Tevatron CDF Tevatron Main Injector Recycler Main Injector

１．はじめに １．１．Tevatron CDF Tevatron Main Injector + Recycler Main Injector D 0 反陽子生成率の向上 ビーム強度の増加 Recycler 反陽子の再利用 今後 Run IIa ２００１年３月より稼動 6× 6@900 Ge. V ⇒ 36× 36@980 Ge. V 5. 2× 1031 cm-2 sec-1 2003年８月１１日 （4. 1× 1031 cm-2 sec-1 2003年３月 春の学会) (1. 6 × 1031 cm-2 sec-1 Run 1 b) 300 pb-1 Delivered 250 pb-1 On Tape 130 pb-1 Analysis

1. 2. CDF(その 1) CDF Detector Overview New Central Tracker (COT) New Plug Calorimeter 1. 3 < | | < 3. 5 Forward Calorimeter 3. 5 < | | < 5. 1 To. F counter for K/ separation Placed right before the Solenoid Muon Detector More Coverage SVX: Acceptance increase |z 0| < 30 g 45 cm L 00: Vertex resolution ISL: | | < 2. 0

1. 2. CDF(その 2) 1 = Improved Si coverage TOF | | < 2 8 layers =2 =3 Central Drift Chamber 96 layers Time of Flight Expanded coverage Forward Calorimeter Trigger COT tracks at L 1 Silicon tracks at L 2

2. 電弱相互作用 2. 1. （その 1） σZ • Br(Z→e+e−) = 267. 0 ± 6. 3 ± 15. 2 ± 16. 0 pb stat. syst. lumi. σW • Br(W→e ) = 2. 64 ± 0. 01 ± 0. 09 ± 0. 16 nb stat. syst. lumi. σZ • Br(Z→μ+μ−) = 246 ± 12 ± 15 pb stat. syst. lumi. W·B(W μ ) = 2. 64 0. 02 0. 16 nb stat syst lum

2. 1. (その 2) Z 0 τeτh ØWe have a clear Z 0 e h signal. ØFurther study of backgrounds is underway. Not only interesting as an EWK measurement, it is important for Higgs and SUSYsearches. W→τν Look for jet within narrow 10 degree cone Isolated within wider 30 degree cone p. T( ) > 25 Ge. V ETmiss > 25 Ge. V Ncand = 2345 σW • Br(W→ ) = 2. 62 ± 0. 07 ± 0. 21 ± 0. 16 nb stat. syst. lumi.

2. 1. (その 3) W & Z Cross Sections vs. ECM Our new measurements NNLO

2. 1. (その 4) Lepton Universality in W Decay τ-e μ-e g ge = 0. 99 0. 02 stat 0. 04 sys = Number of candidates = Number of background events = Acceptance for = Efficiency for = R= (pp->W) G(Z) G(W->l l) (pp->Z) G(Z->ll) G(W)

2. 2. W/ Z (その 1) 10 a. SE 岡山大 谷本 Study of Wγ production with W→μν at CDF in Run II Require central ET( ) > 7 Ge. V ΔR(l- ) = √(Δη 2+ΔΦ 2) >0. 7 Zγ Wγ 133 seen 47 seen 141 expected 43 expected σ • Br = 17. 2 ± 2. 2 (stat. ) ± 2. 0 (syst. ) ± 1. 1(lumi. ) pb pb σ • Br = 5. 8 ± 1. 0 (stat. ) ± 0. 4 (syst. ) ± 0. 4 (lumi. )

2. 2. W/ Z (その 2) Wγ and Zγ couplings Cross sections and mass spectra are consistent with SM

2. 3. W W Higgs, SUSY Search isolated lepton pair opposite-charge, high p. T ETmiss Z veto events with jets ∫L = 126 pb-1 5 events seen (5 with 1. 2 ± 0. 3 BG events in Run I @ ∫L = 108 pb-1) 9. 2 events expected (2. 3 background, 6. 9 ± 1. 5 W W → l l’ ’)

3. Bの物理 B Physics at Hadron Machines b’s produced by strong interaction, decay by weak interaction Enormous cross-section ~100 barn total ~3 -5 barn “reconstructable” At 4 x 1031 cm-2 s-1 ~150 Hz of reconstructable BB!! All B species produced Bu, Bd, Bs, Bc, b, … Large inelastic background Triggering and reconstruction are challenging

3. 1. 寿 命（その 1） B Hadron Lifetimes Heavy Flavor Averaging Group All lifetimes equal in spectator model. l Differences from interference & other nonspectator effects Heavy Quark Expansion predicts the lifetimes for different B hadron species Measurements: l B 0, B+ lifetimes measured to better than 1%! l Bs known to about 4% l LEP/CDF (Run I) b lifetime lower than HQE prediction Tevatron can contribute to Bs, Bc and b (and other b-baryon) lifetimes. http: //www. slac. stanford. edu/xorg/hfag/index. html

(B 0) (B+ ) 3. 1. 寿 命（その 2） B+, B 0 Lifetimes in J/ Modes 1. 51 0. 06(stat. ) 0. 02 (syst. ) ps 1. 63 0. 05(stat. ) 0. 04 (syst. ) ps on low p. T dimuons (1. 5 -2 Ge. V/ ) l. Fully reconstruct ü J/ , (2 s) + ü B+ J/ K+ ü B 0 J/ K*, J/ Ks ü Bs J/ ü b J/ l. Trigger Proper decay length:

3. 1. 寿 命（その 3） Bs Meson Lifetime Bs→J/ψ Φ with J/ψ→μ+μ- and Φ→K+KB+→ J/ΨK+, B 0 →J/ΨK*0 check technique, systematics Bs lifetime - PDG 1. 461 ± 0. 057 ps 1. 33 ± 0. 14(stat) ± 0. 02(sys) ps

3. 1. 寿 命（その 4） b Lifetime Use fully reconstructed b J/ with J/ + and p Previous LEP/CDF measurements used semileptonic b cl Systematics different primary 65 pb-1 Lxy +p 46 9 signal First lifetime from fully reconstructed Λb decay!

3. 2. 質 量 B Hadron Masses Measure masses using fully reconstructed B J/ X modes High statistics J/ + and (2 s) J/ + for calibration. Systematic uncertainty from tracking momentum scale Magnetic field Material (energy loss) B+ and B 0 consistent with world average. Bs and b measurements are world’s best. CDF result: M(Bs)=5365. 50 1. 60 Me. V World average: M(Bs)=5369. 60 2. 40 Me. V CDF result: M( b)=5620. 4 2. 0 Me. V World average: M( b)=5624. 4 9. 0 Me. V

3. 3. 分岐比（その 1） Silicon Vertex Tracker (SVT) SVT incorporates silicon info in the Level 2 trigger… select events with large impact parameter! Secondary Vertex Lxy Primary Vertex 35 m 33 m resol beam s = 48 m B PT(B) 5 Ge. V Lxy 450 m -500 d = impact parameter Uses fitted beamline impact parameter per track System is deadtimeless: ~25 sec/event for readout clustering + track fitting + -250 0 250 500 SVT impact parameter ( m)

3. 3. 分岐比（その 2） a B h+h tree b V ub charmless two-body decays longer term Bs modes help extract unitarity angle Signal is a combination of: B 0 + BR~5 x 10 -6 (4 s), Tevatron 0 + -5 B K BR~2 x 10 Bs K+K BR~5 x 10 -5 Tevatron + -5 Bs K BR~1 x 10 Requirements } } pengui n 280 26 events = 5. 252(4) Ge. V/c 2 = 41. 0(4. 0) Me. Vc 2 Displaced track trigger Good mass resolution Particle ID (d. E/dx) + hypothesis M( )

3. 3. 分岐比（その 3） Simulation Bd K Bs KK Bd Bs K 320 60 events = 5. 252(2) Ge. V/c 2 = 41. 1(1. 9) Me. V/c 2 M( ) BR(Bs K+K ) Fitted contributions: mode Yield (65 pb-1) B 0 K 148 17(stat. ) 17(syst) B 0 39 14(stat. ) 17(syst) Bs KK 90 17(stat. ) 17(syst) Bs K 3 11(stat. ) 17(syst) kinematics & d. E/dx to separate contributions CDF Run. II Preliminary D* D 0 , Sep. ~1. 3 D 0 K (d. E/dx – d. E/dx( ))/ (d. E/dx) First observation of Bs K+K !! Result:

3. 3. 分岐比（その 4） Bs Ds + Golden mode for Bs mixing Bs Ds with Ds + and K K+ BR(Bs Ds ) = ( 4. 8 1. 2 1. 8 0. 6) 10 -3 New measurement ! (Stat) (BR) (sys) (fs/fd) Previous limit set by OPAL: BR (Bs Ds ) < 13% BR result uses less data than shown in plot.

3. 3. 分岐比（その 5） Bs Sensitivity Estimate Current performance: hadronic mode only S=1600 events/fb-1 (i. e. effective for produce+trigger+recon) S/B = 2/1 D 2 = 4% t = 67 fs 2 sensitivity for ms =15 ps-1 with ~0. 5 fb-1 of data surpass the current world average With “modest” improvements S=2000 fb (improve trigger, reconstruct more modes) S/B = 2/1 (unchanged) D 2 = 5% (kaon tagging) t = 50 fs (event-by-event vertex + L 00) 5 sensitivity for ms =18 ps-1 with ~1. 7 fb-1 of data 5 sensitivity for ms =24 ps-1 with ~3. 2 fb-1 of data ü ms=24 ps-1 “covers” the expected region based upon indirect fits. This is a difficult measurement.

3. 3. 分岐比（その 6） CDF 1 event in Bs and Bd search window Expected bkg 0. 54 0. 20 (for Bs) 0. 59 0. 22 (for Bd) @95% CL

3. 3. 分岐比（その 7） b c with c p. K Backgrounds: real B decays Reconstruct as p: Bd D + K+ + Use MC to parametrize the shape. Ø Data to normalize the amplitude Ø Dominant backgrounds are real heavy flavor Ø proton particle ID (d. E/dx) improves S/B Ø Fitted signal: Measure: New Result ! BR(Lb Lc ) = (6. 0 1. 0(stat) 0. 8(sys) 2. 1(BR) ) 10 -3

3. 3. 分岐比（その 8） Br( b J/ ) In progress 11 p. SJ 6 岡山大 山下 Study of