CDF
CDF Status and Prospects
Stephen MillerUniversity of Michigan
5th International Conference on Hyperons, Charm and Beauty Hadrons
June 28, 2002
6/28/02 2
CDF CDF Run 2 Physics Program
• Broad range of physics topics includesTop - Mass, Cross section, Single top-
>Vtb
Electroweak - W mass, Di-boson production
QCD - High Et jets, photons,
Di-jets(Mjj)-> Compositeness
Charm - BR’s, Masses, Mixing
Bottom - Rare decays, CKM constraints, Lifetimes, Mixing
Higgs – Discovery/Exclusion
Exotics - Susy, Large Extra dimensions, Z’
• Improve Run 1 measurements (110 pb-1)Expect 2 fb-1 for Run 2a
Upgraded detector
New capabilities
6/28/02 3
CDF CDF B Physics Goals
• Measurement of CP Violation– B0→J/ψKs sin(2β)– B0→ππ sin(2α)– Bs →DsK sin(2γ)
• Bs mixing measurement– Δms |Vtd|/|Vts|
• Radiative B decays– B→K*γ, Bs →φγ, Λb →Λγ
• Rare B decays– B0→µµ
• Lifetimes, masses, BR’s– Bs , Bc , Λb (unique to Tevatron)
• b production
6/28/02 4
CDF Ingredients for a B Measurement
• e.g. Δms from Bs→Dsπ
• N depends on Luminosity Trigger cross section Reconstruction efficiency
• S+B/S Reconstructed mass resolution
• εD2 Flavor taggingTagging efficiency ε Dilution D = 1-2w (w is mistag rate)Particle id
• σt proper time resolutionvertex resolution σLxymomentum resolution σPt (negligible)
• limiting factor for Bs→Dslν mode
2( m )22
1 1 S B( x )
N D Ss t
s e
Flavor Tag B0J/Ks
Run I/ RunII
BsDs
Run I/ RunII
SameSide π/K 2.1 / 2.0 % 1.0 / 4.2%
SoftLepton 2.2 / 2.2 % 1.7 / 1.7 %
Jet Charge 2.2 / 3.0 % 3.0 / 3.0 %
Opp.Side K - / 2.4 % - / 2.4%
Total εD2 6.3 / 9.6 % 5.7 / 11.3 %
6/28/02 5
CDF Tevatron Upgrade
• Upgrade for higher Luminosity– Tevatron Run I
• 6x6 bunches with 3.5µs bunch spacing
– Tevatron Run II• 36x36 bunches with 396ns spacing
– Further upgrade to 132ns
– (fewer interactions per crossing)
– Main Ring replaced by Main Injector
– Recycler
– pbar source upgrade
6/28/02 6
CDF CDF Detector Upgrade
Components from Run 1Central and extension muon systemCentral & wall calorimetersSolenoid
New for Run 2Silicon tracker (more coverage, z measurements )Central tracker (shorter drift time, improved stereo)Time of flight (All New!)End plug calorimeter (complete replacement)Central muon detector (Gaps filled in)Forward muon detectors (1 < |η| < 2)Luminosity Monitor Front end electronics (Run 1 bunch spacing 3.5µs,
Run 2 spacing 396/132ns)Trigger (Higher rates, tracking at L1, svt tracks at
L2)Software (Fortran → C++/Java)
6/28/02 7
CDF Silicon
Layer 00 1 r-phi layer 1.4 cm from beamline
Fully integrated with DAQ
Improves impact parameter resolution
SVXII87 cm length (covers luminous region)
5 r-phi layers 3 r-z, 2 r-1.2° stereo
Used for SVT trigger
Intermediate Silicon Layer (ISL)r-phi and r-1.2° stereo all layers
1 layer |η| <1, 2 layers | η| <2
Gives tracks at higher eta
Cooling problems have limited use
but is being fixed
6/28/02 8
CDF Central Tracker
• COT – 8 superlayers (4 axial, 4 2° stereo)– 12 measurements/superlayer, 30K channels– Smaller cell size than Run 1 tracker
• needed for 132ns beam crossing period– Readout with Multi-hit TDCs– dE/dx encoded in pulse width
– Hit resolution ~ 175µm
COT working very well
6/28/02 9
CDF Tracking Performance
COT: 99.7% single track efficiencyCOT+SVXII tracks:
Preliminary resolutions:σd0 ≈ 23µmσLxy ≈ 60µm
includes beam spot resolution of ≈ 35µm
Still can improve alignments Numbers don’t include L00
Calibration of E-loss and B fieldUse J/ψ mass for calibration
Cross checked with other particles
Energy loss correction depends on material 0.56 g/cm2 layer added to detector descriptionB field scaled by 0.13%
dEdx measurement from COT hits
Eloss+BfieldImproved ElossE-loss default
No E-loss
6/28/02 10
CDF Time of Flight
• Detector– 216 scintillator bars
• 2.8 m length
• 4x4 cm^2 cross section
– Coverage to |η| < 1
• PerformanceGoal of 100 ps time resolution gives
2 σ K/π separation for p<1.6 GeV/c
2 σ K/p separation for p<2.7 GeV/c
2 σ π/p separation for p<3.2 GeV/c
Preliminary Calibration
σ 110 ps
6/28/02 11
CDF Time of Flight (cont)
φ→KK reconstructionUsing generic sample of tracks
6/28/02 12
CDF Calorimeter
• Detector– Scint+Pb/Fe Towers with
EM/Hadronic sections• Covers 15° in phi, 0.11 in η
– 2-d strip/wire chamber at EM shower max
• In Central region
• Crucial for low energy electrons in trigger and analysis
• Performance– Fully commissioned
– Used for trigger and analysis
– Energy scale calibrated to ~1%
6/28/02 13
CDF Muon Detectors
• Central & Extension Muon Detectors– System commissioned and aligned– 95% live– Triggering on muon track stubs
• Forward Muon Detectors (New)– System commissioned– 98% live– Alignment underway– Will be added to trigger
6/28/02 14
CDF DAQ and Trigger
• L1 Trigger – Calorimeter towers (Em and Hadronic Et)– SumEt, Missing Et– Muons– Tracks
• Pt> 1.5 GeV. Matching for e, µ selection
• L2 Trigger – Calorimeter clusters (plus isolation)– Track matched to Shower Max (electron id)– SVT tracks -> displaced tracks select b,
charm– Processors calculate Lxy, (transverse) mass
• L3 Trigger – Farm of 240 dual processor PC’s– All data available for making decision – Uses full reconstruction (offline code) 50 Hz
~20MB/s
300-500 Hz
45 kHz
6/28/02 15
CDF Physics Goals and the Trigger
B and Charm Physics– SVT tracks: Hadronic Bs, B→ππ, Charm
• Displaced impact parameter, 2-D vertex, Lxy cut– Lepton + SVT: Semileptonic B, Radiative B– Dileptons: B→J/ψX
• QCD – Jets– Diffractive triggers
• Top– High Et lepton: W→lν– All Hadronic: ttbar→ 6 jets
• Higgs– High Et lepton: HW production– B-tagging (d0 cut) for H→bbar– H→ττ
• Exotics– High Et photons– Missing Et– Tau’s (cluster+ isolated track)– B-tagging
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6/28/02 16
CDF Silicon Vertex Trigger (SVT)
• Silicon based tracking at L2– New capability at hadron collider
• SVX readout on L1A– SVX chip digitizes and stores every 132 ns– Fast parallel readout over optical fiber
• Track roads seeded by L1 XFT tracks• Lookup tables match to pattern of hits
– Finds tracks with pt > 2 GeV– Currently match to 4 layers– Will change pattern to 4/5
• Track fit gives d0, curvature, phi0, χ2– σd0 ≈35µm, σc ≈6x10-6 cm-1 σphi0 ≈1mrad – Correction required for beam offset
• Beam spot measurement fed back to Tevatron to control beam position
– Information available but not yet used
6/28/02 17
CDF Hadronic B Trigger
• Physics goals– B→ππ, Bs →KK : CKM angle γ
– Bs →Dsπ, Ds πππ : Bs mixing• Ds→φπ,K*K, KsK
– Charm BR’s, masses
• Selection– L1: 2 opposite charge tracks, Pt >
2GeV, Δφ cut, • dominates L1A bandwidth
– L2: 2 svt tracks d0 > 100µm, Lxy cut
– Yield for B events lower than expected• Will improve with SVX fixes and more
efficient track patterns in SVT
Lxy
Beam spot
secondary vertex
R
PT
6/28/02 18
CDF Lepton + SVT Track Trigger
Physics goalsSemileptonic B decays
B cross sectionFragmentation fractionLife time, B+/B0
Bs and b (Bc)Bs mixing (need ~ fb-1)
Radiative B decays b→sγ (γ→ee)Sample for flavor tagging studies
Selection 4 GeV e, + 2 GeV SVT track
Run I single 8 GeV e, Lower B Et threshold
Run1 10 GeV vs Run2 6 GeV
~ 3 x SVT x Run I yieldRadiative decays
Large Run II inner materialX2.5 gain in acceptance~10 Bd ->K* γ / 100 pb-1~few Bs-> φγ / 100 pb-1
Lepton + D yield D0 D* Ds
Run I /100 pb-1 1800 230 60
Run II /7pb-1 350 120 30
Run II / Run I 2.7 7.5 7.0
6/28/02 19
CDF Di-lepton Trigger
• Physics Goals– B→ J/ψX
• sin(2β), lifetimes
– rare decays B→ll(X)
• Selection– 1.5 GeV dimuon
– 2 GeV dielectron
– 2-3X Run I yield• Run I: 2 GeV muon, 5 GeV electron
6/28/02 20
CDF Charm Physics
6/28/02 21
CDF Charm Yields
• Hadronic trigger gives large charm sample
Large percentage of D’s from direct production
With 2 fb-1 expect 10-100x samples of charm from Fixed Target experiments
Decay Mode Yield 50pb-1
D0→Kπ 300K
D0→KK 20K
D0→ ππ 10K
D+→Kππ 200K
Ds→KKπ 10K
D*+→ D0π D0→Kπ 80K
Λc →pKπ 300
6/28/02 22
CDF Charm Measurements
• Physics Prospects– Production cross sections
• for D0, D+, D*+, Ds, Λc
• can separate prompt from direct production
– Mass measurements
• mDs - mD+ , for Ds, D+ →φπ
– D0– D0 mixing search
– CP Violation searches
– Rare/Forbidden Decays
T
d
dP
6/28/02 23
CDF B Physics Prospects
• Collecting large sample of J/ψ, hadronic and semileptonic b decays
(Quoted errors below assume 2fb-1)
• Broad program of measurements– Lifetimes
• Measure cτ with error of .01 ps B0 ,B+; .03 ps Bs ; .04ps Λb
– b production – Δmd mixing measurement– b hadron masses– Branching ratios– Rare Decays
• Bs ,Bc , Λb measurements unique to Tevatron
J/ψ→µµ Sample
6/28/02 24
CDF B Prospects (cont)
• Bs mixing– All pieces necessary for measurement
are working• TOF, Hadronic trigger, SVX, L00
– Hadronic yields lower than expected• Working on improving trigger and
reconstruction efficiency
• sin(2β) from B→ J/ψKs
– will collect large sample of events• Use J/ψ→µµ and ee modes
– next step to optimize flavor tags– with 2fb-1 will have competitive
measurement• σ sin(2β) ≈ 0.06
6/28/02 25
CDF B Prospects (cont)
• Bs lifetime difference ΔΓs
– Use Bs→J/ψφ mode
– Fit lifetime and transversity angle of decay
• Separates CP even/odd states
– Error on ΔΓs/Γ of 0.05-0.08
• CP asymmetry in B0→ππ – Hadronic trigger collecting B0→hh
sample
– Use PID to separate B→Kπ , B→KK
– Error on asymmetry of 0.09
• γ from Bd→ππ , Bs→KK– Difference in asymmetries only from
CKM phases γ and β• Assume SU(3) symmetry
– Uses simultaneous fit of time dependent asymmetry
– Expect σγ ≈ 10°• Requires measurement of β
• Search for CP violation in Bs→J/ψφ – Asymmetry very small in Standard
Model• Test for new physics
– Error on asymmetry of 0.1 to 0.2• (depending on value of xs)
6/28/02 26
CDF Summary
• The CDF detector is working well and collecting data for physics
• Hadronic trigger greatly extends B and Charm Physics capabilities
• CDF will collect a very large Charm sample– Expect first charm measurements later this summer
– Broad charm physics program for Run 2
• B physics program has all the pieces in place– B triggers collecting samples
– Detector providing good reconstruction
– Particle ID working for flavor tagging
• Lots of interesting B measurements to come