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B physics in CDF

B physics in CDF. Epiphany Conference 2003 on Heavy Flavors Kraków, January 3 rd -6 th. Irene Fiori for the CDF collaboration. Outline. (. ). Accelerator and CDF upgrades New tools for B-physics Prospects for : - CP violation - B mixing - B mass & lifetimes

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B physics in CDF

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  1. B physics in CDF Epiphany Conference 2003 on Heavy Flavors Kraków, January 3rd-6th Irene Fiori for the CDF collaboration

  2. Outline ( ) • Accelerator and CDF upgrades • New tools for B-physics • Prospects for : • - CP violation • - B mixing • - B mass & lifetimes • A look at the very first • Run2 results Tevatron Main Injector and Recycler

  3. What is New at the Tevatron • Main Injector: new injection stage, more efficient anti-p transfer to Tevatron ring • Recycler: new storage ring for reuse anti-p (still commissioning, ready 2004) • Higher collision rate: 396ns crossing time (36x36 bunches) ( 132ns, 108x108) major upgrades in detector, electronics and trigger !!! • Slightly higher C.M. energy: 1.8  1.96 TeV • Higher Inst. Luminosity: 5-10 times higher than in Run 1 • Run plans: Run 2a: L = 5-8  1031cm2 s1 • (L = 10-20  1031cm2 s1 , with Recycler) • Total integrated L = 2fb1 • Run 2b: Total integrated L = 6 - 10fb1 2005 …2008

  4. Tevatron Performance 3.8 x 1031 • Tevatron operations • Startup slow, but progress steady ! • Now:L ~3.5 x 1031 cm-2s-1 • integrating ~ 6. pb-1/week • … still factor 2-3 below planned values • additional improvements (~10-20%) expected from Jan. 3weeks shutdown Initial Luminosity July ‘01 Now • CDF operations • Commissioning: Summer 2001 • Physics data since February 2002 • Running with >90% Silicon integrated • since July 2002 On-tape Luminosity 110 pb -1 • Luminosity (on-tape): • ~20pb-1until June (analyses in this talk) • Additional 90pb-1 July – December • Reach 300- 400 pb-1 by October 2003 July ‘02 Feb ‘02

  5. TeV status andgoals 10–6f 0B NpNpb(6 r r) L H ( l /  *) (1031 cm-2s-1) = 2 *( p+  pb) Accelerator parameters: Integrated Luminosity (fb-1)

  6. Why B physics at Hadron Colliders? • All B species (B, B0, Bs, Bc, b, Sb …) produced • High b-production rate ((bb)50b at TeV energies) • BUT: hidden in 103larger Background !!! (inelastic(pp)  50mb) • Critical detector components: • TRIGGER (large bandwidth, BKG suppression, dead timeless) • Tracking system • good momentum and mass resolution • precise Vertexing (decay length) • Particle IDentification • The new CDF detector has all this : • New Silicon Vertex detector with • extended coverage and 3D tracking • New Trigger capable to identify Secondary Vertices • New TOF detector to separate low PT Kaons from 

  7. CDF Detector in Run II Inherited from Run I: • Central Calorimeter (||<1) • Solenoid (1.4T) Partially New: • Muon system (extended to ||~1.5) New: • Tracking System • - 3D Silicon Tracker (up to ||~2) • - faster Drift Chamber • Plug and Forward Calorimeters • Time-of-Flight (particle ID) • Luminosity monitor • Front End Electronics (for 132ns bunch spacing) • Trigger system (new trigger on displaced vertices)

  8. Quadrant of CDF II Tracker TOF:100ps resolution, 2 sigma K/ separation for tracks below 1.6 GeV/c (significant improvement of Bs flavor tag effectiveness) TIME OF FLIGHT COT: large radius (1.4 m) Drift C. • 96 layers, 100ns drift time • Precise PT above 400 MeV/c • Precise 3D tracking in ||<1 (1/PT) ~ 0.1%GeV –1; (hit)~150m • dE/dx info provides 1 sigma K/ separation above 2 GeV • SVX-II + ISL: 6 (7) layers of double-side silicon (3cm < R < 30cm) • Standalone 3D tracking up to ||= 2 • Very good I.P. resolution: ~30m (~20 m with Layer00) LAYER 00: 1 layer of radiation-hard silicon at very small radius (1.5 cm) (achievable: 45 fs proper time resolution inBs Dsp )

  9. CDF II Trigger System 3 levels: 5 MHz (pp rate) 50 Hz (disk/tape storage rate) almost no dead time (< 10%) • XFT: “EXtremely Fast Tracker” • 2D COT track reconstruction at Level 1 • PT res. DpT/p2T = 2% (GeV-1) • azimuthal angle res. Df = 8 mrad • SVT: “Silicon Vertex Tracker” • precise 2D Silicon+XFT tracking at Level 2 • impact parameter res. d = 35 m • Offline accuracy !! CAL MUON CES COT SVX XFT XCES Matched to L1 ele. and muons XTRP enhanced J/ samples L1 CAL L1 TRACK L1 MUON GLOBAL L1 SVT L2 CAL CDF II can trigger on secondary vertices !! Select large B,D samples !! GLOBAL LEVEL 2 TSI/CLK

  10. COT track ( 2 parameters) 5 SVX coordinates beam spot d Impact Parameter (transverse projection) SVT: Triggering on impact parameters ~150 VME boards • Combines COT tracks (from XFT) with Silicon Hits (via pattern • matching) • Fits track parameters in the transverse plane (d, , PT)with offline res. • All this in ~15ms ! • Allows triggering on displaced impact parameters/vertices • CDF becomes a beauty/charm factory

  11. B triggers: conventional Needspecialized triggers (bb) /(pp)  10-3 CDF Run1, lepton-based triggers: • Di-leptons (, PT 2 GeV/c): B  J/ X, J/   • Single high PT lepton ( 8 GeV/c): B  l  D X Suffer of low BR and not fully rec. final state Nevertheless, many important measurements by CDF 1: B0d mixing, sin(2), B lifetimes, Bc observation, … • Now enhanced, thanks to XFT (precise tracking at L1) : • Reduced (21.5 GeV/c) and more effective PT thresholds • Increased muon and electron coverage • Also J/  ee

  12. XFT performance Efficiency curve: XFT threshold at PT=1.5 GeV/c  = 96.1 ± 0.1 % (L1 trigger) XFT: L1 trigger on tracks better than design resolution pT/p2T = 1.65% (GeV-1)  = 5.1 mrad Offline track XFT track 11 pb-1 53.000 J/  

  13. B triggers: New !! Secondary Vertex CDF 2, displaced tracks triggers: B Decay Length Lxy PT(B)  5 GeV Trigger on tracks significantly displaced from primary vertex Primary Vertex Lxy  450m <d>  100 m Made possible by SVT: precise meas. of track impact parameter at Level 2 2D Secondary Vertices reconstructed online ! d = impact parameter • Two displaced tracks(d > 100m, Lxy cut,  cut) • All hadronic B decays: B (KK), b  p(K), Bs Ds(3) ... • Lots of prompt charm mesons !!! • Lepton plus displaced track • Semileptonic decays at Lower PT ( 4 GeV/c) • Rare B decays …

  14. “All Hadronic B triggers” • Level 1: 2 XFT tracks • PT > 2 GeV •  < 135º • PT1 + PT2 > 5.5 “Multi-body decays” “Two body decays” 1/100 h+ Level 2 h- B0 D d > 100 mm 20º <  < 135º Lxy  200 m dB < 140 mm d > 120 mm 2º <  < 90º Lxy  200 m B B0  p p B0  K p Bs K K Bs p K Lb  p p(K) Bs Dsp Bs Dsp p p B D K/p + Lots of prompt charm decays 1/1000 Level 3 SAME with refined tracks & Mass cuts

  15. SVT performance • I.P. resolution as planned • d = 48 m = 35m  33 m intrinsic D0  Kp used as online monitor of the hadronic SVT triggers transverse beam size • Efficiency S/B  1 90% soon 80%

  16. D0 K D0 KK D0  5670180 2020110 56320490 K mass KK mass  mass Lots of charm from hadronic triggers: With ~10 pb-1 of “hadronic trigger” data: Relative Br. Fractions of Cabibbo suppressed D0 decays : Already competitive with CLEO2 results (10fb-1 @ (4S)) !!!!! (DKK)/(DK) = 11.17  0.48(stat)  0.98 (syst) % (D )/(DK) = 3.37  0.20(stat)  0.16(syst) % O(107) fully reconstructed decays in 2fb-1 •  Foresee a quite interesting charm physics program: • D cross sections, • CP asymmetries and Mixing in D sector, Rare decays, …

  17. What fraction is from B ? D mesons I.P. (d) distribution Measured prompt D vs. Dfrom B Reconstructed D mesons from “hadronic charm trigger”: D K, D0 K, D* D0, Ds  D-mesons Impact Parameter (d) used to discriminate the two components: D B fraction D0K16.4  0.7 % D*D011.4  1.4 % DK11.3  0.5 % Ds34.8  2.8 % D D’s from Primary Vertex have d 0 B d(D)

  18. B physics prospects(with 2fb-1) Both competitive and complementary to B -factories • Bs mixing: Bs →Dsπ(Ds3π)(xsup to 60, with xd meas. one side of U.T.) • Angle : B0→ J/ψ Ks(refine Run1 meas. up to (sen2)  0.05) • CP violation, angleγ: B0→ ππ(πK), Bs→ KK(Kπ) • Angle s and s/ s : Bs→ J/ψ(probe for New Physics) • Precise Lifetimes, Masses, BRfor all B-hadrons: Bs, Bc, Λb … (CDF observed: Bc → J/ψ e(). Now hadronic channels Bc → Bs X can be explored) • HF cross sections (beauty and charm) • Stringent tests of SM … or evidence for new physics !!

  19. Lxy c =  Ingredients for B0s mixing meas. Nunmix(t) – Nmix(t) B0s → D-sπ+(3π)   -  K-K+ Amix(t) = = Dcos(mst) Nunmix(t) + Nmix(t) • Reconstruct the final state • if not CP eigenstate tells B flavor at decay with good S/B(precise tracking, vertexing, particle ID) ;  = PT(B) / M(B) 2. Measure proper decay time: Current limit: ms 14.4 ps-1 T 400 fs Error on B momentum, ~ 15% (semileptonic) negligible (~ 0.5%) for fully reconstructed final states 60 fs (SVX II detector) 45 fs (also Layer 00 is used) 3. Identify the flavor of Bsat production: “B - flavor tagging” algorithms

  20. B Flavor Tagging “Identify the flavor of B at production” OST (opposite side tagging): B’s are produced in pairs  measure flavor of opposite B • JETQ:sign of the weighted average chargeof opposite B-Jet • SLT:identify the soft lepton from semileptonic decay of opposite B • SST (same side tagging): • B0 (B0) is likely to be accompanied close by a + () • Search for the track with minimum PTREL b d d u u B0 + Figure of merit: D2 “tagging effectiveness”  2% = efficiency ; D = “Dilution” = 1 – 2Pmistag • Effective size of sample is reduced by D2 !!

  21. NEW: “Kaon b-taggers” • Exploit K/ separation of new TOF • Well suited for strange B mesons b s s u u B0s K+ Same Side K: aB0s(B0s) is likely to be accompanied close by aK+(K) from fragmentation Opposite Side K: due to bcs it is more likely that a B meson will contain in final state a K than a K+  to identify a B0s look for a K from the decay of the opposite B

  22. TOF performance • TOF resolution (110ps) within 10% of design value Background reduction in KK: Low PT (< 1.5 GeV/c) track pairs before and after a cut on TOF kaon probability x20 bkg reduction, 80% signal efficiency with TOF PID S/N = 1/2.5 S/N = 1/40

  23. B0s mixing: expectations with 2fb-1 xs = ms(B0s) Bs Ds, Ds  Ds  , K*K,  • Signal: 20K (fp only) - 75K (all) events • with SVT hadronic trigger • BR (Ds ) = 0.3 % ; BR (Ds   ) = 0.8 % • Resolution: • (c)= 45 fs (with Layer00) • eD2 = 11.3% (with TOF) • S/B: 0.5-2 (based on CDF I data) S.M. allowed range: 20. < Xs < 35. 5s sensitivity up to: Xs = 63 (S/B = 2/1) Xs = 53 (S/B = 1/2) Can do a precise measurement … or evidence for new physics !

  24. Projections for xs reach with 2fb-1 Optimistic: S/B =2/1 Conservative: S/B =1/2 Xs = 42-63 Xs = 32-53 MC simulation: accounts also for SVT cuts on proper time acceptance, non-Gaussian tails in proper time resolution function

  25. B0s mixing: Run I With 110pb-1of dilepton (,e) data 106870   KK BslDsX Ds    KK 1068( ) +lepton events: 61% Bs + 25% B0+ 15% B+ Opposite side lepton tags prod. flavour (SLT) POS(SS)(t) = 1/(2)exp(-t/)(1  cos(ms·t)) Min -Log Likelihood scan as function of ms shows no statistically significant minimum “Amplitude fit method” used to set lower limit: ms> 5.8 ps-1 @95% C.L. (world combined: ms> 14.4 ps-1 )

  26. First steps towards B0s mixing In ~10 pb-1 of “hadronic trigger” data: We reconstruct lots of Ds: Ds(D)  ;  KK We observe hadronic B decays: B+ D0p+ ; D0 Kp+ ~2400 Ds ~1400 D #B± = 56 ± 12 M(Ds) – M(D+) = 99.28  0.43(stat)  0.27(syst) MeV/c2 • Hadronic Triggers are working !!! • Precise Tracking, Vertexing • Momentum scale calibrated at ~ 0.02% !! PDG average: (99.2  0.5 MeV/c2) Already competitive!!! (CLEO2, E691) Looking forward for a Bs hadronic signal in additional ~ 50pb-1 being analyzed …

  27. 1 B 1   » ) + ( sin (2 ) e D N S 2 Sin(2) in B0J/y Ks N(B0)(t) - N(B0)(t) ACP(t) = = Dsin(2b)sin(Dmd t) N(B0)(t) + N(B0)(t) In Run1 measured: B0  J/ Ks ; J/   sin(2b)=0.79±0.39±0.16 (400 events) sin(2b)=0.91±0.32±0.18 (+60 B0   (2S) Ks) With 2fb-1 can refine this measurement Although: no way to compete with B-Factories ! • N(J/ Ks) from scaling Run I data: • x 20 luminosity 8,000 • x 1.25 tracks at L1 trigger 10,000 • x 2 muon acceptance 20,000 • Trigger on J/  e+e+ 10,000 Stat. Error: Expect: s(sin2b)  0.05 Systematic ~ 0.5xStatistical (scales with control sample statistics) • Combined eD2: from 6.3% to 9.1%(Kaon b-tag) • Same S/B = 1

  28. Measurements with B  h+h- 30 eventsin 10 pb-1 of Hadronic Trigger data with very good signal to noise !! A mixture (1 : 4 : 2 : 0.5 ) of: Bdpp;BdKp; BsKp; BsKK #B s,d= 339 S/B = 3/1 • Strategies for disentangling channels: • Kinematics variables • Invariant mass shape (M ~25 MeV/c2) • Particle I.D. • Oscillation of CP asymmetry ( inv.mass) CDF II simulation Expected N(mixture): ~500 in 100pb-1 (~20K in 2fb-1) —sum BdK BsKK Bd BsK  • Can soon perform interesting measurements: • Relative B. Ratios: Bdpp/Kp ; BsKK/Kp • Direct CP asymmetries in BdKp (self tagging !!) • CP asymmetries in Bdpp(with b-tagging) • Later on: CKM angle !!

  29. u W+ p+ b d B0 p u d d b B0 + Bs K+K angle  from B  h+h- B0 +has two (comparable!) decay amplitudes: Penguin Tree W+ d p+ u u,c,t B0 g d u p d direct CP CP from mixing alone ACP(t) =ACPdircos(Dmd t) +ACPmixsin(Dmd t) ACPdir, ACPmixfunctions of ,, d,(d ei P / Tdecay amplitude) R. Fleischer(PLB 459 (1999) 306): Assume U-spin symmetry (d  s) Similar relation holds for Bs K+K(Dmdreplaced byDms) The 4 asymmetries can be expressed as function of , and P/T amplitude ratio Parameters can be extracted from fit of meas. of ACP(t) for Bd and BsKK Expected (2fb-1) accuracy: () = ±10(stat) ±3(syst) (SU(3) breaking effects)

  30. CDF Run 1: 5812 events • Bs lifetime = 1.34+0.26  0.05 ps • CP even fraction = 0.77  0.1 -0.19 Bs J/  B0s J/  Already 15 events in ~20pb-1 Expected in 2fb–1: ~ 4000 events • CP asymmetry measures the weak phase of Vts (angle s = 2s ) • Expected to be very small in S.M : s 2º  sin(2 s )  0.03 • Require angular analysis to disentangle CP even/odd final states • Prerequisite: have measured xs CDF II reach :s(sin(2 s ))  0.1 with 2fb–1 (between 0.03 and 0.06 with 10fb–1) Observing an asymmetry with 2fb–1 would be unambiguous signal for NEW Physics! • Measure of lifetime difference between two Bs mass eigenstates: s = BsH- BsL Current limit (LEP): s / s < 0.31 (S.M expectation:DG/G = 0.05 - 0.20) Expected uncertainty (depending on even/odd fraction) : (s / s) = 0.05

  31. B masses: preliminary meas. B0BB0s in exclusive J/ channels 18.4/pb B0J/yK0* 18.4/pb Prerequisite: momentum scale was precisely set (@0.02%) using J/ sample (~200K events) BsJ/yf • Bu J/y K+ • Bd J/y K0*(K0*K+p -) • Bs J/y f (fK+K-) Very good S/B More mass plots CDF2 (MeV/c2) DM/sCDF sCDF/sPDG Bu 5280.6 ±1.7 ±1.1 +0.8 4.0 Bd5279.8 ±1.9 ±1.4 +0.24.8 Bs5360.3 ±3.8 ± 2.11.9 18.4/pb BJ/yK Bu 2.1 2.9 • Statistics limited, but compare well with PDG • Systematics already under control. • Precise measurements, soon !!

  32. Lxy B lifetimes c = Lxy /  Crucial: precise Secondary Vertexing Silicon VerteX detector (SVX) PV  = PT(B) / M(B) CDF Run I:full set of precise B-life meas. Competitive with LEP • Inclusive: B  l  D X, B  J/ X • Large statistics, but… • Final state not fully reconstructed • PT(B) has to be corrected from MC • Exclusive: Bs J/, b  J/ • Small syst. • Limited statistics Run II:x50 statistics( 2fb-1, wider silicon and lepton coverage, hadronic triggers) Improve meas. Especially Bc, Bs, b down to ~0.01ps

  33. B lifetimes: preliminary meas. 18pb-1 • Inclusive B lifetime with J/y’s • B J/yX from ~ 28.000 J/ • c = J/y(prompt + non-prompt) + non- J/y • c(B) = 458  10(stat)  11(syst) m • PDG: 469 ± 4 mm J/y from B = 17% • Exclusive B+J/yK+ ct(B+) = 446 ± 43(stat) ±13(syst) mm PDG: 502 ± 5 mm CDF 1: 504 ± 21(stat) ± 6(syst) mm Stat. limited 18pb-1 # B ~ 154 Alignment Resolution function

  34. Bc and b Lb  L+c l -n Lb J/y L Run I: ~20 events BcJ/ye/ Run I: M(Bc) = 6.400.390.13 GeV/c2 t(Bc) = 0.46 +0.18 0.03 ps t(Lb) = 1.32  0.15 0.07 ps -0.16 Run II data 30  8 37 pb-1 Lb J/y L Also hadronic modes: Lb  Lc (Lc pK) Lb pD0p(D0 K) Lb pK / p Run II: better Mass, Lifetime, BR Also exclusive channels: BcJ/ p and fully hadronic:Bc Bsp

  35. Conclusions • The upgraded CDF detector has started taking new data • The B physics potential is great and we expect: • Soon (2003): • Preliminary xsmeasurement • Preliminary results from B  2body • masses, lifetimes, BRs for Charms and Beauties • By end of Run IIa (2fb-1, 2005): • Full resolution xsand sin(2) • Direct and mixing asymmetries in two body decays • Angle  at ~10° possible • By end of Run IIb (~2008) • 5 the statistics of Run IIa !! • 20pb-1 of analyzed data already show interesting results • Lots of Charm and Beauty at CDF in the next years !!

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