1 / 52

B masses, lifetimes and mixing at the Tevatron

B masses, lifetimes and mixing at the Tevatron. XXXXth Rencontres de Moriond La Thuile, March 12-19 2005      Franco Bedeschi INFN-Pisa. OUTLINE. Tevatron and Detectors Data sets Masses Lifetimes Mixing. Data sets. CDF/D0 use data collected in the period 2002-2004

eadoin
Download Presentation

B masses, lifetimes and mixing at the Tevatron

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. B masses, lifetimes and mixing at the Tevatron XXXXth Rencontres de Moriond La Thuile, March 12-19 2005      Franco Bedeschi INFN-Pisa OUTLINE • Tevatron and Detectors • Data sets • Masses • Lifetimes • Mixing F. Bedeschi, INFN-Pisa

  2. Data sets • CDF/D0 use data collected in the period 2002-2004 • ~ 600 pb-1 recorded • D0: • ~ 220-450 pb-1 used for B physics • CDF: • ~ 240-360 pb-1 used for B physics • Lost ~ 100 pb-1 due to Central Tracking Chamber ageing problem • Now completely resolved F. Bedeschi, INFN-Pisa

  3. Data samples • J/y samples: • Millions! ~ 20% are from B’s • Reconstruct exclusive B/LBJ/y K/L0 modes • Semi-leptonic B  D ln X samples: • ~ 100 K events with fully reconstructed D • D0 has larger muon acceptance • CDF lowers lepton trigger pt by requiring additional displaced track • Fully hadronic decays (CDF only) • ~ 10 K events fully reconstructed B’s • Requires trigger on secondary vertex (SVT) F. Bedeschi, INFN-Pisa

  4. B hadron lifetimes C. Tarantino, hep-ph/0310241 October 2003 • B hadron decays dominated by b-quark decay • Effect of spectator quarks can be included with perturbative expansions in terms of 1/mb (HQE) • Expect small differences between lifetimes of different species • Non-perturbative ME from lattice, Wilson coeff. from perturbative QCD • NLO improves agreement • Ratios reduce theory uncertainties LO NLO Experiment Theory F. Bedeschi, INFN-Pisa

  5. Lifetimes • HFAG 2004 averages as of summer 04 (hep-ex/0412073 Jan. 2005) • B0, B+ dominated by BaBar/Belle (latest not yet included in HFAG average) • Best result from Belle:  calibration result for Tevatron measurements  • B0: 1.534±0.008±0.010, B+: 1.635±0.011±0.011, t(B+)/t(B0)=1.066±0.008±0.008 • Bs, LB: dominated by CDF/D0, LEP • t(B+)/t(B0): No Tevatron Run II results included • Bs: Includes Run II D0 J/yf (220 pb-1), CDF J/yf (240 pb-1) • See talk by S. Burdin for new DGs/Gs measurements • LB: Includes Run II D0 J/yL (250 pb-1), CDF J/yL (65 pb-1) (*)Gabbiani et al.,hep-ph/0407004 Oct.2004 F. Bedeschi, INFN-Pisa

  6. 260 pb-1 13,300 Signal events Lifetimes with BlnDX modes • Highest statistics samples • Difficult systematics: • Sample composition for Bu, Bd • Cross talk from D**, D* • Backgrounds: • Combinatorial • Physical: BD(*)D(*) • Prompt: c-cbar, b-bbar, D+fake • Recent result from CDF with low statistics lepton pt > 8 GeV sample t(B+) = 1.653±0.029±0.032 ps, t(B0) = 1.473±0.036±0.054 ps • t(B+)/t(B0) = 1.123±0.040±0.040 • Very high statistics secondary vertex triggered sample still under study F. Bedeschi, INFN-Pisa

  7. 440 pb-1 Lifetime ratio with BlnDX modes • D0: new method to determine t(B+)/t(B0): • Fit the ratio of the lifetime distributions • Many systematics are reduced in the ratio • Best measurement of this ratio at Tevatron t(B+)/t(B0) =1.08±0.016±0.014 ~ 126,000 D0 F. Bedeschi, INFN-Pisa

  8. Ds D+ RS WS M(fp) 400 pb-1 Lifetimes with BslnDsX modes • First high statistics Bs lifetime measurement from D0 • Use Ds+ fp+ decay • Difficult background systematics: • Combinatorial • Physical: BD(*)D(*) • Prompt: c-cbar, b-bbar, D+fake • Currently best measurement t(Bs) = 1.420±0.043±0.057 ps NDs = 5153 Systematics Summary (mm) F. Bedeschi, INFN-Pisa

  9. B- ct-efficiency B-D0p- Lifetime with hadronic decays • CDF: • First measurement with Secondary Vertex Trigger biased samples • Trigger/analysis ct-efficiency curves from “realistic” MC • Check by emulating trigger cuts on B+ J/y K+ • Use several final states • B±: D0p±[8380 ev.] (D0Kp) • B0: D±p [5280 ev.](D±Kpp) D± 3p [4173 ev.] (D±Kpp) • Bs: Ds p± [465 ev.] (Dsfp) Ds 3p [133 ev.] (Dsfp) • Important for Dms measurement F. Bedeschi, INFN-Pisa

  10. Lifetimes with hadronic decays Bs B+ • More statistical power than J/y modes • Slightly larger systematics • Efficiency curve • backgrounds t(B+) = 1.661±0.027±0.013 ps t(B0) = 1.511±0.023±0.013 ps t(Bs) = 1.598±0.097±0.017 ps Systematics (mm) Bs B+ F. Bedeschi, INFN-Pisa

  11. Lifetimes: new results summary • Many new results not included in HFAG 2004 averages • To come: • CDF high statistics semi-leptonic results • Ratios in several modes • Updates on LB Included in HFAG averages Red = Very recent! Just approved F. Bedeschi, INFN-Pisa

  12. B mixing • Neutral B’s mix: • SM interpretation with box diagrams • Frequency Dmd,s |Vtd,s|2 • Constraints to CKM weak due to theory uncertainties • Theory accuracy ~5% in ratio Dmd/Dms • Bd mixing measured and established clearly • LEP, CDF-1, CDF-2, D0-2, BaBar, Belle • Bs mixing not observed • Limits set by LEP, SLD, CDF-1 F. Bedeschi, INFN-Pisa

  13. B mixing • Basic ingredients for the measurement: • High statistics samples of neutral B’s in flavor specific decays • CDF: J/yK, Dp, lnDX • D0:J/yK, lnDX • Proper decay length reconstruction • Fully reconstructed modes provide better accuracy • Tagging of flavor at production (flavor tagging) • Key problem at the Tevatron! • Equivalent statistical power: N eD2 • e = tagger efficiency • D = tagger dilution = 2*h-1 (h = probability of correct tag) • Measure: A(t) = (Nnm-Nm)/ N = D cos(Dm t) • Nnm (Nm): number of B’s with same (different) flavor at production and decay • Mixing measurement calibrates dilution • Impossible for Bs until oscillation observed F. Bedeschi, INFN-Pisa

  14. Bd Mixing • HFAG Summary Based on result presented in summer 2004 • World Average dominated by BaBar/Belle F. Bedeschi, INFN-Pisa

  15. ,K+ Flavor tagging Signal side • Opposite side techniques (OST): • CDF: total eD2 ~ 1.1 – 1.4 % • Soft Muon Tag • Soft Electron Tag • Jet Charge Tag • D0: eD2 ~ 1.1% • Enhanced muon tag eD2 ~ 1.1% • Add-in correlations with associated jet in likelihood • Same side techniques (SST): • Sign of nearby track is correlated to b type (SST) • Tagging power depends on B type • PID helps for Bs • eD2 ~ 1% for CDF&D0 in Bd Opposite side B F. Bedeschi, INFN-Pisa

  16. Fit projection lD sample JQT (Vertex) Bd mixing • 2 recent results from CDF using 355 pb-1 and OST • Semi-leptonic sample: 124k lD0 (24k lD*+), 53k lD+ • Dmd = 0.497 ± 0.028(stat.) ± 0.015(syst.) ps-1 • Hadronic sample: 5.3k yK+, 2.2k yK+, 6.2k D0p-, 5.6k D-p+ • Dmd = 0.503 ± 0.063(stat.) ± 0.015(syst.) ps-1 Average all taggers F. Bedeschi, INFN-Pisa

  17. Bd Mixing • These results obtained using many features important for Bs mixing • Unbinned fit • Parametrized dilutions • Calibrate dilutions • Test amplitude scan on fully reconstructed Bd • Fit D*A*cos(Dm t) at fixed Dm • Expect A=1 for Dm ~ Dmd • Limit (95% CL): • Dm such that A+1.645sA = 1 • Sensitivity: Dm such that 1.645sA =1 Limit Sensitivity H. G. Moser, A. Roussarie, NIM A384 (1997) F. Bedeschi, INFN-Pisa

  18. Bs mixing SM Fit (2004): Dms = 18.3 ± 1.6 ps-1 • Tevatron experiments do not have yet sensitivity for observation of SM prediction • New results: • CDF: • Limit with combined fully reconstructed and semi-leptonic modes (this talk) • D0: • Limit with semi-leptonic modes (S. Burdin talk) F. Bedeschi, INFN-Pisa

  19. hadronic peaks semi peaks CDF: Bs mixing (signals) • Hadronic analysis: BsDsp • ~ 900 events • Cross-check with hadronic lifetime analysis (independent group) • Semi-leptonic analysis: BsDsln • ~ 7.5k events • Cross-check with parallel independent analysis Right sign Wrong sign F. Bedeschi, INFN-Pisa

  20. BsDsp (Dsfp) • Details (K-f) • (ct-eff) • (sct-SF) • t (had, lD) CDF: Bs mixing (cross-checks) • Mass and lifetime projections • Mass and lifetime consistent with World Avg. values/D0 tBs = 1.518±0.090 Dsfp F. Bedeschi, INFN-Pisa

  21. CDF: Bs Mixing (scans-1) • Amplitude scans all statistics dominated Semi-leptonic Hadronic F. Bedeschi, INFN-Pisa

  22. Old projections CDF: Bs mixing (scans-2) • Combined scan results: • 7.9 ps-1 95% CL limit • Sensitivity: 8.4 ps-1 • Effect on World Average: • Limit: 14.5  14.5 ps-1 • Sensitivity: 18.2  18.6 ps-1 CDF Run 1 limit F. Bedeschi, INFN-Pisa

  23. Conclusions • Many new results from the Tevatron • Major new results in Bs sector • More Bs results from D0 (talk by S. Burdin) • Lifetime updated and more to come • First CDF/D0 Bs mixing limits • Lower than expectations • Additional improvements could reduce the statistical error on the amplitude by up to a factor two with same data set • It is a very difficult analysis, but now we are in business F. Bedeschi, INFN-Pisa

  24. Backup Backup Slides F. Bedeschi, INFN-Pisa

  25. Tevatron • Tevatron is delivering good luminosity consistent with 2002 predictions • ~ 750 pb-1 delivered per experiment since start of Run II • Peak luminosity in excess of 1032 Best 1.1x1032 • Injections around 1032 are now rather common occurrence • Good Recycler performance F. Bedeschi, INFN-Pisa

  26. Detectors • CDF: • Excellent mass resolution • Particle ID: dE/dx, TOF • Tracking triggers (Hadronic B’s): • L1: Tracks • L2: Secondary vertex • D0: • Excellent muon and tracking coverage • Tracking up to |h|<3 • Muons up to |h|<2 F. Bedeschi, INFN-Pisa

  27. Masses • D0: • Old 04 results: • Narrow B** resonances • B--> narrow D** sates (D1, D2) • Bc meson in semileptonic decays • New winter 05 results • D**s states • CDF: • Old 04 results: • D+ Ds mass difference • D** states D1, D2 • B meson masses • New winter 05 results: • Hadronic Bc • B** fits (PR plot) F. Bedeschi, INFN-Pisa

  28. B hadron masses • B mass determination • Use clean J/yK modes • Accurate tuning of momentum scale with large J/y sample CDF CDF D0 D0 F. Bedeschi, INFN-Pisa

  29. Masses • Run II results ~ or better of current world averages • CDF has best results due to better tracking resolution • Close to being systematics dominated F. Bedeschi, INFN-Pisa

  30. 230 pb-1 X (3872) • CDF (11.6s) and D0 (5.2s) confirm X (3872) observations from the B factories • CDF measures large prompt fraction • fB(X) = 16.1±4.9±2.0% • fB(y(2S)) = 28.3±1.0±0.7% F. Bedeschi, INFN-Pisa

  31. Masses • Many results not covered in this talk: • Charmless two body decays  link • Bc in fully and partially reconstructed modes (next talk) • Measurements of D** and B** narrow resonances  link • Pentaquark searches  link • Charmed baryons  link F. Bedeschi, INFN-Pisa

  32.  back B hh • Several new results based on this sample presented at ICHEP last summer • Branching fractions • Integrated CP asymmetries F. Bedeschi, INFN-Pisa

  33.  back Bhh • Branching ratios and CP asymmetry • Rare two body decay modes F. Bedeschi, INFN-Pisa

  34.  back Bfh • CDF: B+ fK+ • ACP = -0.07 ± 0.17 ± 0.05 (BaBar: 0.054 ± 0.056 ± 0.012) • BR(B+ fK+) = (7.2 ± 1.3 ± 0.7)x10-6 (HFAG: (9.0 ± 0.7)x10-6) • CDF: Bs ff • BR(Bsff) = (1.4 ± 0.6 ± 0.2 ± 0.5(norm))x10-5 (QCD fact. 3.68x10-5) (NF fact. 1.79x10-5) First observation! F. Bedeschi, INFN-Pisa

  35.  back D** mesons 4 G300MeV • CDF: Mass and width • D0: B.R. Belle hep-ex/0307021 F. Bedeschi, INFN-Pisa

  36.  back B** mesons • D0: • First high statistics observation • CDF: • Preliminary results consistent with D0 F. Bedeschi, INFN-Pisa

  37.  back Pentaquark searches • Pentaquark signal searched by CDF • No evidence observed so far • Set limits on production cross-section F. Bedeschi, INFN-Pisa

  38.  back Charm baryons • Charm baryons observed for first time at p p-bar collider by CDF F. Bedeschi, INFN-Pisa

  39.  back Lifetimes • D0: • Old 04 results: • Bs lifetime from psi phi mode (Bs/B0) • Bd/Bu lifetime ratio • New winter 05 results: • DGs/Gs results and polarization studies • Bs lifetime using DslvX • CDF: • Old 04 results: • Bs/Bd polarization and lifetime difference • Exclusive psiK lifetimes & Bu/Bd lifetime ratio • New winter 05 results: • Lifetimes from semileptonic 8 GeV data • Lifetimes from hadronic modes F. Bedeschi, INFN-Pisa

  40. Lifetimes with J/y K modes • Cleanest channels, but statistics limited: • Best Tevatron results from CDF (240 pb-1) • B+ yK+, B0 yK*, K0S, Bsyf • Main background from prompt y + tracks • No kinematic uncertainty • Systematics at level of B factories t(B+) = 1.662±0.033±0.008, t(B0) = 1.539±0.051±0.008 t(Bs) = 1.369±0.100±0.009 NBs = 256 F. Bedeschi, INFN-Pisa

  41. Mixing • D0: • Old 04 results: • B0 oscillation with OS mu tag • B0 oscillation with SS tag • B0 oscillation with OS mu tag, Jet Charge and SST • New winter 05 results: • Dms limit from semileptonic decays • CDF: • Old 04 results: • B0 oscillations with SST in fully reconstructed decays • B0 oscillations with OST in semileptonic decays • B0 oscillation with SST in semileptonic decays • New winter 05 results: • B0 mixing with OST in hadronic decays • B0 mixing with OST in semileptonic decays • Bs mixing with OST in hadronic decays • Bs mixing with OST in semileptonic decays F. Bedeschi, INFN-Pisa

  42.  back CDF: Bs signals 3p Hadronic samples Wide range Fit projection K*K F. Bedeschi, INFN-Pisa

  43.  back CDF: Bs signalssemi-leptonic samples 3p K*K F. Bedeschi, INFN-Pisa

  44.  back CDF: Bs lnDs k-factors • K-factor = pt(lD)/pt(B) • Binned by M(lD) DsK*K Dsppp Dsfp F. Bedeschi, INFN-Pisa

  45.  back CDF: Bs ct-efficiencies • Semi-leptonic sample • All ct efficiencies obtained with realistic MC • Cross check: lifetimes consistent with D0/WA Dsppp Dsfp DsK*K F. Bedeschi, INFN-Pisa

  46.  back CDF: Bs ct-efficiencies • Hadronic sample • All ct efficiencies obtained with realistic MC • Cross check: lifetimes consistent with D0/WA Dsfp DsK*K Dsppp F. Bedeschi, INFN-Pisa

  47. Total Signal Combin. Ph/Pr. Bck Total Signal Combin. Ph/Pr. Bck Total Signal Combin. Ph/Pr. Bck  back CDF: Bs lifetime checkssemi-leptonic sample • Raw lifetimes from mixing fit – not good for averaging • Average: tB = 1.477±0.032 ps no systematics evaluated • D0:t(Bs) = 1.420±0.043±0.057 ps, WA:t(Bs) = 1.469 ± 0.059 ps tBs = 1.410±0.086 tBs = 1.381±0.067 tBs = 1.521±0.040 Dsppp Dsfp DsK*K F. Bedeschi, INFN-Pisa

  48.  back CDF: Bs lifetime checkshadronic sample • Raw lifetimes from mixing fit – not good for averaging • Average: tB = 1.515±0.070 ps no systematics evaluated • D0:t(Bs) = 1.420±0.043±0.057 ps, WA:t(Bs) = 1.469 ± 0.059 ps tB = 1.377±0.186 tB = 1.550±0.131 Dsppp DsK*K F. Bedeschi, INFN-Pisa

  49.  back CDF: Bs s(ct) scale factors • s(ct) scale factor distributions in semi-leptonic sample • Calculation from large data control sample • Parameterization in terms of many variables Dsppp Dsfp DsK*K F. Bedeschi, INFN-Pisa

  50.  back CDF: Bs s(ct) scale factors • s(ct) scale factor distributions in the hadronic sample • Calculation from large data control sample • Parameterization in terms of many variables Dsppp Dsfp DsK*K F. Bedeschi, INFN-Pisa

More Related