B Physics perspectives at TeVatron and LHCB

1. B Physics perspectives at TeVatron and LHCB Corfu Summer Institute on Elementary Particle Physics S. Donati, University and INFN Pisa Sep 7, 2005

2. CDF and D0 • Excellent tracker (SVT trigger, M.Dell’Orso, Beauty2005) • Muon coverage up to |h|1.1 • PID (dE/dx + TOF) • Strong tracker (soon SVT like trigger, S. Caron, Beauty2005) • Muon coverage up to |h|2.0 Central Muon Extension (0.6< |h| < 1.0) Central Muon Chambers (|h| < 0.6) Muon Chambers (|h| < 2.0) Integrated luminosity ~1 fb-1 for both experiments

3. Track Triggers and B Physics (CDF) Displaced trk + lepton (e, ) IP(trk) > 120m Pt(lepton) > 4 GeV Semileptonic modes 2-Track Trig. Pt(trk) > 2 GeV IP(trk) > 100 m Fully hadronic modes Di-Muon (J/) Pt() > 1.5 GeV J/ modes down to low Pt(J/)(~ 0 GeV) • -2-body charmless decays (B0,Bs, Lb) • BS mixing • Charm physics • - High statistics lifetime • Tagging, Bs mixing • Masses, lifetimes • (fully rec.BJ/y X) • Quarkonia, rare decays (BS(d) mm ), • Bc (part.rec.BJ/y lX) Secondary Vertex B Decay Length Lxy PT(B)  5 GeV Primary Vertex Lxy  450m Triggering is a very complicated problem, we will come back to it. d = impact parameter

4. Hadronic/semileptonic datasets • Many interesing measurements come from the hadronic/semileptonic datasets. • 2 body hadronic charmless B  hh’ decays (hadronic dataset, CDF-only) • - CP violation in B0 modes, • - BR of Bs modes, • - Angle g, • - Search/Limits B0 and Bs rare decays, • - Search/Limits for Lb hh’ decays and CP violation • - Bs  ff. • Bs mixing (hadronic + semileptonic datasets, CDF+D0).

5. Charmless Bhh’ • Difficult competition with B factories for t-dependent tagged meas. • Interesting B physics measurement of BsBR and ACP(B0Kp) • Signals overlap within mass resolution • Kinematic and dE/dX to disentangle components in a combined fit: M(pp) GeV/c2

6. Separation from Kinematics • Use pp-mass vs signed • momentum imbalance. • a=[1–pmin/pmax] x qmin • discriminates amongst • modes and between • flavors for Kp decays. • All 4 possible mass assignments depend on (a, Mpp) which have all information. M(pp)[GeV/c2] B0d pK (a<0) M2(pK) = M2(B0d) + (2 + a)(m2p- m2K) a B0d pK (a>0) M2(pK) = M2(B0d) + (2 - a)(m2p- m2K)

7. Separation from PID (dE/dx) • K/ separation: 1.4@PT>2 GeV/c • Performance calibrated and separation measured on very pure K and p samples from huge D*+D0+ sample collected by the SVT trigger. Calibration performed in the same momentum range as of the analysis tracks. • Control of systematic errors: Residual gain/baseline fluctuations cause correlated fluctuations of tracks in same event. They have been measured and explicitly included in the fit. dE/dx residuals (ns)

8. Prospects for Bhh’ • Today results on Lint~180 pb-1 (~541 B0Kp) • Very soon(few weeks) new update of the analysis on Lint=360pb-1 (~1600 B0Kp) • The tracking efficiency is increased and we are refining the analysis • We expect a considerable resolution improvement in the new incoming update • To comparate with B-Factories: • BaBar ~1606 B0Kp (227MBBbar) • Belle ~ 3026 B0Kp (386 MBBbar) • We have on tape about 1fb-1 • More than 500 pb-1 were processed and they are ready to be analysed All projections are based on the assumption that in the future we will continue to use the same trigger which we are using TODAY. The trigger is crucial for B-physics.

9. BR(B0pp)/BR(B0 Kp) HFAG 2005 Babar 0.286 ± 0.022 (stat.) Belle 0.238 ± 0.035 (stat.) • Today our measurement on about 121 B0pp • Consistent with B-factories. Valuable cross-check for other measurements. • 360pb-1 we expect (BR( B0 pp)/BR(B0 Kp)) = ±0.026 with about 362 B0pp events 360 pb-1 Lint

10. Direct ACP(B0 Kp) HFAG 2005 Babar -0.133±0.030 (stat.) ± 0.009 (syst.) Belle -0.113 ± 0.022 (stat.) ± 0.008 (syst.) ACP compatible with B-factories, systematic uncertainty comparable as well. With full RunII statistics s(ACP)~1% 360 pb-1 Lint

11. BR(Bs KK) • Perfect U-spin simmetry would predict BR(BsKK)/BR(BdKp)~1, but there is no agreement on the validity of this approximation, and some calculations predict ~2[A. Khodjamirian et al.,Phys.Rev. D68 (2003) 114007]. • Current result favors the second case, but resolution is insufficient • Current resolution BR(BsKK)/BR(BdKp) ~1.7 ± 0.31(stat.)more accurate measurement very desirable • Test with 360 pb-1 will be decisive: expect resolution ±0.14(stat.). 360 pb-1 Lint

12. BsKK vs B0pp Time dependent CP asymmetries Many observables related by U-spin relationship, determine angle g and provide tests for NP using BsKK/B0pp. Time dependent CP asymmetry requires b-flavor tagging. Branching Ratio measurements can constrain theory too… R.Fleisher hep-ph/0405091 Phase space factor = 0.92 QCD sum rules: 1.76+0.15-0.17 (A.Khodyamirian et al., Phys.Rev D68 114007) Branching Ratios

13. R=BR(BsKK)/BR(B0pp) 360 pb-1 R • Determine allowed region in the R vs ACPdir(pp) plan from Babar and Belle measurements • Check theory(or claim New Physics…) by comparing the allowed range with CDF measurement

14. Upper Limits: BR(BsK) Normalized to high statistics mode BR(BdK) Uncertainty on relative isolation efficiency included in limitcalculation Using: BR(BdK ) = 18.2 x 10-6 (HFAG2005) fs = 0.107 and fd = 0.397 (PDG 2004)

15. BR(BsK) expectation • Perturbative QCD approach (Yu, Li, Yu, Phys.Rev. D71 (2005) 074026) • Factorizable + nonfactorizable + annihilation-type diagrams taken into account • Expected BR(BsK π) ~ (6-10)·10-6 • Beneke&Neubert NP B675, 333(2003) • Expected BR(Bs  K π) ~ [7-10] ·10-6 • Suprun-Chicago Flavor Seminar (hep-ph/0307395 & 0404073) • Neglet annihilation-type diagrams • Expected BR(BsK-π+) ~ 4.2·10-6 Yu, Li, Yu, Phys.Rev. D71 (2005) 074026 With 360 pb-1 we expect a sensitivity: BR(BsK) < 5.51 ·10-6 (worst case*) BR(BsK ) < 2.07 ·10-6 (expected*) We are going to test the validity of the theory. Alpha from SM pQCD CDF limit BR(BsKpi)<5.4·10-6 *physics/0308063

16. BR(BsK) and direct ACP Expected a large direct CP asymmetry. As B0K channel the BsK is self-tagging mode and we can measure its ACP Both BR and direct ACP measurement may give a stringent test of validity of theoretical model and overconstrain the CKM parameters Yu, Li, Yu, Phys.Rev. D71 (2005) 074026 360 pb-1 Alpha from SM pQCD Lint

17. BR(Bs) Normalized to BR(BsKK) to avoid uncertainty on (unknown) Bs lifetime Using: -DGs/Gs = 0.12 (Standard Model) -Bs KK = 100% short eigenstate -our measurement of Bs KK/Bd K -BR(Bd K ) = 18.2 x 10-6 (HFAG2005) -fs = 0.107 and fd = 0.397 (PDG 2004) Expected: [0.03 - 0.16] ·10-6 [Beneke&Neuber t NP B675, 333(2003)] Expected: 0.42 ± 0.06 [Li et al. hep-ph/0404028] Great improvement on annihilation mode Bs -+. A factor >100 below PDG04

18. BR(Bd KK) Using: BR(BdK ) = 18.2 x 10-6 (PDG2004) HFAG April 2005: BR(B0KK) < 0.6·10-6 @ 90% C.L. CDF will be close at next round Expected [0.01 - 0.2]·10-6[Beneke&Neubert] NP B675, 333(2003) Both Bs and B0KK are annihilation-dominated decays and no observed yet them – they are hard to predict exactly It will be very interesting to be able to measure one because these unknown amplitudes contribute to many relevant process as BsKK decay

19. Prospects for Lb hh’ • Use the same data to look to search • for charmless Lb decays to ph- • Large direct CP asymmetries expected • Predictions: • BR(LbpK), BR(Lbpp) ~ 10-6 -2*10-6 [Mohanta, Phys. Rev. D63:074001, 2001] • Current limits: • BR(LbpK)<5010-6 @90% C.L. • BR(Lbpp)<5010-6 @90% C.L. • Paper accepted for publication. M(pp)[GeV/c2] Using fL/fd=0.25±0.04: BR(Lbpp)+BR(LbpK)<2310-6 Improved sensitivity in the future with proton PID from TOF+dE/dx With more data, measure BRs and CP violation (expected large)

20. First evidence for BR(Bsff) Normalize to BsJ/yf from hadronic data at 4.8s 12 events 1.95 background M(Bs)[GeV/c2] M(ff)[GeV/c2] Accepted for publication on PRL hep-ex/0502044 BR = (14 +6–5(stat.) ±2(syst.) ±5(BR)) 10-6 (systematics dominated by BR of normalization mode)

21. 12 events 1.95 background estimated yield: 44 events 4.8 s Bs→ff12 events (180 pb-1)44 events (360 pb-1) Plan to perform polarization measurements Towards second generation analyses M(ff)[GeV/c2] M(KKKK)[GeV/c2]

22. Bs Mixing Analysis Strategy • Bs signal reconstruction • Flavour specific states (hadronic & semileptonic channels • Bs decay time • proper time reconstruction • Lifetime measurement • Initial flavour of the Bs • Flavour tagging techniques • calibrate on Bd mixing B0A-scan B0 Mixing perform a “Blind AMPLITUDE SCAN”: A Dmd = 0.5ps-1↔ A =1

23. Bs mixing sensitivity projection (CDF) • New data rolling in, but increasingly peak luminosity: • Keep alive as much as possible present triggers  SVT upgrade • Use new trigger strategies • 2 SVT Tracks + opposite side muon (pt>1.5 GeV) at trigger level • (already in place since summer 2004 can survive at higher luminosity) • Analytic extrapolation, reproduce present result with current inputs • Prediction include a reduced (50%) effective luminosity usable for B-physics from 2007 onwards • Sensitivity to the favorite CKM range • In case of no signal 95% C.L. up to 30 ps-1 with 4 fb-1 • CKM fit will imply New Physics if Dms>28 ps-1 by then…

24. Bs mixing sensitivity projection (D0) With additional channels and improvements in flavor tagging Dms up to 11 ps-1 within reach at 3.5 fb-1

25. Bs mixing sensitivity projection (D0) With increase in bandwidth Dms up to 18 ps-1 Addition of hadronic decay Modes and Layer0 + 50 Hz Bandwidth Dms up to 26 ps-1

26. J/y, leptonic modes and rare B decays Di-Muon Mass (GeV/c2)

27. BsJ/yf and DGs/Gs • BS J/y fm+m- K+K- • BVV decays: Heavy and Light state decay with distinct angular distributions and different lifetimes. • Result (260 pb-1) • 1/4 heavy - 3/4 light state • Lifetime - theavy ~ 2 x tlight • Lifetime difference measures “same” CKM element as Dm (oscillation frequency) • Exciting!! Need more data • Test still possible CP violation effect in Bs mixing

28. Search for Bc at the Tevatron • Bc J/y+l with l=e,m • Not fully reconstructed • Understanding backgrounds • bb events with the J/y • from b and l from b • Fake m or fake e • Other backgrounds • Study J/y+track and Bu J/y K • Look for Bc excess above background and make measurements

29. D0: muon channel analysis Background-only Include Bc contribution Background-only fit is poor compared with addition of signal: D2log(likelihood) is 60 for 5 dof

30. D0: muon channel results Mass log likelihood ct log likelihood NCAND: 95 ±12 ±11 “first 5s Bc result” Mass: 5.95 ±0.34 GeV +0.14 -0.13 ct: 0.448 ±0.121ps +0.123 -0.096 DØ Note: 4539-CONF

31. CDF: Muon channel results Use MC for relative efficiency for Bc and Bu along with Bu->J/yK to obtain: PT(B)>4 and |y| < 1 s(Bc)xB(Bc->J/yln) = s(Bu)xB(Bu ->J/yK) 5.2s Other measurements from this sample are in preparation. CDF Note: 7649

32. CDF: electron channel results • Background • 63.64.9(stat)13.6(syst) • Observed • 178.514.7(stat) • Excess • 114.915.5(stat)13.6(syst) • Significance • 5.9s s(Bc)xB(Bc->J/yln) PT(B)>4 and |y| < 1 = s(Bu)xB(Bu ->J/yK) 0.2820.038(stat.)0.035(yield)0.065(acceptance)

33. Bc summary and perspectives • The study of the Bc is happening in Run II • Semi-leptonic decays observed >5s • D0: J/y m (tri-muon) • CDF: J/y m and J/y e • Small excess in CDF’s J/y p sample • Precision mass compared with theory • Coming soon … • Production spectrum and lifetimes • Stronger fully reconstructed signal

34. B mm in the Standard Model • In Standard Model FCNC decay B  mm heavily suppressed • Standard Model predicts A. Buras Phys. Lett. B 566,115 • Bd mm further suppressed by CKM coupling (Vtd/Vts)2 • Both below sensitivity of Tevatron experiments Observe no events  set limits on new physics Observe events  clear evidence for new physics See also Mario Paolo Giordani’s talk on “BSM Physics at the Tevatron”

35. The Challenge search region • Large combinatorial background • Key elements are • determine efficiencies • select discriminating variables • estimate background

36. Unblinded Results (D0) • Apply optimised cuts • Unblinded results for Bsmm: • Expected background:4.3 1.2 • Observed: 4 BR(Bsmm) < 3.0×10-7 @ 90% CL < 3.7×10-7 @ 95% CL

37. Unblinded Results (CDF) Results with pt(B)>4GeV cut applied No events found in Bs or Bd search windows in either muon pair type

38. now Limits on BR(Bd,smm) (CDF) • BR(Bsmm) < 1.6×10-7 @ 90% CL • < 2.1×10-7 @ 95% CL • BR(Bdmm) < 3.9×10-8 @ 90% CL • < 5.1×10-8 @ 95% CL • These are currently world best limits • The future for CDF: • use optimisation for 1fb-1 • need to reoptimise at 1fb-1 • for best results • assume linear background • scaling

39. b Updated knowledge • Colors: • PDG2004 • CDF contribution beyond current PDG2004 Mass m = 5619.9  1.7 MeV/c2 Lb mass (4.1  2.0) x 10-3 Lc l u (5.5  1.8) % pK + pp < 2.2 x 10-5 Lc+p- p- p+seen Lc(2593) +l u seen Lc(2625)+l u seen Sc++p-l u seen Sc0p+l u seen

40. Triggering at High Luminosity

41. Projected Peak Luminosity Summer 2005, CDF B Triggers out of trigger table if L>10E32 Problem: Trigger Rate(L) = s(L) x L And trigger bandwidth is fixed. Hic sunt leones Bandwidth saturated by current trigger table Sep. 2005, CDF B triggers back up to 1.5x10E32

42. What happens at high luminosity ? (1)

43. What happens at high luminosity ? (2)

44. What happens at high luminosity ? (3)

45. What happens at high luminosity ? (4) The chamber if fully occupied at high luminosity, B triggers depend heavily on online tracking which is problematic at high luminosity. This is a big trouble.

46. Planned improvements: XFT upgrade This plot shows a typical highly non-linear behavior. Confirmation of XFT tracks by stereo layers is expected to yield a substantial reduction of fakes.

47. Peak Luminosity = 3E32 34% 66% Inst. Luminosity (E32) hours Typical Projected Store Evolution - The store time evolution could be such that, even if is nothing is done, B triggers are alive for a significant amount of time. - Lint rescaled to 0.66 x Lint.

48. Tevatron B physics prospects Many interesting B Physics measurements would be possible with 8 fb-1. We were promised L=1E32 and Tib=132 ns We will get L=3E32 and Tib=396 ns This gives us an headache, CDF & D0 triggers were not designed for L>1E32. We can use these collisions if we can trigger on them, CDF B triggers were dead beyond 1E32 up to Aug 2005, now they will survive up to 1.5E32. They will be dead again beyond 1.5E32 unless we do something really smart. XFT upgrade, SVT upgrade crucial in triggering beyond 1.5E32 at CDF.

49. LHCb

50. Introduction • LHCb is a dedicated experiment to study CP violation and other rare • phenomena in B meson decays (and also c,τ,jets,…): - Precision measurement of CKM parameters; - Test of Standard Model predictions / search for new physics - Expect ~1012 b-hadrons / year • All b-species are produced: Bu (~40%), Bd (~40%), Bs (~10%), Bc (~0.1%), Λb (~10%), … , Excited states, … • Bu, Bd are being explored in great detail (thanks to B-factories) => Improve statistics (other sources of systematics) • Bs time resolved studies (not accessible at B-factories)