evidence for b s in 5s at cleo and 4s studies at babar n.
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Evidence for B s in  (5S) at CLEO and  (4S) Studies at BaBar

Evidence for B s in  (5S) at CLEO and  (4S) Studies at BaBar

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Evidence for B s in  (5S) at CLEO and  (4S) Studies at BaBar

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  1. Evidence for Bs in (5S) at CLEO and (4S) Studies at BaBar Jianchun Wang Syracuse University ICHEP’04 August 16-22, 2004, Beijing

  2. (5S) Study at CLEO • CLEO studies Bs in both inclusive and exclusive modes. • Data was taken with the CLEO III detector. Jianchun Wang

  3. CLEO PRL 54, 381 (1985) (5S) A Brief Introduction of (5S) • CLEO & CUSB observed (5S) in 1985. M = 10.8650.008 GeV G = 11013 MeV s((5S))~0.35 nb, ~1/10s(cont). • The composition of the (5S) needs to be investigated. In PDG only e+e- mode is quoted. • Dominant hadronic decay modes: (M(5S)-2MB=307MeV): BB, BB*, B*B*, BBπ, BB*π, B*B*π, BBππ (& c.c.). (M(5S)-2MBs=126MeV): BsBs, BsBs*, Bs*Bs*. • CUSB studied Doppler effect of photon in B(s)*B(s)*g. • CLEO studied: the shape of the lepton spectrum, inclusive particle yield and exclusive Bs reconstruction. • With 116 pb-1 data there is no strong conclusion on Bs production. Jianchun Wang

  4. R DR DR Energy (GeV) Model Predictions • The hadronic cross section in the Upsilon region is well described by the Unitarized Quark Model (UQM), which is a coupled channel model (ref: S. Ono et al, PRL55, 2938(1985)). • The UQM predicts that the Bs(*)Bs(*) production ~ 1/3 of the total (5S) cross section. And (5S) decays are dominated by B*B* and Bs*Bs*. • Other models predict a smaller (5S)Bs*Bs* component. Jianchun Wang

  5. (5S) data B(s) Ds+ X, Ds+ fp+,fK+K- Dfp Dsfp (4S) data Dfp Dsfp M(K+K-p+) (GeV) The Inclusive Channel • Expect much more Ds in (5S) decays than in (4S) decays: • B (BDsX) ~ (10.52.6)% • B (BsDsX) ~ 100% • The (5S), (4S), and continuum data are analyzed to estimate contributions from different sources. In (5S) and (4S) samples ~20% of reconstructed Ds come from continuum. • Ds yield is measured in different x=|p|/Ebeam intervals. • Reconstruction efficiency ~30%. Jianchun Wang

  6. (4S) (5S) NDs/N(4S)(104) NDs/N(5S)(104) |P| / Ebeam |P| / Ebeam Ds Production in (4S) & (5S) Decays Continuum subtraction and efficiency correction, no B correction in plots Preliminary B((4S)DsX) = (22.30.75.7)% B(BDsX) = (11.10.42.9)% PDG (10.52.6)% B((5S)DsX) = (55.05.217.8)% B((5S)DsX)/B((4S)DsX)=2.50.30.6 The systematic error is dominated by B (Dsfp+) and number of (5S) events. Jianchun Wang

  7. NDs/N(5S)-(NDs/N(4S)((104) |P| / Ebeam Evidence of Bs in (5S) Decays Bs decay modes are analogous to the corresponding B decay modes. A model estimate gives (ref: ICHEP04  ABS11-0778 ) B (BsDsX) = (9211)%. Knowing Ds production rate in (5S), B, and Bs decays  B ((5S)Bs(*)Bs(*))= (2139)% consistent with phenomenological predictions. Significant excess of Ds at (5S)  Evidence of Bs production at (5S) Preliminary Jianchun Wang

  8. Ebeam – Ecandidate (GeV) Mbc (Bs candidate) (GeV) Mbc (Bs candidate) (GeV) Exclusive Bs Reconstruction • The B reconstruction techniques used at (4S) are employed to reconstruct Bs from (5S): • Three sources of Bs produce three distinct distributions. B (Bs*Bsg) ~100% MC Jianchun Wang

  9. BsJ/ f//, J/+-, e+e- f  K+K-,   p+p-, gg BsDs(*) p-/r-, Ds*Dsg DsK+K0,K+K*0,fp+, fr+ Ebeam – Ecandidate (GeV) Ebeam – Ecandidate (GeV) Mbc (Bs candidate) (GeV) Mbc (Bs candidate) (GeV) Exclusive Bs Signals At (5S) Preliminary Nsignal = 4, Nbkg  0.1 Nsignal = 8, Nbkg  1 (5S) decay to Bs(*)Bs(*) is dominated by Bs*Bs* mode. Jianchun Wang

  10. (4S) Studies at BaBar EMC DIRC e+ (3.1GeV) DCh e-(9 GeV) SVT • Three (4S) scans and one (3S) scan are used in the measurement of the (4S) resonance parameters. • 81.7 fb-1(4S) data are used in the measurement of B((4S)B0B0). Jianchun Wang

  11. Measurement of (4S) Parameters • The current mass and width of (4S) are with large uncertainty. It can be improved. • The (4S) resonance parameters can be determined by measuring the energy dependence of the cross section sbb and fitting to a line-shape function. • Relativistic Breit-Wigner function. • Radiation correction. • Beam energy spread correction. • The (3S) scan is used to measure energy spread and calibrate energy. • Large sample of data around (4S) peak is used to determine the peak cross-section. Jianchun Wang

  12. BaBar ARGUS CUSB CLEO The (4S) Parameters (For details of BaBar measurement see: B. Aubert, et al., hep-ex/0405025) Jianchun Wang

  13. p+ D B0 D*+ Measurement of B ((4S)B0B0) • Status of R+/0 f+-/f00  B ((4S)B+B-) / B ((4S)B0B0): • Theoretical predications range from 1.03 to 1.25. • Current PDG value (1.0290.0540.045) consistent with unity. • Precise measurement will re-normalize many B decay branching fractions, and contribute to our understanding of isospin violation. • BaBar uses single and double tag events to measure f00. • Only slow p+ (60MeV < P < 200MeV) and (1.5GeV < P < 2.5 GeV) detected. = 1 Jianchun Wang

  14. sideband signal M22 (GeV2) Ms2 (GeV2) Event Samples • PDF of Signal, combinatorial and peaking BB bkg are determined from MC simulation. The continuum bkg are subtracted using continuum data. • Double tag sample contains extra bkg from combinatorial and peaking BB in selecting the first one. These are subtracted using sideband. Jianchun Wang

  15. The Measurement of f00 f00 = 0.486  0.010  0.009 The measurement is independent on B (decay chain), reconstruction efficiency, tB+/tB0, or assumption of isospin symmetry. (ref: B. Aubert, et al., hep-ex/0408022) Jianchun Wang

  16. Summary • CLEO studied Bs in both inclusive and exclusive modes. They found evidence for Bs(*)Bs(*) production at the (5S), dominated by Bs*Bs* mode. • B ((4S)DsX) = (22.30.75.7)% • B (BDsX) = (11.10.42.9)% • B ((5S)DsX) = (55.05.217.8)% • B ((5S)DsX)/B ((4S)DsX) = 2.50.30.6 • B ((5S)Bs(*)Bs(*)) = (2139)%, model dependent • The BaBar had measured (4S) parameters: • M = (10579.30.41.2) MeV, • Gtot = (20.71.62.5) MeV, • Gee = (0.3210.0170.029) keV. • The BaBar measured B ((4S)B0B0)=0.4860.0100.009. Preliminary Jianchun Wang

  17. Backup Slides Jianchun Wang

  18. (5S) (4S) |PDs| / Ebeam |PDs| / Ebeam MC Expectation & Feynman Diagram B Bs Jianchun Wang

  19. Ebeam – Ecandidate (GeV) Mbc (Bs candidate) (GeV) Bs Exclusive Modes Bs decays estimated from B decays. Events 2 4 1 1 Ds(*) decays Jianchun Wang

  20. (4S) Parameter Systematic Errors Jianchun Wang

  21. Systematic Error for f00 f00 = 0.486  0.010  0.009 Jianchun Wang