Current and Anticipated Results in Bottom and Charm Physics from the Tevatron

1
Current and Anticipated Results in Bottom and
Charm Physics from the Tevatron

• Jonathan Lewis
• Fermilab
• Aspen Winter Conference
• January 2003

2
B Program Complement to ee- Factories

• Bs
• Flavor oscillations
• CP Violation
• Fits combining Bs?hh- and Bd?hh-
• New physics in Bs0 ? J/? f
• Mass, lifetime
• Bc
• Mass, lifetime, production, resonances(?)

• b Baryons ?b, ?b
• Mass, lifetime
• CP Violation
• ?b ? pp- vs. ?b ? pp
• B and D rare decays
• No tagging penalty!
• QCD
• B and D production in pp collisions
• Quarkonium

• Todays Talk Where we are on road to the
  Physics
• Results from Summer 2002

3
Run 1 The Foundation

• B triggers required leptons in the final state
  trigger
• Semileptonic channel highlights
• B0B0 Mixing, Production, Lifetimes

Dm 0.47 0.07 ps-1
4
Run 1 b J/y

• Rich and pure channel
• Highlights Lifetimes, production, Bc, first hint
  of CP

B0 J/y KS0
CDF Run 1

• Yesterdays sensation is todays calibration

5
Run 2 Revolution

• Higher Energy
• Higher Luminosity
• Higher Bandwidth
• Precision Tracking
• CDF New 96-layer drift chamber, 7-layer silicon
  barrel
• D0 2T solenoidal field, 8-layer fiber tracker,
  silicon barrel and forward disks
• CDF Time-of-flight detector for Kaon ID
• Displaced Track Triggers for all-hadronic
  channels
• What was offline analysis has moved to Level 2
  trigger

6
B Physics for Dummies The 3 Rs

• Rate
• Cross section
• Luminosity
• Trigger
• Recognition
• Tagging
• Reconstruction
• Extract the signal
• Minimize the background

7
R 1

• Rate

8
Cross Section

• B physics enabled by large cross section
• s(b)10mb for pTgt5 GeV, ?lt1
• 1000 B per second at design luminosity
• Compare to 10 B per second at ?(4S) factories
• Run 1 total cross section factor 2 above NLO
  predictions
• Ös1800 GeV
• Effect seen over many channels
• Energy dependence (630 vs. 1800 GeV) agrees with
  QCD

9
Theoretical Improvements

• Recent work on the non-perturbative physics

• Fragmentation functions from NRQCD-inspired fits
  to LEP data (names)

• Resummation of next-to-leading logs and retuning
  of Petersen fragmentation (e0.002)

Kniehl, Kramer hep-ph/9901348
Cacciari, Nason hep-ph/0204025

• Looking forward to marriage of matrix-element and
  parton-shower Monte Carlos

10
Cross Section Run 2

• First D0 measurement
• Muon Jet
• Ös1960 GeV
• b content from PT,rel
• Lepton momentum
  
  perpendicular to jet direction
• Expectations for Run 2
• Precision tests of perturbative region (pT2mb2)
  with large data samples
• Detailed exploration of non-perturbative region
• ds/dpT (b J/y) down to pT(b)0

11
Luminosity

• Tevatron performance thus far below expectations
• Getting better
• Record luminosity 3.61031cm-2s-1
• Best week 7pb-1

• CDF
• 80 pb-1 good runs
• Excludes studies, commissioning
• 65 pb-1 with silicon
• Typical efficiency for December 80

Start of CDF physics data
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Trigger

• Electrons ET,PTgt2 GeV
• Muons PTgt1.5 GeV
• Tracks PTgt1.5 GeV
• Displaced tracks
• Typically require d0gt100mm, PTgt2 GeV
• CDF SVT resolution 50mm
• Includes 30mm rms beam width
• Differences
• CDF pipelined Level 1 allows hadronic B decay
  trigger
• D0 has hlt2 low-pT lepton coverage

13
Hadronic Trigger

• Nominal cuts
• pTgt 2 GeV
• pT1pT2gt5.5 GeV
• Opposite Charge
• Opening Angle
• 2ºltDflt90º for bc
• 20ºltDflt135º for pp
• d0gt100mm

• Loose cuts (b c only)
• pTgt 2 GeV
• 2ºlt Dflt90º
• d0gt100mm
• Automatically updating prescale

14
R 2

• Recognition
• (Tagging)

15
Whats new (and old)

• Tagging plans follow from CDF Run 1 results
• Leptons and jet-charge with greater coverage
• Same-side tag
• New Element Time-of-flight for CDF
• ID Kaons for PT lt 1.6 GeV
• 120 ps resolution

f ?KK-
16
Expected Tagging Performance

• Both Experiments relying on forward tracking and
  large lepton coverage

17
R 3

• Reconstruction
• (and results!)

18
Physics Goals With Two Leptons

• CPV in B0 ? J/? KS0
• Yesterdays sensation is todays calibration
• Anomalous CPV in Bs0 ? J/? f
• B0 ?µµK()
• ?b?J/? ? Lifetime, production, CPV, etc.
• Bc ? J/? p, J/? l?
• Quarkonium production

19
D0 on the Road to Physics

• Good Resolution from new tracker
• J/? ? µµ-

Muon plus central tracking
Muon stand alone system
20
D0 Tracking Neutral Vees

• KS0 ? p p-

• ?0 ? pp

21
D0 First Exclusive B Decays
B ? J/? K

• 5pb-1
• Sample of 3000 J/?
• Outer muon trigger
• pT(µ) gt 2 GeV
• pT(K) gt 0.5 GeV
• pT(B) gt 10 GeV
• Vertex fit ?2 gt10
• Lxy gt120 µm

22
D0 First Physics

• Inclusive b ? J/?X Lifetime
• 416 30 signal events
• 2184 47 prompt J/?s
• ?(B) 492 37 ?m (stat. error only)
• Compare to PDG ?(B) 469 ?m

• J/? Cross Section
• 5pb-1
• Large rapidity coverage

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CDF Results B Meson Masses
Bs0 ? J/? F 5360.3 3.8 2.9
B ? J/? K 5280.6 1.7 1.1
2.1

• 18 pb-1, incomplete silicon coverage
• Bs uncertainties already close to Run 1
• Systematics will be greatly reduced with more
  data and recent track reconstruction improvements

B0 ? J/? K0 5279.8 1.9 1.4
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CDF Results B ? J/? K Lifetime

• 18 pb-1
• Incomplete Silicon Coverage
• 154 15 Events
• t 1.49 0.14 (stat.) 0.04 (sys.)
• Compare
• Run 1 1.68 0.07 0.02
• PDG 1.674 0.018

• Expectation
• Systematics to be greatly reduced with more data

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All Hadronic Modes b?c

• Primary goal Bs-Bs favor oscillations
• a.k.a. Mixing
• Measure frequency ?ms
• ?ms /?md yields Vts/Vtd
  up to 5 theoretical
  
  uncertainty
• Important constraint
  on CKM
• Much more physics along the way and beyond
• Masses
• Lifetimes
• Other CP violation studies

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Before b comes c

• Hadronic trigger yields large charm samples
• Both direct and from b decays
• Significant measurements at hand quickly for
  charm production and decay properties
• D-Ds Mass Splitting
• Decay mode fp , f ?KK-
• ?m 99.280.430.27 MeV
• PDG 99.20.5 MeV
• Systematics dominated by
  fit model and selections
  
• Can be reduced with
  more data

27
D0 ?hh- Decays

• Measure Cabibbo-suppressed branching ratios
• Requires detailed modelling of detector
  performance
• No particle ID
• Account for both hypotheses for Kp mode
• 10 pb-1 sample
• Systematics dominated by background and
  acceptance models

K-p
KK-
K-pp0
pp-
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Branching Ratio Results

• G(D?KK)/ G(D?Kp) (11.170.480.98)
• PDG (10.830.27)

• G(D? pp)/ G(D? Kp) (3.370.200.16)
• PDG (3.760.17)

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Charm Production

• Displaced track trigger sensitive to long lived D
  mesons
• Prompt production much greater than from B
• Can differentiate based on lifetime and impact
  parameter (d0)

Prompt D
D from B
Significant impact parameter
Long apparent lifetime

• Efficiency sculpted by trigger cuts

OK
Excluded
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Prompt Charm Fraction

• Prompt fraction from d0 distribution
• Resolution function from simulation
• Check in KS ? pp sample

• B fraction in several D meson channels
• D0?K? 16-24
• D??D0 11-20
• D??K?? 11-17
• Ds??? 32-40

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Charmless B Decays

• Extract CP violation from multiple modes
• Bd?pp
• Bd?Kp
• Bs?Kp
• Bs?KK
• Separate Penguin and Tree amplitudes

• First signal

d
u
u
b
d
d

• 31 Signal-to-noise
• Rates understood
• Consistent with expectations after correction for
  acceptance

d
b
u
g
u
d
d
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Sensitivity for ?

• Separate modes on a statistical basis using mass
  shapes and dE/dx
• Sensitivity depends on strong-interaction phase
  between tree and penguin processes
• For 2 fb-1 expect d?5-10

• Bd?pp
• Bd?Kp
• Bs?Kp
• Bs?KK

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Bs Mixing

• First All-Hadronic Decays
• B- ?D0p-, D0 ?K-p

Mixing 5s Discovery Sensitivity

SN 12 11 21
5612 Events
Excluded
Event Yield
34
Outlook

• CDF
• 4 out-of 5 majority logic for SVT tested this
  month
• Expect 50 efficiency improvement
• Hoping to run DAQ at higher rates and increase
  cross section of B events to tape
• Level 1 12 kHz ? 25 kHz
• D0
• Track trigger commissioning complete this winter
• Fiber and silicon
• Hoping to improve trigger bandwidth
• Level 1 now 1 kHz, want 4 kHz
• Tevatron
• 100 pb-1 more by summer

35
Conclusions

• CDF and D0 detectors and reconstruction
  performing well
• First B signals seen
• Lots of work to do
• Exciting results just around the corner