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A. Drutskoy University of Cincinnati

A. Drutskoy University of Cincinnati. Results from the Y(5S) Engineering Run at Belle. Joint Experimental-Theoretical Seminar. July 7, 2006, Fermilab. Fermilab seminar Results from the U (5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy. Outline.

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A. Drutskoy University of Cincinnati

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  1. A. Drutskoy University of Cincinnati Results from the Y(5S) Engineering Run at Belle Joint Experimental-Theoretical Seminar July 7, 2006, Fermilab. Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  2. Outline Introduction. Data taking. Number of bb events at Y(5S) dataset. Inclusive production of Ds, D0 and J/Y at Y(5S). Exclusive decays Bs-> J/Yf(/h) and Bs-> Ds+(*)p-(/r-). Search for rare Bs decays. Results are based on 1.86 fb-1 dataset taken at Y(5S). All results in this talk areBelle preliminary. Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  3. CLEO PRL 54, 381 (1985) CLEO PRL 54, 381 (1985) (5S) (5S) Introduction (4S) 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) 2005: Belle, KEKB ~ 1.86 fb-1 at Y(5S) 2006, June 9-31: Belle, KEKB ~21.7 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 Bs rate is ~10-20% => high lumi e+e- collider at the Y(5S) -> Bs factory. Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  4. Masses, widths, lifetimes, CM momenta Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  5. Y(5S) Engineering Run at the KEKB e+e- collider Belle Electron and positron beam energies were increased by 2.7% (same Lorentz boost bg = 0.425) to move from Y(4S) to Y(5S). 8 GeVe- 3.5 GeV e+ Beam currents were lowered by ~10% to keep background level under control. 2005: Energy scan (30pb-1 at 5 points) : Y(5S) peak position ECM = 10869 MeV chosen. 3 days of engineering run at Y(5S) : June 21 – June 23 , 2005 => 1.86 fb-1 ; Very smooth running ! Almost 100% of Y(4S) specific luminosity. Belle can take > 1 fb-1 per day at Y(5S). Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  6. Energy scan Non-relativistic Breit-Wigner to describe signal and Const to describe background. Shape is slightly asymmetric(?). Energy scan was performed to find the best position for following Y(5S) runs. Not enough energy range to measure Y(5S) mass and width. Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  7. No modifications are required for Belle detector, trigger system or software to move from Y(4S) to Y(5S). Beam currents were lowered : backgrounds are similar to Y(4S) runs Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  8. Y(5S) Engineering Run Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  9. New 2006 run at Y(5S) at Belle Belle collected more data at Y(5S): June 9 - June 31, 2006 =>21.7 fb-1 Exceeded 1.2fb-1/day for the first time (4S). Daily luminosity Correction factor(1.056) is necessary for 5S run due to smaller Bhabha Cross section. 5S run ~22 fb-1 Off-resonance run Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  10. New 2006 run at Y(5S) at Belle Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  11. Belle integrated luminosity at Y(4S) • Integrated luminosity reached 600 fb-1 on May-31st . ~630fb-1 Belle May-31st Babar Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  12. Move to Test Stand for Cool-down & High Power Test Crab cavity for HER Mt. Tsukuba Luminosity will be increased ~ twice after crab cavity installation. Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  13. CLEO PRL 54, 381 (1985) (5S) Hadronic event classification hadronic events at U(5S) u,d,s,c continuum U(5S) events b continuum N(bb events) = N(hadr, 5S) - N(udsc, 5S) bb events B0, B+ events Bs events fs = N(Bs(*) Bs(*)) / N(bb) Bs* Bs* channel Bs* Bs Bs Bs Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  14. Number of bb events, number of Bs events - - - - Continuum event yield (uu,dd,ss,cc) is estimated using data taken below the Y(4S): 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 (below 4S) : 3.670 ± 0.001 (stat) fb-1 Nbb(5S) = 561,000 ± 3,000 ±29,000 events => 5% uncertainty from luminosity ratio CLEO: Nbb(5S)/ fb-1 = 310,000 ± 52,000 Nbb(5S) / fb-1 = 302,000 ±15,000 How to determine fs =N(Bs(*) Bs(*)) / N(bb)? bb at Y(5S) _ _ Bs Bs B B Bf (Y(5S) -> Ds X) / 2 = fsBf (Bs -> Ds X) + (1-fs) Bf (B -> Ds X) x x 1. Bf (Bs -> Ds X) can be predicted theoretically, tree diagrams, large. 2. Bf (B -> Ds X) is well measured at the Y(4S). Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  15. Luminosity ratio L (5S) / L (continuum). L (5S) / L (cont) = 0.4740 ± 0.0019 We obtained energy corrected luminosity ratio: Luminosity ratio can be checked using the ratio of normalized momentum distributions of fastest charged track, fastest K0 and D0 mesons. 0.471 ± 0.005 0.477 ± 0.005 0.471 ± 0.005 => Good agreement within errors with energy corrected luminosity ratio. Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  16. 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. Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  17. Inclusive analysis : Y(5S) -> Ds X , Ds -> f p Theory : points:5S hist: cont hep- ex/0508047 CLEO Y(5S) P/Pmax< 1 Bf (Bs -> DsX) = (92 ± 11) % PDG 2006: Ds-> fp+ Bf (B -> DsX) = ( 8.6 ± 1.2)% 3775 ± 100 ev Bf(Ds-> fp+) = (4.4 ± 0.6)% After continuum subtraction and efficiency correction: Bf (Y(5S) -> Ds X) 2 = (23.6 ± 1.2 ± 3.6) % => fs = (17.9 ± 1.4 ± 4.1 )% Syst. err. dominates by Bf(Ds->fp+) Similarly, CLEO measured fs = (16.0 ± 2.6 ± 5.8 )% Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  18. Inclusive analysis : Y(5S) -> D0 X , D0 -> K-p+ points:5S hist: cont Theory : hep- ex/0508047 CLEO Y(5S) Bf (Bs -> D0X) = (8 ± 7) % PDG 2006: D0 -> K-p+ Bf (B -> D0X) = (64.0 ± 3.0) % 55009 ± 510 ev P/Pmax< 1 Bf (D0 -> K-p+) = (3.80 ± 0.07) % After continuum subtraction and efficiency correction: Bf (Y(5S) -> D0 X) 2 = (53.8 ± 2.0 ± 3.4) % => fs = (18.1 ± 3.6 ± 7.5 )% Syst. error dominated by N(bb). Combining with Ds result: fs = (18.0 ± 1.3 ± 3.2 )% CLEO measurement: fs = (16.0 ± 2.6 ± 5.8 )% Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  19. Inclusive analysis : Y(5S)-> J/Y X , J/Y -> m+m- Theory : points:5S hist: cont 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 = (1.030 ± 0.080 ± 0.067) % Good agreement with expectations => bb number is correct Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  20. Signature of fully reconstructed exclusive Bs decays BsBs , Bs*Bs, Bs*Bs* MC MC Mbc vs DE whereBs* -> Bsg e+ e- -> Y(5S) -> BsBs, Bs*Bs,Bs*Bs*, Reconstruction: Bsenergy and momentum, photonfrom Bs* is not reconstructed. Mbc = E*beam2 – P*B2 , DE = E*B – E*beam Two variables calculated: Detailed MC event simulation and reconstruction with Belle detector was performed. Figures are shown for the decay mode Bs -> Ds-p+ with Ds- -> fp- . The signals for BsBs, Bs*Bs and Bs* Bs* can be well separated. Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  21. 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 Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  22. Exclusive Bs -> Ds(*)+p- decays Bs -> Ds+p- BsBs , Bs*Bs, Bs*Bs* Bs -> Ds*+p- 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. Taking # of Bs’s from the 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)% Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  23. 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* dominance was also observed by CLEO. We can combine all shown channels to obtain quantitative Bs(*) parameters. Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  24. 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) CLEO: 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 Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  25. 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 Nev= 1.3 ± 2.0 ev. => small signal N(Bs*Bs*) / N(Bs(*)Bs(*))= (94± 69)% 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 Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  26. 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 = M(Bs) Mbc = E*B2 – P*B2 = M(Bs*) 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±3 (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 Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  27. 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 )% fs = (18.0 ± 1.3 ± 3.2 )% Bs events N ev =101,000 ± 7,000 ±19,000 f(Bs*Bs*) = (94 ± 69)% Bs* Bs* channel N ev =95,000 ± 7,000 ±20,000 ~105 Bs mesons per 1 fb-1 at Y(5S) Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  28. Exclusive Bs -> K+ K- and Bs -> f g decays Bs -> f g Bs -> K+ K- MC Tight cuts are used to suppress backgr. Signal: 1 event Bgr. ~ 0.15 ev. Est. sign.~ 0.4 ev. Signal: 2 events Bgr. ~ 0.14 ev. Est. sign.~ 0.7 ev. Partner of B -> K* g penguin decay Partner of B -> K+ p- penguin decay Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  29. 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(*)-) = (14 ± 5 )% Expected with 23 fb-1: Ds+ -> fp+ , K*0 K+, Ks K+ Bs->Ds(*) +Ds(*) - decays are CP- even states with large BF’s, leading to large DGs/Gs: DGs Bf(Bs->Ds(*) + Ds(*) - ) should be compared with direct DGs/Gs measurement to test SM. ~ <= ~ Gs 1- Bf(Bs->Ds(*) + Ds(*) - ) / 2 Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  30. 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 90% CL UL with 1.86 fb-1 :Bf (Bs -> gg ) < 0.56 x 10- 4. PDG limit : Bf (Bs -> gg ) < 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 violating SUSY ( x M(gg)). Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  31. Tasks expected with 23 fb-1 Bs -> Ds(*)+p (/r)- - direct measurements with stat. error ~15% Bs -> J/Yh (h’/f) - CP eigenstate Bs -> Ds(*)+ Ds(*)- - CP eigenstate, DGs / Gs estimate Bs -> g g - the best world upper limit (intrinsic penguin) Bs -> K+ K- - penguin, to compare with B->Kp Bs -> f g - radiative penguin , to compare with B->K*g Bs -> DsJp - tree with DsJ , to test DsJ production mechanism Bs -> Ds+l- n - exclusive leptonic, SU(3) test Bs -> D0 KS0 - color suppressed, no rescattering diagram Bs lifetime - precision ~ 5% using same sign leptons Bs semileptonic - accuracy ~ 5-10%, quark-hadron duality test It seems, very strong physics program can be performed with 23 fb-1: Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  32. Feasibility of Bs lifetime measurement with same sign leptons Lifetime can be measured using two fast same sign lepton tracks and beam profile. To remove secondary D meson semileptonic decays: P(l)>1.4 GeV. Y(5S) : Bs(l +) Bs(l +) / Bs(l +) Bs(l -) = 100% Y(5S) : B(l +) B(l +) / B(l +) B(l -) ~ 10% m+ m+ Beam profile Dz = bgc Dt Bs Y(5S) Bs Z beam ~ 3 mm; Dz ~ 0.1- 0.2 mm. Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  33. Comparison with Fermilab Bs studies. There are several topics, where Y(5) running has advantages comparing with CDF and D0: 1) Model independent branching fraction measurements. 2) Measurement of decay modes with g, p0 and h in final state (Ds+r-). 3) Measurement of multiparticle final states (like Ds+ Ds-). 4) Inclusive branching fraction measurements (semileptonic Bs). 5) Partial reconstruction (Bf (Ds+ l-n) using “missing- mass” method). There are also disadvantages: 1) We have to choose between running at Y(4S) or Y(5S). 2) Number of Bs is smaller than in Fermilab experiments. 3) Vertex resolution is not good enough to measure Bs mixing. Running at Y(5S) is a new tool to study Bs physics. First Belle results are very promising. Collider exists => relatively low price. Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  34. 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 determined:fs = (16.4 ± 1.4 ± 4.1 )% (in good agreement with CLEO). 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. Rare Bs decays are searched for at Y(5S) for the first time. Bs studiesat e+ e- colliders running atY(5S) have many advantages comparing with hadron-hadron colliders: high efficiency of photon reconstruction; no problems with trigger efficiency; good K/p PID. Many new interesting results can be obtained with 23 fb-1. Significant signals are expected in many Bs decays with 23 fb-1. Engineering runs demonstrated, that background level is not large for studied decays. Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  35. Background slides Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  36. 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+) Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

  37. 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. Fermilab seminar Results from the U(5S) Engineering Run at Belle , July 7, 2006 A. Drutskoy

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