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A. Drutskoy University of Cincinnati

A. Drutskoy University of Cincinnati. B s physics at Y(5S) in Belle experiment. SLAC Experimental Seminar. January 17, 2006, SLAC. Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy. Outline. Introduction. Data taking. Number of bb events at Y(5S) dataset.

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A. Drutskoy University of Cincinnati

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  1. A. Drutskoy University of Cincinnati Bs physics at Y(5S) in Belle experiment SLAC Experimental Seminar January 17, 2006, SLAC. Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  2. Outline Introduction. Data taking. Number of bb events at Y(5S) dataset. Inclusive production of J/Y, D0 and Ds at Y(5S). Exclusive decays Bs-> J/Yf(/h) and Bs-> Ds+(*)p-(/r-). Search for rare Bs decays. Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  3. CLEO PRL 54, 381 (1985) (5S) Introduction Asymmetric energy e+e- colliders (B Factories) running at Y(4S) : Belle and BaBar 1985: CESR (CLEO,CUSB) ~116 pb-1 at Y(5S) 2003: CESR (CLEO III) ~0.42 fb-1 at Y(5S) _ e+ e- ->Y(4S) -> BB, where B is B+ or B0 meson _ _ _ _ _ _ _ _ e+ e- -> Y(5S) -> BB,B*B, B*B*, BBp, BBpp, BsBs, Bs*Bs, Bs*Bs* where B* -> B gandBs* -> Bsg _ _ _ B0 = s b , B0 = s b s s Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  4. Masses, widths, lifetimes, CM momenta Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  5. Electron and positron beam energies have to be increased by 2.7% (same Lorentz boost bg = 0.425) to move from Y(4S) to Y(5S). No modifications are required for Belle detector, trigger system or software to move from Y(4S) to Y(5S). Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  6. Engineering run at Y(5S) 3 days of engineering run at Y(5S) : June 21 – June 23. Plan for 3 day engineering runs: 1. Energy scan: five points with ~30 pb-1 at each point: 10825, 10845, 10865, 10885 and 10905 MeV. 2. Data taking at Y(5S) peak; to collect integral lumi ~2 fb-1 . Results: Y(5S) peak position ECM=10869 MeV was chosen from energy scan. Integrated luminosity of ~1.86 fb-1 (ECL lumi) was taken !!! Maximum luminosity ~13.9 /nb/sec, almost 100% of Y(4S) specific luminosity (taking into account smaller currents). Belle can take 1 fb-1 per day at Y(5S) or even more. Very smooth running, all goals are reached. Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  7. Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  8. CLEO PRL 54, 381 (1985) (5S) Hadronic event classification hadronic events at U(5S) U(5S) events u,d,s,c continuum b continuum bb events B0, B+ events Bs events Bs* Bs* channel Bs* Bs Bs Bs Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  9. Number of Bs in dataset To calculate any exclusive branching fraction we must know the full number of Bs* Bs* events. To calculate any inclusive branching fraction we must know the full number of Bs mesons. To obtain the full number of initial Bs* Bs* events in our data sample we should go through steps: 1. Obtain the number of hadronic events in Y(5S) dataset. 2.Subtract u,d,s,c continuum using continuum data below Y(4S) with luminosity scale factor. 3. Calculate the ratioN(Bs(*)Bs(*)) / N(bb) using inclusive Ds and D0 spectra. 4. Calculate the ratioN(Bs*Bs*)/ N(Bs(*)Bs(*)) using reconstructed exclusive events. Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  10. Number of bb events. Ncont(5S) = Ncont(E=10.519)* L(5S) / L(cont) * (Econt/E5S)2 (e5S/ econt) Y(5S) : Lumi = 1.857 ± 0.001 (stat) fb-1 Cont : Lumi = 3.670 ± 0.001 (stat) fb-1 2 s ~ 1/Ecm (1.857/3.67)*(10.5189/10.869)2 = 0.4740± 0.0019 e5S/ econt= 1.007 ± 0.003 Nbb(5S) = 561,000 ± 3,000 ±29,000 R = s(hadrons) / s(mm) Nbb(5S) / fb-1 = 302,000 ±15,000 CLEO : 0.42 fb-1 Nbb(5S)/ fb-1 = 310,000 ± 52,000 Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  11. Luminosity ratio L (5S) / L (continuum). L (5S) / L (cont) = 0.4740 ± 0.0019 We obtained luminosity ratio: Luminosity ratio can be checked using the ratio of normalized momentum distributions of fastest charged track, fastest K0 and D0 mesons. Using MC simulation CLEO obtained (0.6 ± 1.1)% correction for new channels opening. That correction was applied to these numbers. 0.471 ± 0.005 0.477 ± 0.005 0.471 ± 0.005 => Good agreement within errors with energy corrected luminosity ratio. Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  12. Inclusive analyses : selections Particle ID: p/K : standard ID(K/p) J/Y -> m+m- : Standard Muon ID D0 -> K+p- : no cuts Ds -> fp: | M(f) –M(K+K-) | < 12 MeV/c2~3s |cos(qheli) (Ds)| > 0.25 for fp+ No continuum suppression cuts. Ratio of Bs(*) Bs(*) pair number to all bb pair number fs =N(Bs(*) Bs(*)) / N(bb)can be obtained from: Bf (Y(5S) -> Ds X) / 2 = fsBf (Bs -> Ds X) + (1- fs) Bf (B -> Ds X) x x Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  13. Inclusive analysis : Y(5S) -> Ds X Theory : hep- ex/0508047 CLEO Y(5S) P/Pmax< 1 Bf (Bs -> DsX) = (92 ± 11) % PDG : Bf (Ds-> fp+)=(3.6 ± 0.9)% Babar : Bf(Ds-> fp+)=(4.8 ± 0.6)% Ds-> fp+ Sum: Bf(Ds-> fp+) = (4.4 ± 0.5)% 3775 ± 100 ev CLEO : Bf (B -> DsX) = ( 9.0 ± 0.3 ±1.4)% Babar : Bf (B -> DsX) = ( 8.94 ± 0.16 ± 1.12)% After continuum subtraction and efficiency correction: Bf (Y(5S) -> Ds X) 2 = (22.6 ± 1.2 ± 2.8) % CLEO measured: Bf (Y(5S) -> Ds X) / 2 = (22.35 ± 2.1 ± 4.95)% => fs = (16.4 ± 1.4 ± 4.1 )% Syst. err. dominates by Bf(Ds->fp+) Using Ds mesons CLEO measured fs = (16.0 ± 2.6 ± 5.8 )% Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  14. Inclusive analysis : Y(5S) -> D0 X Theory : hep- ex/0508047 CLEO Y(5S) Bf (Bs -> D0X) = (8 ± 7) % PDG: D0 -> K-p+ Bf (B -> D0X) = (63.7 ± 3.0) % 55009 ± 510 ev Bf (D0 -> K-p+) = (3.81 ± 0.09 ) % P/Pmax< 1 After continuum subtraction and efficiency correction: Bf (Y(5S) -> D0 X) 2 = (53.3 ± 2.0 ± 2.9) % Then we obtain ratio fs =N(Bs(*) Bs(*)) / N(bb) : fs = (18.7 ± 3.6 ± 6.7 )% Syst. error dominates by N(bb). Using Ds mesons CLEO measured fs = (16.0 ± 2.6 ± 5.8 )% Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  15. Inclusive analysis : Y(5S) -> J/Y X Theory : Bf(Bs-> J/Y X) P/Pmax<0.5 Y(5S) = 1.00 ± 0.10 Bf(B-> J/Y X) 446±28 ev m+m- PDG: Bf (B -> J/Y X) = (1.094 ± 0.032) % Bf (J/Y -> m+m- ) = (5.88 ± 0.10 ) % After continuum subtraction and efficiency correction: Bf (Y(5S) -> J/Y X) 2 = (1.068 ± 0.086 ± 0.057) % Good agreement with expectations => bb number is correct Assuming approximately 17% Bs(*)Bs(*) production over bb : Bf ( Bs -> J/Y X) = ( 0.94 ± 0.51 ± 0.37 ) % Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  16. Exclusive analysis: signature of fully reconstructed Bs decays BsBs , Bs*Bs, Bs*Bs* Mbc vs DE Mbc = E*beam2 – P*B2 e+ e- -> Y(5S) -> BB, B*B,B*B*,BsBs,Bs*Bs, Bs*Bs* where B* -> B gand Bs* -> Bsg Detailed MC event simulation and reconstruction with Belle detector was performed. Figures are shown for decay mode Bs -> Ds-p+ with Ds- -> fp- . Bs signal can be well separated for BsBs, Bs*Bs and Bs* Bs* final states. Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  17. Exclusive analyses: selections Particle ID: K/p: standard ID(K/p) ; standard lepton ID Masses: p0–>gg3s KS –> p+p-3s K*0 –> K+p- h–> gg 2.5s r+ –> p+p0 , P(g) >150 MeV/c f– > K+K-3s –30 < M(m+m-) –M(J/y) < 30 MeV/c2 3s –100 < M(e+e-) –M(J/y) < 30 MeV/c2 Ds+ -> fp+ , K*0 K+, Ks K+3s Ds*+ -> Ds+g : M(Dsg)- M(D*s),2s , P(g)>50 MeV/c Continuum suppression: Angle between Bs thrusts: |cosq| < 0.8for Ds(*)+p- ; |cosq| < 0.9 for J/Y ; |cosq| < 0.7for Ds(*)+r- ; |cosq| < 0.6 for K*0 K+ modes ; Fox2<0.3 for Ds(*)+p-/ r-; Fox2<0.4 for J/y modes Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  18. Exclusive Bs -> Ds(*)+p- decays Bs -> Ds+p- Bs -> Ds*+p- BsBs , Bs*Bs, Bs*Bs* MC 9 events in Bs* Bs* 4 events in Bs* Bs* Ds+ -> f p+ , Ds+ -> K*0 K+,Ds+ -> Ks K+ Clear signal at Bs* Bs* channel ; no signals in Bs* Bs and BsBs channels. Taking full number of Bs from inclusive analysis: Bf(Bs -> Ds+p- ) = (0.65 ± 0.21 ± 0.19)% CDF measured Bf ratio, taking Bf(B0->D+p-) from PDG: (0.40 ± 0.06 ± 0.13)% Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  19. Exclusive Bs -> Ds(*)+r- and Bs -> J/y f/h decays Bs -> Ds(*)+r- Bs -> J/y f/h 7 events in Bs* Bs* 3 events in Bs* Bs* Bs -> J/y f, Bs -> J/y h(gg) Ds+->f p+ ,Ds+->K*0 K+,Ds+->KsK+ Clear signal at Bs* Bs* channel ; signals in Bs* Bs and BsBs channels are not seen. Bs* Bs* channel dominance was also observed by CLEO (next slide). We can combine all shown channels to obtain quantitative Bs(*) parameters. Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  20. BsJ/' , J/+e+e-  K+K BsDs(*) Ds*Ds DsK+K0 K+K*0 Preliminary Ebeam – Ecandidate (GeV) Ebeam – Ecandidate (GeV) Mbc (Bs candidate) (GeV) Mbc (Bs candidate) (GeV) Exclusive Bs Signals at the (5S) Nsignal = 4, Nbkg  0.1 Nsignal = 8, Nbkg  1 (5S) decay to Bs(*)Bs(*) is dominated by the Bs*Bs* mode! H. Vogel, CLEO, FPCP 2004 (obsolete), Korea, exclusive Bs decays - 13 - Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  21. DE distributions, sum of all Bs decay modes 5.408< MBC<5.429 GeV/c2 5.384< MBC<5.405GeV/c2 5.36< MBC<5.38GeV/c2 Bs* Bs* Bs* Bs Bs Bs Nev=20.0 ± 4.8 6.7 s Small signal, Nev= 1.3 ± 2.0 (6± 96)% Decay U(5S) -> Bs* Bs* , with Bs* -> Bsg. Potential models predict Bs* Bs* dominance over Bs*Bs and BsBs channels, but not so strong. DE peak = Ecm(accel.)/2 – Ecm(real)/2 – E(g) DE peak = – 47.6 ± 2.6 MeV Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  22. MBC distribution, sum of all Bs decay modes - 0.08<DE<- 0.02 MeV - 0.08<DE<- 0.02 MeV Bs* Bs* Bs* Bs* Mbc = (E*B+DEpeak)2 – P*B2 Mbc = E*B2 – P*B2 M (Bs) = 5370 ± 1 ± 3 MeV/c2 Ecm = 10869 MeV ; E*B = Ecm/2 PDG: M (Bs) = 5369.6 ± 2.4 MeV/c2 M (Bs*) = 5418 ± 1 ±(acc. err) MeV/c2 CDF: M (Bs) = 5366.0 ± 0.8 MeV/c2 Photon momentum is neglected => does not change Bs* mass position, only smearing. Photon energy smearing does not change Bs mass position Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  23. Number of Bs in dataset Lumi = 1.857 fb-1 hadronic events at Y(5S) bb continuum included bb events N ev =561,000 ± 3,000 ±29,000 fs = (16.4 ± 1.4 ± 4.1 )% Bs events N ev =92,000 ± 8,000 ±23,000 f(Bs*Bs*) = (94 ± 69)% Bs* Bs* channel N ev =86,500 ± 7,500 ±22,500 Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  24. Exclusive Bs -> K+ K- and Bs -> f g decays Bs -> f g Bs -> K+ K- MC Fox2 < 0.3, Fox2 < 0.4, |cos q| < 0.5 |cos q| < 0.8 K- : tight ID(K/p), Bgr. ~ 0.15 ev. Est. sign.~ 0.4 ev. Bgr. ~ 0.14 ev. Est. sign.~ 0.7 ev. Partner of B -> K* g penguin decay Partner of B -> K+ p- penguin decay Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  25. CDF: Bs-> h+ h’- decays Unbinned likelihood fit. fs Bf( Bs -> K+ K-) = 0.50 ± 0.08 ± 0.07 fd Bf( B0 -> K+ p-) fs Bf( Bs -> K+ p-) < 0.11 (90%CL) fd Bf( B0 -> K+ p-) Bf( Bs -> p+ p-) < 0.10 (90%CL) Bf( Bs -> K+ K-) No absolute branching fractions. Statistical separation of final states. Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  26. Exclusive Bs -> Ds(*)+ Ds(*)-decays Bs-> Ds+ Ds- Bf(Bs->Ds+ Ds-) < 7.1% at 90% CL Bs-> Ds*+ Ds- Bf(Bs->Ds*+ Ds-) < 12.7% at 90% CL Bs-> Ds+ Ds*- Bf(Bs->Ds*+ Ds*-) < 27.3% at 90% CL Bs-> Ds*+ Ds*- Expected (2 fb-1): ~ 0.5 events in each mode. Bf (Bs->Ds(*)+Ds(*)-) = (12 ± 5 )% Expected with 30 fb-1: Ds+ -> fp+ , K*0 K+, Ks K+ Fox2 < 0.4 Bs->Ds(*) +Ds(*) - decays are CP- even states with large BF’s, leading to large DGs/Gs: |cos q| < 0.8 Angle between B thrusts: DGs Bf(Bs->Ds(*) + Ds(*) - ) should be compared with direct measurement to test SM. ~ <= ~ Gs 1- Bf(Bs->Ds(*) + Ds(*) - ) / 2 Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  27. Exclusive Bs -> g gdecay Bs -> g g MC DE Natural mode to search for BSM effects, many theoretical papers devoted to this decay. In SM: Bf(Bs-> gg ) = (0.5-1.0) x 10-6 BSM can increase Bf up to two orders MC Fox2 < 0.5 |cos q| < 0.8 90% CL UL with 1.86 fb-1 : Bf(Bs -> gg ) < 0.56 x 10- 4. Better than PDG limit : < 1.48 x 10-4 Many “conventional” BSM models can be better constrained by B -> K* g and B->s g g processes, however not all. In some BSM models Bs ->gg provides the best limit, in particular in 4-generation model (VTs) and R- parity violation SUSY ( x M(gg)). Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  28. Signals with 50 fb-1 Bs -> Ds(*)+ Ds(*)- - CP eigenstate Bs -> g g - intrinsic penguin Bs -> K+ K- - penguin Bs -> f g - radiative penguin Bs -> DsJp - tree with DsJ Bs -> Ds+ K- - Cabibbo suppressed Bs -> Ds+l- n - exclusive leptonic Bs -> D0 KS0 - color suppressed Bs lifetime Bs semileptonic It seems, very strong physics program can be performed with 50 fb-1: Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  29. Conclusions Inclusive production branching fractions of J/Y, D0 and Ds mesons are measured at Y(5S). Ratio of Bs meson production over all bb-events is measured:fs = (16.4 ± 1.4 ± 4.1 )% Significant exclusive Bs signals are observed in Y(5S) ->Bs* Bs* channel. Combining all studied decay modes, mass of Bs* meson was measured: M(Bs*) = 5418 ± 1 ± (acc. err) MeV/c2, and mass of Bs was measured: M (Bs) = 5370 ± 1 ± 3 MeV/c2. Obtained Bs mass is in agreement with recent CDF measurement M (Bs) = 5366.0 ± 0.8 MeV/c2. Good agreement with published CLEO results is obtained in both inclusive and exclusive analyses. Our Y(5S) dataset is 4.4 times larger than CLEO dataset, providing better accuracy. Rare Bs decays are searched for at Y(5S) for the first time. Many new interesting results can be obtained with 50 fb-1. Significant signals are expected in many Bs decays with 50 fb-1 (maybe 30 fb-1) Engineering runs demonstrated, that background level is not large for studied decay modes. Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  30. Background slides Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

  31. CDF: Bs-> Ds-p+ decays Results with 119 pb-1 : fs Bf( Bs -> Ds-p+) = 0.35 ± 0.05 ± 0.04 ± 0.09 fd Bf( B0 -> D-p+) From PDG : fs / fd = 0.270±0.028 , fs is rate of “b quark” -> Bs Uncertainty of absolute branching fraction measurement dominates already by 10% uncertainty of fs/fd. Bf( Bs -> Ds-p+) = 1.4 ± 0.2(stat) ± 0.2(syst) ± 0.4(BF) ± 0.2(PR) Bf( B0 -> D-p+) Bs physics at Y(5S), SLAC seminar, Jan 17, 2006, A. Drutskoy

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