B States at the Tevatron

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B States at the Tevatron
Matthew Jones Purdue University/CDF
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The Goals of Heavy Flavor Physics
Is the CKM matrix unitary? Is it the source of
CP violation seen in the Kaon system?
circa 1996
hep-ph/9612327
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The Goals of Heavy Flavor Physics
New

• New Physics
• Expect many new phases in quark couplings
• Should be manifest at some level in heavy
  flavor decays
• Could be used to probe details of flavor
  structure in new physics scenarios
• Will require determining heavy flavor matrix
  elements with great precision

Lattice QCD HQET
(and kin)
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hep-lat/0510113
Physical light quark masses
Physical heavy quark masses
Lattice QCD
HQET
ChPT
(small lattice spacing)
(large lattice volume)
NRQCD
Symanzik-improved staggered quarks
Gold plated processes At most one hadron in
initial and final state.
Particularly well suited for heavy hadron masses.
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• Orbitally excited B mesons
• New B-flavored baryons
• ?b lifetime
• Bc mass and lifetime

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P-Wave B Mesons
eg, Godfrey Isgur, Phys. Rev. D32, 132
(1985). Also, Falk and Mehen, Phys. Rev. D53, 231
(1996).
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P-Wave B Mesons
Using B ? J/?K
Published PRL 99, 172001 (2007)
overlaps with direct
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P-Wave B0s Mesons
Kaon ID dE/dx Time-of-Flight
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P-Wave B Mesons
Properties
Production Rates from DØ
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B-flavored Baryons
Isospin
Strangeness
Spin 1/2 ground state
Using fully reconstructed ?b decays
Excited spin 3/2 state
Using clean J/? signal
???
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Observation of Sb at CDF

• Analysis optimization

• Discriminating variables for
• pT(Sb)
• Pion impact parameter
• Angular information in decay

318060 ?b??cp- decays in 1 fb-1
Signal from Monte Carlo
Background from Q sidebands, away from expected
signal region.
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Observation of Sb at CDF

• Signal region chosen based on theoretical
  expectations (HQET)
• Dominant background from ?b with a random track.

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Observation of Sb at CDF

• Within 2 MeV of predicted splitting...

arXivhep-ph/0307243 arXivhep-ph/0611306
Published PRL 99, 202001 (2007)
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Observation of

• Challenge low pT, displaced track from

DØ dedicated track reconstruction algorithm
CDF dedicated tracking of ?- in silicon detector
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?b Observation
Published PRL 99, 052002 (2007)

• Prediction based on same technique as Sb-?b
  prediction
• Clean enough to consider lifetime measurements?

Published PRL 99, 052001 (2007)
(arXiv0706.2163)
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B-baryon Lifetimes

• Theory

• Experiment, ?b??cl-X

1.00
0.97
0.94
0.90
0.86
OPAL, 96
CDF, 96
ALEPH, 98
DELPHI, 99
DØ, 2007
Reaching agreement?
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New Measurements

• Theory

• Experiment, ?b?J/??

1.00
0.97
0.94
0.90
0.86
DØ, 2007
CDF, 2007
Most precise measurements to date
Maybe... maybe not...
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DØ Analysis of ?b?J/??

• 17120 ?b decays
• 71738 B0?J/? K0s

Consistent with PDG average.
Published Phys. Rev. Lett. 99, 142001 (2007).
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CDF Analysis of ?b?J/??
53838

• 3.2s higher than world average

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CDF Analysis of ?b?J/??

• Lifetimes in many other decay modes consistent
  with world averages
• No evidence for bias due to decay topology
• Some, but not all, systematic effects may be
  correlated with result from DØ.

• CDF and DØ results differ by only 2.3s...
• Precise, independent measurements would benefit
  both theory and experiment.

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CDF Exclusive decay

• Blind search, optimized using B?J/?K as proxy
  for B-c decay.
• Precise mass measurement
• Lattice prediction

hep-lat/0411027
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DØ Observation of
Preliminary February 22, 2008
DØ 1.3 fb-1
54 12 events
Now using 3D impact parameter significance Blind
search using B?J/?K as proxy for Bc Corrected
for observed mass biases, consistent with CDF
result.
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DØ Bc Lifetime

• Reconstruct J/??µµ-, add a third track
• Apply muon ID, pT and vertexing requirements
• Significant evidence for semileptonic Bc decays

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DØ Bc Lifetime

• Backgrounds constrained by M(J/?µ)
• Prediction from QCD sum rules

hep-ph/0308214

• Consistent with previous measurements.
• Most precise measurement to date.

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Summary from CDF and DØ

• New B states observed over the past year
• No surprises all were expected to exist
• Demonstrates the power of a hadron collider for
  heavy flavor physics
• B hadron lifetimes
• Continue to be quite interesting!
• Lifetimes of newly observed baryons possible, but
  challenging
• Bc increasingly well characterized

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Backup Material
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The Experiments

• 8x2 layer fiber tracker, ?lt2
• Muon coverage ?lt2
• Triggers 2 kHz Level 1 rate
• Single muon, pTgt 3 GeV
• Di-muon, pT gt 2 GeV

• 8x12 layer drift chamber, ?lt1
• Muon coverage ?lt1
• Triggers 20 kHz Level 1 rate
• Di-muon, pTgt1.5 GeV
• Displaced tracks

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Exclusive B Decays
23,300 B ? J/? K from 1.3 fb-1
51,500 B ? J/? K from 1.5 fb-1
(18,000 per fb-1)
(34,000 per fb-1)
s 40 MeV/c2
s 10 MeV/c2
... but superb rapidity coverage!