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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+

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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)]

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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

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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).

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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)

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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)

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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

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

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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

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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]

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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)

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

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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:

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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)]

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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)

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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

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

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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) %]

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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)]

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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

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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

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DPF-2006 22 Additional Slides

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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 )

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