H.Evans Tevatron Connection: 24-Jun-05 1 B-Physics at DØ Recent Results & Plans Hal Evans(for the DØ B group)Columbia U. 1.B-Physics & the DØ Detector 2.Recent B-Physics Results  Rare Decays  Lifetimes  Mixing 3.Planning for the Future

H.Evans Tevatron Connection: 24-Jun-05 2 The Data Set Analyses Presented Here → ~470 pb -1 Coming Soon: 610 pb -1

H.Evans Tevatron Connection: 24-Jun-05 3 DØ Detector (the cartoon) Central Scintillator Forward Mini- drift chamb’s Forward Scint Shielding Tracking: Solenoid(2T), Silicon,FiberTracker,Preshowers New Electronics,Trigger,DAQ Calorimeter Central PDTs

H.Evans Tevatron Connection: 24-Jun-05 4 Tracking 2 T Magnetic Field  track reco to P T = 180 MeV Silicon: 2.7 – 9.5 cm (barrel)  6 barrels / 4 layers + disks  793K chan’s (most 2-sided)  Layer 0 this fall (r ~ 1.7 cm) Fiber Tracker: 20 – 51 cm  8 double layers: axial & stereo  77K channels Pre-Shower  scintillating strips  central & forward / axial & stereo Large Acceptance: |  | < pb -1  ~ 60 MeV ~10  m ~55  m (P t = 1GeV)

H.Evans Tevatron Connection: 24-Jun-05 5 Muons  = 2 P > 1.5 GeV P > 3.5 GeV Forward Muon Efficiency Trigger Counters Mini-Drift Tubes Efficiency Luminosity (x10 30 ) 100% 90% 100% 90%  Large Coverage|  | < 2  High Efficiency  High Purity>60% 1- L1

H.Evans Tevatron Connection: 24-Jun-05 6 Trigger Main B-Physics Triggers Single- and Di-Muon B s Mixing Data Set  ~67%Di-Muon  ~25%Single-Muon  ~8%other (  +jet) CAL c/f PS CFT SMT MU FPD L1Cal L1PS L1CTT L1Mu L1FPD L2Cal L2PS L2CTT L2STT L2Mu Global L2 Framework Detector Lumi Level 1Level MHz2.5 kHz1 kHz Level 3 CalTrk 50 Hz Typical Rates (Hz) at L = 4  cm -2 s -1 TriggerL1L2L3 dimuon50154 single mu Total L3 limit ~ 50 Hz  prescale !

H.Evans Tevatron Connection: 24-Jun-05 7 DØ B-Physics Results  Differential X-Section160 pb -1 PRL 94 (2005) B s → D s1 (2536)  v X485 pb -1 preliminary B c Semileptonic210 pb -1 preliminary B → D ** 250 pb -1 preliminary B ** 350 pb -1 preliminary X(3872)230 pb -1 PRL 93 (2004) D s →   and D - →   508 pb -1 preliminary B s →  +  -  300 pb -1 preliminary B s →  +  pb -1 preliminary 240 pb -1 PRL 94 (2005) B s  /  450 pb -1 preliminary B s → D s  X Lifetime400 pb -1 preliminary B + /B 0 Lifetime Ratio440 pb -1 PRL 94 (2005)  b → J/   Lifetime250 pb -1 PRL 94 (2005) B s → J/   Lifetime220 pb -1 PRL 94 (2005) B s Mixing using D s (  )  X and OST460 pb -1 preliminary B s → D s (K * K)  X Reconstruction200 pb -1 preliminary B d Mixing250 pb -1 preliminary

H.Evans Tevatron Connection: 24-Jun-05 8 B’s Galore ! Modeevts / 100pb -1 J/    +  M B +  J/  K B d  J/  K *0 740 B d  J/  K 0 S 40 B s  J/   100  b  J/   25 B c  J/   X65 X(3872)  J/   +  B  D **  v210 B **  B  150 B s  D s1  X4 B +  D 0  + X46.2 K B d  D* -  + X10 K B s  D s (  )  X2900 B s  D s (K * K)  X2500 B s → D s1 (2536)  v X 485 pb -1 Signal: 18.5 ± 5.5 (3.4  ) D s1 + → D *+ K S 0

H.Evans Tevatron Connection: 24-Jun-05 9 FCNC Heavy Flavor Decays b d,sd,s u,c,t W W v ℓ+ℓ+ ℓ-ℓ- b d,sd,s W W Z ℓ+ℓ+ ℓ-ℓ- b d,sd,s W Z ℓ+ℓ+ ℓ-ℓ- Bs  W Z u,c,t ℓ+ℓ+ ℓ-ℓ- Bs  u,c,t W W Z ℓ+ℓ+ ℓ-ℓ- B s →  +  - B s →  +  -  SM BR = (3.4±1.5)  Enhanced at large tan  (MSSM  tan 6  ) CDF-II: BR < 1.5  SM BR ~ 1.6  Smaller Enhance at large tan  CDF-I: BR < 6.7  D + →  +  -  + SM BR ~ 1.0  (dominated by long distance) Enhanced in e.g. RPV SUSY FOCUS: BR < 8.8  10 -6

H.Evans Tevatron Connection: 24-Jun B s →  +  - and  +  -  Preselection  vertexed  +  - P T  > 2.5 GeV, |  | < 2.0  pair of opp chrg tracks (  )  P T B > 5 GeV Final Selection Discriminants  Isolation of  +  - (  )  Pointing Angle:  (L vtx, P)  L xy Signif: L xy /  L xy Normalization Channels   +  - B + → J/  K +   +  -  B s → J/   Bs→+-Bs→+- Bs→+-Bs→+-  +  - Events closed 300 pb -1

H.Evans Tevatron Connection: 24-Jun Limits ChannelEff wrt Pre-SelN(bgrd)N(data)BR Limit (95% CL)SM Pred + -+ - 38.6%4.3 ±   + - + -  52%5.1 ± 1.0blind1.2  (ave)1.6  B s →  +  - Normalization B s →  +  -  Normalization N Bs = 74 ± 11 B s → J/  

H.Evans Tevatron Connection: 24-Jun D s + →  +  -  + and D + →  +  -  + Select D (s) Signal from  (  +  - )  cand’s w/ Likelihood  D Isolation: P T (D)/  P T (cone)  L xy Signif: S D = L xy /  L xy  Pointing Angle:  (L xy,P T )  Signif Ratio: S  (imp-par)/S D Signal (D s →  MC) Background (M D sidebands) L sig / (L sig + L bgd ) = d 508 pb -1 World Best Limit

H.Evans Tevatron Connection: 24-Jun Lifetime Roundup DØ Lifetime Measurements vs HFAG World Averages errors scaled x10 for display purposes World Best

H.Evans Tevatron Connection: 24-Jun B s → D s  v X Lifetime B s → D s (  )  v X Selection  no lifetime biasing cuts Unbinned logL Fit for  using  signal region  wrong- & right-sign sidebands ( to constrain bgrd PDFs)  f(signal) from Mass fit 300 pb -1 D - →   ± 223 Signal Region evts D s - →   ± 265 ± 450 Right Sign Sideband Wrong Sign Sideband  (Bs) = ± ± ps World Best Measurement ! – HFAG ave now: ± 0.045

H.Evans Tevatron Connection: 24-Jun B s Lifetime Difference B s → J/   (P → V V)  CP-Even:S,D waves  CP-Odd:P wave  relative contributions  CP states of B s Observed Distribution Transversity Angle Fit Þ  b/w M eigenstates Þ R  = |A  (0)| 2 z x y J/  Rest Frame K+K+ K-K- ++ --   x y  Rest Frame  J/  K+K+ K-K- Detector effects CP-Odd CP-Even

H.Evans Tevatron Connection: 24-Jun Fits to Data Data Set: 450 pb -1  9699 candidate events  483±32 B s → J/  (  +  - )  (K + K - )  Fit to: M(B s ), ct 0, cos   Free params  f sig,  ave, R ,  / , M(B s )  + resolution & bgrd params Fit Results

H.Evans Tevatron Connection: 24-Jun Comparing to the SM Flavor Specific Decays also constrain  /   Using PDG  (B s →D s lvX)  Assuming SM  CPV 

H.Evans Tevatron Connection: 24-Jun B s Mixing Analysis Data Selection  B s → D s -  + v X D s - →  (K + K - )  -  no explicit trigger required  some  -dependent cuts (effects ~cancel in Asym) Opposite Side (Muon) Tagger  Q(jet) containing muon  P T rel  Q(  )  Q(secondary vertex) Eff & Dilution from Data   = N tag /N tot = 5.1%  D = 2  - 1 = 44.8% (  = N correct /N tag ) D s →   ± pb -1 Untagged Tagged D - →   5019 ± 292 D s →   675 ± 43

H.Evans Tevatron Connection: 24-Jun Measure Tagging using B d and B +  D 0 X Sample (85% B % B d )  D *0 X Sample (85% B d - 15% B + ) uu ± dd ± 0.021use in B s fits mdmd ± ps -1 (HFAG0.509 ± ps -1 winter 05)

H.Evans Tevatron Connection: 24-Jun B s Results 460 pb -1 Asym vs VPDL DØ Prelim Result 95% CL:  m s > 5.0 ps -1 sensitivity: 4.6 ps -1 DØ Prelim Result 95% CL:  m s > 5.0 ps -1 sensitivity: 4.6 ps -1 Expected Limit Comparison

H.Evans Tevatron Connection: 24-Jun DØ Upgrades for High Luminosity Trigger (mainly L1)  allows viable trigger list as L > 2  L3 Bandwidth Upgrade  current limit for B-Physics triggers is at L3  proposal: add dedicated 50 Hz of output bandwidth Silicon Layer-0  integrated radiation dose  inner SMT layer dies  add new, rad hard Layer-0 at R = 1.7 cm  Impact Param: 55→35  m at 1 GeV Integrated Luminosity (fb -1 ) we are here 2  cm -2 s  cm -2 s -1 ~golf ball size ! dE/dx using SMT

H.Evans Tevatron Connection: 24-Jun Reach in B s Mixing In Review Now (for EPS 05)  add K * K mode  improved tagging (add electrons + more var’s) Toward 1 fb -1 semileptonic sens ~ 12 ps -1 with 1 fb -1s Further Down the Road cover ~full SM range (but need to establish hadronic modes)

H.Evans Tevatron Connection: 24-Jun Lifetime Futures B s Lifetime Projections ModeLumi (fb -1 )Stat (ps)Syst (ps)Tot (ps) D s  X Ds Ds   /  Projections Lumi (fb -1 ) Error on  /  Theory0.12 ± 0.05 Assumes: Layer angle Fit for  /  reduction coming soon 450 pb -1 DØ  fs &  / 

H.Evans Tevatron Connection: 24-Jun More Crystal Ball Gazing Most DØ B-Physics Results are Statistics Limited Rare Decays  reoptimize selections, F-B Asym’s, K S  +  -, K *  +  -, …  broaden charm FCNC analysis  /   3-angle fits, Separate Lifetimes for CP-state ( , D s (*) D s (*) )  Integrated CP asym in semileptonic,  s, … B s Mixing  more modes: K * K,3 ,K s K + B s → D s   better tagging: electrons, more variables  event-by-event likelihood fits (some) Others  B **, D**, D s1 : move from observation → measure properties  J/  &  Polarization and b cross-section  B c semileptonic and hadronic decays  make more use of neutral particles ( ,  0,  c →J/   …)  more decay modes

H.Evans Tevatron Connection: 24-Jun Conclusions (Beginnings ?) DØ Physics Program is Hitting its Stride  detector well-suited to many measurements Several World Best Results  D + →  +  -  + ; B s Lifetime Interesting New Results Just Around the Corner  improved  m s, rare decays, … for EPS 05 DØ Upgrades for High Lumi  Improve Performance  trigger, layer-0, L3 bandwidth upgrade Stay Tuned !

H.Evans Tevatron Connection: 24-Jun Backup Slides

H.Evans Tevatron Connection: 24-Jun Low P T Tracking

H.Evans Tevatron Connection: 24-Jun B →  +  - (  ) Final Discriminants B s →  +  - B s →  +  - 

H.Evans Tevatron Connection: 24-Jun B s Mixing Details