1 / 26

Tevatron results B. Casey, FNAL

Katie: 3.5. Tevatron results B. Casey, FNAL. Pono: 6.1. Outline. Overall comparison on Tevatron and 4S/5S environments Cover selected B s physics results from D Ø and CDF Try and point out where measurements can be improved with 5S data (or complement 4S data) Topics: B s lifetime

nitesh
Download Presentation

Tevatron results B. Casey, FNAL

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Katie: 3.5 Tevatron resultsB. Casey, FNAL Pono: 6.1

  2. Outline • Overall comparison on Tevatron and 4S/5S environments • Cover selected Bs physics results from DØ and CDF • Try and point out where measurements can be improved with 5S data (or complement 4S data) • Topics: • Bs lifetime • DG/fs • Rare decays B. Casey, BNM 2008

  3. Tevatron versus Belle If you can do it, you can do it better at Belle Still many interesting things you can only do now at the Tevatron B. Casey, BNM 2008

  4. Tevatron versus Belle B-factory numbers approximated for 250 fb-1, Tevatron numbers estimated at 1 fb-1 Dimuons about same Tev on top for now Vertex versus muon trigger h+h- ~same but no p0s Tev on top for now Some things only at 5S B. Casey, BNM 2008

  5. Lifetime Ratios Sensitive probe of higher order terms in HQE 1: Franco et al hep-ph/0203089 2: PDG07 + new DØ 3: HFAG07 (not recent CDF) Statistics or something else? B. Casey, BNM 2008

  6. Bs Lifetime Complicated by sizeable DG = GH-GL Flavor specific 1-D lifetime fit to Dsln, Dsp… Direct Simultaneous fit to lifetime and polarization in J/yf Bd 40% reduction in error including FS But also drives discrepancy with Bd B. Casey, BNM 2008

  7. Semileptonic Bs lifetime Apply boost correction determined from MC Reconstruct signal as Ds correlated with muon Fit for lifetime ~90% signal, ~10% peaking backgrounds: B→DsD, direct DsD B. Casey, BNM 2008

  8. Hadronic Bs lifetime Correct for trigger efficiency Fully reconstruct Bs signal and boost No background or boost issues, but need precise trigger model Fit for lifetime B. Casey, BNM 2008

  9. Lifetime results Cross checks with Bd lifetime in the same topologies: DØ/world = 1.01 ± 0.06 CDF/world = 0.99 ± 0.02 World average ~2.5 s below Bd lifetime B. Casey, BNM 2008

  10. Bs lifetime at the 5S • Less uncertainty associated with high statistics semileptonic modes • known boost • background samples from 4S • Tevatron: • Hadronic results still stat limited • semileptonic can move to direct lifetime ratio measurement to reduce sys. • Both cases: Not far from sys. limited • If there is a Bs lifetime problem, it needs to be confirmed in a b-factory environment • we will always want a good Bs lifetime measurement independent of J/yf B. Casey, BNM 2008

  11. Bs mixing parameters Dm lifetime/ flight length 1/GH Log(dN/dt) DG 1/GL f lifetime/ flight length B. Casey, BNM 2008

  12. DG and CPV in the Bs system • all measurements are untagged (or time-integrated) • Sensitivity to CPV in untagged samples if DG≠ 0 • Everything is DG x f(fs) • Theory prediction for DG very important • Cant be trusted without t (Bs) /t (Bd) • Ds(*)Ds(*) theory errors uncontrolled • Best DG measurement but not used in constraint B. Casey, BNM 2008

  13. DG and D(*)s D(*)s Measured through correlated production of Ds→fp and Ds→fmn Or fully reconstructed channels f Ds Partial reconstruction more complicated but gives direct access to DGCP B. Casey, BNM 2008

  14. DG and Ds K Recently proposedby to use lifetime measurement in DsK to determine sign of strong phases for J/yf and remove 2-fold ambiguity (Nandi, Nierste hep-arXiv:0801.0143) PID variable based on dE/dx and momentum asymmetry 109±19 DsK events ~8 s significance B. Casey, BNM 2008

  15. DG and Untagged J/yf Lifetime tells you if you are looking at a B long or a B short Polarization tells if you are looking at an even or odd Bs even light odd heavy Comparing the two (plus interference terms) allows CPV measurement B. Casey, BNM 2008

  16. Tagged versus untagged Adding tagging where available increases sensitivity (but eD2 ~ 5%) tagged untagged Points are 95% CL from untagged (I added) More importantly, extra terms partially reduce 4 fold ambiguity to 2 fold ambiguity B. Casey, BNM 2008

  17. DG/fs at the 5S • Tevatron: 10 publications on DG and fs so far, only 1 includes time dependent tagging • Combined DØ/CDF: tagged/untagged J/yf, AS,, tFS will be interesting • If fs is large: • Decreasing ambiguities more important than tagging • BF(Ds(*)Ds(*)), t(DsK) • If fs is large: • Tevatron + Belle can discover new physics before LHC • At least we need a tie breaker for choosing conventions • If fs is small: • Precision t and DG measurements will help guide theory and extraction of fs at LHCb B. Casey, BNM 2008

  18. New Physics and Rare decays b → s: Once everyone’s best guess for new physics ~ g s b b→s g: too small to measure DB= Ds = 1 ~ ~ s b s b ~ ~ ~ s g Dms: too small to measure b DB= Ds = 2 ~ ~ s b ~ s b g B. Casey, BNM 2008

  19. New Physics and rare decays b → s: Still everyone’s best guess for new physics. But now need to look where we have a chance to see small effects CPV phases: DB = Ds = 1: b→sss, DB = Ds = 2: fs Interference: b → sl+l- Large SM suppression: Bs→ mm (B+ → tn) (K→pnn) (Closely related to b → s) B. Casey, BNM 2008

  20. Radiative decay: B → Vmm 18.5 ± 6.7 K* 7.5 ± 3.6 f 1 fb-1: ~26 B→Vmm events 5 fb-1: ~250 events (CDF + DØ) Should add not-trivial stats for world average AFB in next few years B. Casey, BNM 2008

  21. Annihilation: Bs→mm ~most important thing we are doing in the Tevatron B program right now 2 fb-1 results: Low lum, old silicon Pretend there is a CDF plot here high lum, new silicon B. Casey, BNM 2008

  22. Bs→mmpast and future • Step 1 (0.5-1 fb-1): • Do we understand e(mm)/e(Kmm)? • Not at all trivial since trigger is tight, pT distributions are different, and B pT not well known • Can we reduce combinatoric background? • Step 2 (1-2 fb-1): • Multivariate background suppression • B→h+h- (CDF) • Step 3 (2-4 fb-1): • Smarter pre-selection • B→h+h- ? (CDF and DØ) • Fake tracks at high lum (DØ) • Specific cuts to remove B background B. Casey, BNM 2008

  23. Bs→mmversus B →tt • No serious attempt (yet) at Bs→tt at Tevatron • At B factories? • BaBar limit uses fully reconstructed B data set → not interesting (4 x 10-3) • Can it be done without reconstructing the other B? • Look at Belle note 296 for examples of finding back-to-back tau’s in hadronic events • 4S/5S lum ratio indicates Bd decay just as possible as Bs decay • If there is a factor of 10 enhancement, Tevatron mm + B factory tt would be very interesting B. Casey, BNM 2008

  24. Future flavor at fermilab • Many very exciting questions will be difficult to answer at LHC (or at least require very large data sets) • How does the higgs couple to fermions? • How does TeV scale physics influence flavor? • Is there lepton flavor violation at the TeV scale? • Leptogenesis? • Beyond TeV scale physics? B. Casey, BNM 2008

  25. Future flavor at fermilab • ~Current accelerator complex: • Low mass higgs → bb at Tevatron • NOvA • m → e conversion • Project X: • sensitivity to minimal flavor violation signatures in kaons • Next generation m → e conversion • Neutrino CPV • Long baseline to DUSEL (proton decay) • dedicated fixed target tau/charm Possibility for a very exciting US accelerator-based program complementing or competing with flavor programs in Asia/Europe B. Casey, BNM 2008

  26. Conclusions • Many exciting Bs results from Tevatron and more to come • Results from the 5S can have a very significant impact, particularly on CPV measurements • When you think of fs, think big • Potential for exciting accelerator based program next decade in US that will complement super B factory and LHC results B. Casey, BNM 2008

More Related