First Heavy Flavor Results Using the Silicon Vertex Trigger

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First Heavy Flavor Results Using the
Silicon Vertex Trigger

• A. Cerri

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The SiliconVertexTrigger
20?s !!!
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The TwoTrackTriggeris just a selection based on
the SiliconVertexTrigger...

• Why so much emphasis on tracking at trigger
  level?
• B physics at hadron colliders has two main
  features
• Large cross section O(0.1 mb !!!)
• Huge background O(0.05 b !!!)
• So far CDF has only one cure require leptons
• There comes the challenge tracking at
  trigger level with sufficient resolution!

The TTT is the first case in which CDF
investigates low Pt B physics without explicitly
requiring leptons
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First HF signals...

• Offline confirmation of TTT cuts
• ?z(K-?) lt 5cm
• Lxy(D) gt 500 um
• d0(K)d0(?) ? 0
• PT(D) gt 5.5 GeV/c

• Offline confirmation of TTT cuts
• ?z(K- ?1, K- ?2, ?1-?2) lt 5cm
• Lxy(D) gt 800 um
• ?2xylt30
• PT(D) gt 6 GeV/c

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something even cleaner

• Offline confirmation of TTT cuts
• ?z(K- ?, K-?s, ?-?s) lt 4cm
• m(D0)?1.56,2.16 MeV
• Q(K)Q(?)lt0 Q(K)Q(?s)lt0
• ?R(D0-?s)lt0.2

m(D0)-m(D0 PDG)?0.25,0.3 GeV
m(D0)-m(D0 PDG)lt0.1
m(D)-m(D0)-0.1455lt3 MeV
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Is the Tevatron/CDF a charm factory?!??

• Get a clean charm sample
• d0(D) distributed differently for prompt/non
  prompt
• Careful modeling exploiting K0 and analytic models

FB16.4?0.7(stat)
There's Plenty of Prompt Charm!
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CP eigenstates...
With a selection very close to the K? signal we
see D0 decays to CP eigenstates, with incredible
yields!
are already accessible with good statistical
accuracy and reasonable systematics!!!
?(D0???)/?(D0?K?) ?(D0?KK)/?(D0?K?)
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KK/??/K? relative BR

• Is a good benchmark
• PDG measurements have errors close compared to
  our current statistics
• Systematics is reasonable because K?/??/KK share
• Selection
• ?Kinematics
• Mass

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And something strange !

• Offline confirmation of TTT cuts
• ?z(K-K) lt 4cm
• m(?)?1010,1035 MeV
• ?z(?-?) lt 4cm
• ?2(r?)lt7
• Lxy(D) gt 500 um
• helicity cut ?cos(??helicity)?gt0.4
• keep candidate with largest helicity
• Fit gaussianslinear background

• 1350?60 events
• 7.1?0.4 MeV/c2
• S/B?0.76

Yum

• 2360?70 events
• 8.4?0.2 MeV/c2
• S/B?1.4

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?m(D-Ds)
Systematics

• Is a good benchmark
• PDG measurements have errors close compared to
  our statistics
• Systematics is reasonable because D/Ds share
• Selection
• Kinematics
• ?Mass

Previous PDG average 99.2?0.5 MeV/c2
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What about Bees? (I)

• Offline confirmation of TTT cuts
• M(D0) within 4?
• ?z(tracks) lt 5 cm
• 0ltLxy(D)lt4 mm
• ??(D-?) lt 2 rad
• d(?)d(D) lt 0
• d(B)lt100?m
• Pt(B)gt5.5 GeV

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What about Bees? (II)

• Offline confirmation of TTT cuts
• Lxy gt 0.05
• eta(B) lt 1
• d(?) gt 0.02
• d(B) lt 0.075
• Isolation gt 0.5

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Comments on Yields

• Signals based on ?10pb-1 out of 2fb-1 to come...
• The data sample comes from commissioning with
• partial Si coverage
• Non optimized trigger
• Reliably understand these differences in
  simulation
• Expect ?x3 improvement in TTT B physics yields
• Additional improvements in offline efficiency
  expected

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Conclusions...

• Plenty of Charm!
• Good benchmark for two body charmless B decays
• Energy scale, PID and dE/dx
• By themselves
• Large statistics world class charm physics
• ?m(Ds-D)
• ??(D0???), ?(D0?KK) / ?(D0?K?)
• These are good physics benchmarks of what we will
  be able to do with the full statistics!
• Charmed/uncharmed B are showing up!
• First observation of fully hadronic B (hh, D0?,
  ?K)
• Background rates compatible with predictions
• Yields fully understood
• Now the fun begins!!!

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Backup Slides
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CDF II

• Renewed detector Accelerator chain
• Higher Luminosity higher event rate
• Detector changes/improvements
• DAQ redesign
• Improved performance
• Detector Coverage
• Tracking Quality

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Two Paths...
PiPi
DsPi
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How does it look like?
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Prompt fractions...
16.4?0.7(stat)
11.4?1.4(stat)
11.3?0.5(stat)
34.8?2.8(stat)
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Backup slide IHow well do we know how to model
the trigger selection/detector effects?
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Backup Slide IID-Ds cuts