B Mesons @ Y(5S) With more BB final states (7) Mbc plane is slightly more complicated. BD(*)(p or r) & B J/y K(*) Data MC I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  10. Ordinary B Mesons @ Y(5S) 1-D projection beam constrained mass with suitable cuts on DE CLEO B*B* Use BD(*)(p or r), B J/y K(*) • Production largest for B*B*, consistent with models • BB/B*B* < 22% @ 90% cl • BB*/B*B* = (24±9±3)% • BS* mass • M(BS*)-M(B*)=(87.6±1.6±0.2) MeV • M(Bs*)=(5411.7 ± 1.6 ± 0.6) MeV • M(BS*)-M(BS)=(45.7±1.7±0.7) MeV consistent, as expected from Heavy Quark Symmetry with • M(B*)-M(B) =45.78±0.35 MeV BBpp BB* BB(*)p BB I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  11. Ordinary B mesons @ Y(5S) Determine yield from BD(*)(p or r) & B J/y K(*) with B invariant mass Total of 53±9 events s=0.177±0.030±0.016 nb, 59% of resonance cross section combine with the sum s= (0.286±0.040) nb saturates (within the stats.) Compare to total cross section Translates to fS=0.41±0.10±0.10 Invariant mass I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  12. Model Dependent BS Fractions, fS • Method use inclusive yield • Choose a particle that has very different decay rates from B & BS • Ex: DS measure measure Model estimate based on quark level diagrams and measured ordinary B decay rates  B(BS→DS X) =(92±11)% I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  13. Result 4 Measurement of fS from Ds Yields -data continuum Y(5S) Y(4S) Y(4S) Branching Fraction Y(5S) x ( |p|/Ebeam ) (CLEO) (Belle) I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  14. Result 4 Measurement of fS Using f Yields • Here we need B(BS→fX) • Use CLEO-c inclusive yields for B(Do→fX)=(1.0±0.10±0.10)% B(D+→fX)=(1.0±0.10±0.20)% B(DS→fX)=(15.1±2.1±1.5)% Preliminary [hep-ph/0605134 ] • From B(B →fX)=(3.5±0.3)%, ascertain that most of f’s arise from B →D & DS→f • Predict that B(BS→fX)=(14.9±2.9)% I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  15. Measurement of fS Using f Yields -data CLEO inclusive f yields, for x<0.5, R2<0.25 Y(5S) Y(4S) Branching Fraction x ( |p|/Ebeam ) I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  16. Measurementof B(Y(5S)  BS(*)BS(*)) Using DS & f Mesons SUMMARY s(e+e-  Y(5S)) = (0.301± 0.002± 0.039)nb [1] CLEO [PRL 95, 261801 (2005)] [2] CLEO [PRL 96 152001(2006)] I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  17. Summary of fSMeasurements Plot: statistical & systematic uncertainties added linearly Average takes into account correlated syst. uncertainties on Y(5S) cross-section model dependencies on Inclusive yields Combine with Belle Plot adapted form Stone SuperB Workshop SLAC 6/2006 I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  18. Summary 1st Observation of the Bs at the Y(5S) and determination of the composition of BsBs final states. Bs*Bs* dominates 1st determination of the composition of ordinary BB final states at Y(5S). B*B*:BB*:BB ~ 3:1:<1, Upper limits for BB ,B(*)B(*)p and BBpp, Bs*Bs BsBs. Both Bs & B compositions consistent with predictions M(Bs*)=(5411.7 ± 1.6 ± 0.6) MeV world’ best measurement. M1 Mass splitting: M(BS*) - M(BS) = (45.7 ± 1.7 ± 0.7) MeV as expected by HQS: Inclusive yields of Ds and phi mesons measured for the first time  Bottom line: between about ¼ (0.07 nb) & 1/3 (0.11 nb) of Y(5S) decays to BS(*) BS(*)These estimates are model dependent and indicate that an extended Y(5S) run at a B factory would be fruitful. Belle results from 1.8/fb run are in broad accord with the above results I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  19. I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  20. Additional Slides I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  21. Result 3 Y5S Y4S I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  22. I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  23. . . . . . . . . . . . . . . . . . . . . . Comparisons with Models Unitarized Quark Model Quark Hybrid Model • UQM predicts DR~0.4, fS=38%, BS*BS* large • QHM predicts DR~0.7, fS=21%, BS*BS* large • Other models: • Martin & Ng, Z Phys. C 40, 133 (1988) • Byers [hep-ph/9412292 Y(5S) Y(5S) I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

  24. Model of DS Production • Must assume knowledge of B(BS→DS X) • Account for fragmentation that reduces DS rate from BS, CLEO & BELLE use same model B(BS→DS X) =(92±11)% I. Shipsey Heavy Quark Physics ICHEP06 7/27/06

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