1. DPF-2006 1 Victor Pavlunin on behalf of the CLEO Collaboration DPF-2006 Results from four CLEO Y (5S) analyses:  Exclusive B s and B Reconstruction at the Y (5S)  Inclusive D s and  Production at the Y (5S) -- ++ K-K- K+K+

2. DPF-2006 2 References: Exclusive measurements:  “Observation of B s Production at the Y (5S) Resonance”, (CLEO collaboration) PRL 96, 022002 (2006)  “Measurements of the Exclusive Decays of the Y (5S) to B Meson Final States and Improved B s * Mass Measurement”, (CLEO Collaboration) PRL 96, 152001 (2006) Inclusive Measurements:  “Evidence for B s (*) B s (*) Production at the Y (5S)”, (CLEO collaboration) PRL 95, 261801 (2005). [Includes a measurement of D s production at the Y (5S)]  “Measurement of B ( Y (5S)  B s (*) B s (*) ) Using  Mesons”, (CLEO Collaboration) hep-ex/0610035. Submitted to PRD. [Includes a measurement of  production at the Y (5S)]

3. DPF-2006 3 Y (5S) Data Samples  CLEO I (1985): 0.12 fb -1  CLEO III (2003): 0.42 fb -1  BELLE (2005): 1.9 fb -1  BELLE (2006): ~20 fb -1  BABAR has not run at the Y(5S) [Note: E CM are different by several MeV for different data sets] The topic of this talk

4. DPF-2006 4 CESR and CLEO  The CLEO detector was developed for B physics at the Y (4S). The CLEO-III configuration: B-field: 1.5 T Gas (drift chamber): He and C 3 H 8 Tracking: 93% of 4 ,  P/P  0.6% for a 1.0 GeV track Hadron particle ID: RICH (80% of 4  ) and dE/dx E/M crystal calorimeter: 93% of 4π,  E/E  2.0% (4.0)% for a 1.0 GeV (100 MeV) photon Muon prop. chambers at 3, 5 and 7 I.  The CLEO experiment is located at the Cornell Electron Storage Ring (CESR) operated in the region of the Upsilon resonances for over 20 years.  In 2003, we started collecting data at the  (3770). Before that, we took a short run at the Y(5S).

5. DPF-2006 5 Introduction: B s at the Y (5S) (1)  The Y (5S) resonance was discovered by CLEO and CUSB at CESR in 1985.  The Y (5S) is massive enough to decay into the following channels:  No evidence for B s production at the Y (5S) was found in 116 pb -1 collected in1985.  Knowledge of B s production at the Y (5S) is important for evaluating the potential of B s physics at a high luminosity e + e  collider (Super- B factory). Results from CLEO III studies of B s production are the focus of this talk. CLEO PRL 54, 381 (1985) Y (5S)

6. DPF-2006 6  There are two papers that measure the hadronic cross section above the Y (4S) resonance: CLEO: PRL 54, 381 (1985) CUSB: PRL 54, 377 (1985)  The cross section above the Y (4S) is described well by the Unitarized Quark Model ( S.Ono et al., Phys.Rev.D 34, 186 (1986) ).  The UQ model predicts: Y (5S)  B * B * or B s * B s *, The B s cross section is  1/3 of the Y (5S) cross section.  ( e + e -  Y (5S))  0.35 nb  Expect  150 K of Y (5S) decays in the CLEOIII 0.42 fb -1 data sample, 1/3 of that are B s (*) B s (*) pairs. Introduction: B s at the Y (5S) (2) E CM (GeV) Curve: UQM Data: CLEO Y (5S)

7. DPF-2006 7 Y (5S) Cross Section Measurements  Count hadronic events at the Y (5S)  Subtract the continuum using data taken below the Y (4S) Scale by ratios of luminosities and E cm 2 Luminosity ratio is a significant source of systematic error since  (Y5S) ~ 0.1  (continuum) and the continuum data are taken 300 MeV below the Y(5S)  Results:  [ Y (5S)]=(0.301±0.002±0.039) nb  Consistent with theoretical predictions Ref: hep-ex/0610035

8. DPF-2006 8 Exclusive B (s) Reconstruction at the Y(5S)

9. DPF-2006 9  An extension of B reconstruction technique used at the Y (4S) is employed to reconstruct B s mesons at the Y (5S): Continuum background suppression variables (e.g., R 2 = H 2 / H 0 )  Three decay channels of the Y (5S) to B s mesons are possible: Decay channel 1: Decay channel 2: Decay channel 3: Overview of the Method (1) MC

10. DPF-2006 10 Overview of the Method (2)  The Y (5S) can decay into a variety of states with ordinary B mesons:  Large background from the continuum ( e + e -  qq ) : A signal band for B mesons A signal band for B s mesons MC [The OFF Y (4S) and  b data are used to model the continuum bkg] [The ON Y (4S) data are used to model B bkg in the B s analysis]

11. DPF-2006 11 B s modes with a J /   Search for very clean modes having very large S/B ratio: B s  J/  , J/   and J/   ’.  The J/  is reconstructed in the  and ee channels. The following channels are used for other particles:   KK,   ,    (  )  +  -.  Expect to find few signal events, assuming branching fractions similar to those for B mesons. In the Y (5S) data, we find: 4 events in the signal box for Y (5S)  B s * B s * : 3 events in B s  J/  1 event in B s  J/  DATA The level of non- B s background is  0.08 events at 68% CL in the B s * B s * signal region. The probability for 0.08 events to fluctuate to 4 events or more is P I  1.6  10 -6 M( B s * ) = 5.4150  0.0018(stat) (GeV)

12. DPF-2006 12 A Signal Event  - - ++ K-K- K+K+

13. DPF-2006 13 B s modes with a D s (*)-  B s  D s (*)  /  with D s modes given in the tables  MC predicts that a total of 10-14 events can be reconstructed in these channels  In the Y (5S) data we find 10 signal candidates ( including background ): The level of background is  1.8 events at 68% CL in the B s * B s * signal region. The probability for 1.8 events to fluctuate to 10 events or more is P II  1.9  10 -5 M( B s * )= 5.4129  0.0012(stat) (GeV) DATA B 0 branching fractions:

14. DPF-2006 14 Results for B s (*) Production  P I and P II are combined to obtain an overall probability for a background fluctuation [ P = (P I P II )(1-ln(P I P II )) ]: P  8  10 -10 (  6  ).  All signal events correspond to B s * B s * production. We set the following limits (90% CL): and  Relating B s branching fractions to B branching fractions, we find: which is consistent with the theory (UQM): 1/3 of 0.30 - 0.35 nb of the total Y (5S) cross-section.  The mass of the B s * meson is measured to be [for more information see: PRL 96, 022002 (2006)]

15. DPF-2006 15 B modes with J /  and D (*)  Modes B  D ( * )  /  and B  J/  K (*) (in total 25 modes):  E (GeV) M bc (GeV) MC Data Note the non-standard definition of  E in these plots (should have the opposite sign)

16. DPF-2006 16 Results for B (*) Production  B * B * is again dominant ( consistent with models ):  (B*B*)/  (BBX) = (74±15±8)%  (BB*)/  (BBX) = (24±9±3)%  (BB)/  (BBX) < 22% at 90% CL  In combination with gives consistent with theory and exper. [for more information see: PRL 96, 152001 (2006)] B*B* BB* BB BB ( * )  BB  (53  9) events

17. DPF-2006 17 Inclusive D s and  Measurements at the Y (5S)

18. DPF-2006 18 Overview of the Inclusive Method  The method relies on the fact that D s (and  ) mesons are produced more copiously in B s decays compared to B decays. Main Analysis Steps:  Measure D s yields ( D s   +,  K + K - ) in bins of x = | P Ds |/ E beam in the continuum, Y (4S) and Y (5S) data.  Measure B ( Y (4S)  D s X ) and B ( Y (5S)  D s X ) by subtracting properly scaled and normalized continuum yields from the Y (4S) and Y (5S) yields  Extract f s according to the equation above and account for systematic errors. measure Model dependent estimate: B ( B s  D s X ) = (92  11) % [ B ( B s   X ) = (15  3) %]

19. DPF-2006 19 Results of the Inclusive D s Method The largest sources of the systematic uncertainty are the uncertainty associated with the luminosity measurements the uncertainty in B ( D s  ). Y(5S) Y(4S) Y(5S) continuum  CLEO inclusive D S yields for x < 0.5 and R 2 <0.25 [for more information see: PRL 95, 261801 (2005)]

20. DPF-2006 20 Results of the inclusive  method  CLEO inclusive  yields for x < 0.5 and R 2 <0.25 Y(5S) Branching Fraction Y(4S) X = |P|/E beam Y(4S) Y(5S) continuum [for more information see: hep-ex/0610035

21. DPF-2006 21 Summary and Conclusions Using 0.42 fb -1 of data at the Y(5S) resonance, we obtain the following results:  First observation of B S production at the Y (5S): ; and limits: and  First study of B production at the Y (5S): ;  Determination of  Estimates of B s production using inclusive measurements of D s and  production at the Y (5S) ( model dependent ): D s production:  production:  Belle ( using the 1.9 fb -1 sample ) confirms CLEO results The Y (5S) resonance is a significant source of B s mesons for a high luminosity e + e - collider

22. DPF-2006 22 Additional Slides

23. DPF-2006 23  Use CLEO-c inclusive yields ( hep-ex/0610008 ) for B ( D o →  X ) = (1.0±0.10±0.10)% B ( D + →  X ) = (1.0±0.10±0.20)% B ( D S →  X ) = (15.1±2.1±1.5)%  Demonstrate that majority of  mesons arise from B  D  and B  D S  .  Predict B ( B S →  X ) = (14.9±2.9)%  Consult hep-ex/0610035 for details Model estimate of B ( B S →  X )