CDF CDF Status and Prospects Stephen Miller University of Michigan 5 th International Conference on Hyperons, Charm and Beauty Hadrons June 28, 2002
Jan 19, 2016
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