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Charm, B, and QCD Physics in CDF
Masashi Tanaka (Argonne)
for the CDF Collaboration
Fermilab Wine and Cheese Seminar
March 28th, 2003
1
Outline
•Introduction
•QCD Physics
– Inclusive Jet cross section
– Dijet mass distribution •Bottom Physics
– Jet shape and energy flow – Lifetime: B0, B+, Bs g J/yX
– Diffractive dijet production – Semileptonic B decays
– Two body Bghh decays
– Study of hadronic B decays
•Charm Physics
– J/y production cross section
– Charm cross section
– Mass: Ds and D+ •Summary
– Cabbibo suppressed D0 decay
– Rare Decay: D0gmm
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 2
Integrated Luminosity
Jan 03
Data used for Today’s results
Mar 02 – Jan 03
130 pb-1 (delivered)
100 pb-1 (to tape) Good Run
Jet physics: ~ 85 pb-1
Silicon is off
B/Charm: ~ 70 pb-1 (beam condition)
Mar 02
commissioning
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 3
CDF Detector Overview
New Central Tracker (COT)
ToF counter for K/p separation
Placed right before the Solenoid
New Plug Calorimeter
1.3 < |h| < 3.5 Muon Detector
More Coverage
SVX: Acceptance increase
|z0| < 30 g 45 cm
Forward Calorimeter L00: Vertex resolution
3.5 < |h| < 5.1 ISL: |h| < 2.0
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 4
CDF Trigger System Overview
• Crossing: 396 ns: 2.5 MHz
• Level 1: hardware
– Calorimeter, Muon, Track
– 15kHz (reduction ~x200)
• Level 2: hardware + CPU
– Cal cluster, Silicon track
– 300 Hz (reduction ~x5)
• Level 3: Linux PC farm
– ~ Offline quantities
– 50 Hz (reduction ~ x6)
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 5
Silicon Vertex Trigger (SVT)
•Level 2: Silicon Vertex Trigger •Increase physics sensitivity of
–Use silicon detector information the Run II CDF
•Good IP resolution – CDF as “Charm Factory”
•Trigger on displaced track •> Millions of D’s per 100 pb-1
– beamline reconstruction – Collect Hadronic B sample
•update every ~ 30 seconds •No Lepton required in final state
–IP resolution: ~ 50 mm •Bs physics (mixing in Dsp)
• 35mm beam size + 35mm SVT – Higgs/new particles decaying
heavy (b and c) quarks
f
z
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 6
QCD Physics Program in CDF
•Jet production
– Inclusive Jet gToday
– Dijet gToday •Tevatron is a Hadron Collider
– > 2 Jet – All interactions are
• Photon production fundamentally QCD!
• b-Jet production
• W/Z + Jet production •Understanding the QCD physics is
–Background for Top, Higgs.. indispensable for many analysis
•Underlying events gToday – Parton distribution function
•Jet Property – Underlying event
– Jet shape gToday – QCD process as background
– Jet substructure
– Jet clustering algorithm
•Diffractive processes gToday
•And many more….
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 7
Inclusive Jet Cross Section
Run I g Run II
1.8 TeV g 1.96 TeV
Theory predicts
x5@600GeV
x2 higher cross section
at Jet ET = 400 GeV
x5 higher cross section
at Jet ET = 600 GeV
x2@400GeV
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 8
Inclusive Jet Cross Section (Run I)
•Run I measurement •Compared with theory prediction
– Central Jet: 0.1 < |h| < 0.7 – NLO QCD + CTEQ3M
– Run IA and IB agree well – Excess at high energy
• Evidence of new physics ?
• Uncertainty of PDF?
(CDF Run I)
(CDF Run I)
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 9
Fits to the Run I CDF/D0 Data
•The excess can be explained by •Still have large uncertainty for
enhancing the gluon PDF high x gluons
•Include the CDF/D0 Jet cross – Good precision measurement
section for fitting the PDF of high ET Jet cross section may
– Extra weight for high ET is reduce the uncertainty
needed to fit the CDF/D0 data
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 10
The Run II Jet ET distribution
Highest ET Jet: ~600 GeV
(Run I: 400 GeV)
Jets
Event with the highest ET Jet
Two highest jets come from
the same event
ET= 607 GeV
h = 0.43
• 85 pb-1
• Measured ET distribution ET= 569 GeV
– Before unsmearing h = -0.19
• 4 datasets with different
–Trigger Jet ET thresholds
–Prescales
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 11
Inclusive Jet Cross section
•Jet Cross section can be • ~ 10 orders of magnitude
compared with theory after • Two high ET data points
–Calorimeter energy correction – Run I: ET < 400 GeV
–Resolution unsmearing
New in Run II
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 12
Comparison with Theory Prediction
•NLO QCD (CTEQ 6.1) •The dominant systematic
– Data and Theory agree uncertainty
within error – Jet energy scale (5%)
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 13
Dijet Mass Distribution
•Theory predicts Run II dijet cross •The distribution is not corrected
section is x10 higher than Run I for calorimeter resolution
at Mass = 1.4 TeV •A good place for new physics
•One candidate with M ~1.4 TeV search (last week’s seminar by
–The same event as the highest Eva. H) . No evidence of NP.
ET jet event
Mass = 1364 GeV
After Energy correction
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 14
Run II / Run I Cross Section Ratio
•Inclusive Jet cross section •Dijet mass distribution
-Theory predicts the Run II/Run I ratio with
small uncertainty (~ 10%)
- Data agrees with theory within error
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 15
Study of Jet Shapes Good agreement
in Central detector
•Measure differential Jet
Shape in the Calorimeter
•Compare with Pythia +
detector simulation
(r)
1 1 E (r r / 2)
T
r Njet E (0, R)
T
Slightly wider in forward region at Low ET
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 16
Study of Energy Flows
•Measure the energy flow
with the calorimeter
–Energy outside of Jet
–Probe the underlying
event
•Compare with Pythia
(tuned by using the CDF
minimum bias event)
Increasing Δηjet
Increasing ETjet
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 17
Diffractive Dijet Production
•Diffractive Process
Non Diffractive Single Diffractive Double Pomeron
Exchange
•Diffractive event signature:
– No energy deposition in the
forward detector
•Miniplug Calorimeter (MP)
•Beam Shower Counter (BSC)
– Directly detect the anti-proton
from the diffractive process
•Roman Pot (RP)
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 18
Single Diffraction
•Hits in the Roman Pot
– anti-proton: diffraction
• x: fraction of momentum loss of
anti-proton
–Measured with calorimeter
•xBj: fraction of anti-proton
momentum carried by hard
scattering parton
RP
1-x
anti-proton
Jet1
xBj
Jet2
proton
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 19
Double Pomeron Exchange
•Dedicated trigger for DPE:
– No significant energy in east
side Miniplug and Beam shower
counter DPE
• Proton: diffraction
SD
– Hits in the Roman pot detector
•Anti-proton: diffraction
–Two low ET jets
•Collect ~ 15K of DPE candidate
events (~100 events in Run I)
•Compare several kinematic
quantities between SD and DPE
– Average h of two jets
– opening angle of two jets
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 20
Bottom and Charm Physics in CDF
•Studies of QCD •Studies of CKM mechanism
– Onium Production (y,U) –Mixing
• Cross section • D0: D*gD0p
• Polarization • B0 (|Vtd|) : B0gJ/yK*0, B0glnD
– Charm production • Bs (|Vts|) : BsgDsnp, lnDs, …
• Cross section – Gs: BsgJ/yf, J/yh, lnDs, DsDs
• D** Production –CP violation
– Bottom Production • b: B0gJ/yK0s
• B Cross section • a: B0gpp
• Fragmentation • g: BgDK, BsgDsK
• g: B0, Bs g Kp,pp,KK
•Mass and Lifetime
• Exotic: BsgJ/yf , D0gKK,pp
– D0, D+, Ds, Lc, …
– B0, B+, Bs, Lb, Bc, …
Study of Bs,Lb,Bc,
Today’s Topics:
•Rare Decays Is unique at Many of the analyses are still
– B g ll, llK, … hadron collider in progress and we show only
– D g ll, llp, … status and prospects
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 21
CDF Trigger for B/Charm Physics
• (1) Dimuon dataset:
•CDF has three dedicated triggers – 2 central muons pT > 1.5 GeV
for B/Charm physics • Run I : > 2 GeV
–Trigger on J/ygmm decays
•(1) Dimuon • Collect ~ 70 pb-1
–J/ygmm – ~ 0.5M J/ygmm signals
• (2) Lepton + track
–Semileptonic decays
• (3) Two track
–Hadronic decays
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 22
CDF Trigger for B/Charm Physics
•(2) Lepton + Track •(3) Two Track Trigger
– 1 muon/electron pT> 4 GeV – 2 Tracks with
– 1 other track with •pT>2GeV
• pT > 2 GeV, SVT IP > 120 mm •SVT IP > 120 mm
–M(l-Track) < 5 GeV – pT1+pT2 > 5.5 GeV
•Collect ~70 pb-1 of data •Collect ~70 pb-1 of Data
– ~ 0.5M B g lX signal – ~ 0.5M D0gKp signal
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 23
J/y Production Cross Section
•Run I Measurement: CDF Run I
– LO calculation: 1/ 100 x CDF
•Non-relativistic QCD
– Include color octet states
– Theory doesn’t predict the
absolute normalization
•Fitting the CDF data
•Prediction
– J/y production is dominated by
the color octet mechanism
– J/y is polarized at high pT
•Some discrepancy (~ 2s)
between the Run I polarization
Transverse
polarized
measurement and NRQCD
– Awaiting Run II measurement
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 24
J/y g mm Cross Section
•1.5x2 = 3 < M(J/y) – 2xM(m) •Dimuon Mass distribution for the
– Trigger on stopped J/y lowest pT bin (0-250 MeV)
•We can measure cross section
down to pT = 0
– s(ppgJ/y; pT>0; |h|<0.6)
– s(ppgbbgJ/y; pT>0; |h|<0.6)
Background is subtracted
Cross section measurement is in progress
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 25
Production Cross Section: Charm
•Run I Measurement: •Run II
– D* g D0p: D0gmnKX – Use two track trigger sample
•muon with pT > 8 GeV – Early Run II data (~6 pb-1)
–Slightly higher than theory •enough statistics for counting
expectation experiment
– D0, D+, D*+, Ds
CDF Run I (unpublished)
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 26
Production Cross Section: Charm
•For measuring the Charm cross
section, we need to separate
direct D and BgD decays
– Use Impact parameter of D
– D meson from B decay has
larger impact parameter
•Direct Charm fraction
– D0: 86.6 0.4 3.5 %
– D*+: 88.1 1.1 3.9 %
K
– D+: 89.1 0.4 2.8 %
– Ds+: 77.3 3.8 2.1 %
D p
P.V. B
• Cross section measurement is in
progress X
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 27
Mass: Ds – D+
•Ds, D+ g fp ; f gKK •Momentum scale of the tracking
– Same final state, almost detector is calibrated using the
J/ygmm
identical kinematics
– 10 pb-1 of two track trigger
•Measure mass difference + Magnetic field correction
– Systematics are reduced
+ Energy loss correction
(dE/dx in the tracking detector)
Before correction
•Then extensively tested using
M Ksgpp, D0gKp, Ugmm, …
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 28
Ds – D+ Mass Difference
•It’s our first Run II Paper!! •Results: M(Ds) – M(D+)
– 99.41 + 0.38 + 0.21 MeV/c2
– (PDG: 99.2+0.5 MeV/c2)
It’s CDF control room A typical place where CDF
(We can’t analyze data here!) physics is being produced
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 29
D* tagging
•Very high purity D0 signal using •Eliminate the “reflection”
“D* tag” technique background (D0gKp and pK)
–D*+gD0p: Q =39 MeV •Initial flavor of D0 is known
–M(D*)–M(D0): – D*+ g D0 + p+ / D*- g D0 + p-
• s(MD) ~ 10 MeV – The best place to study D0
• s(M) ~ 0.6 MeV mixing and CP violation
– 20% of the D0 : D*+ tagged
with D* tag
W/o D* tag
s~0.6 MeV
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 30
Cabibbo Suppressed D0 Decays
s d
Vus u W u
W Vcd
c s c d
u u u u
•Summer 2002 (10 pb-1): no D* tagging
– Br(D0gKK)/Br(D0gKp)=(11.17+0.48+0.98)%
– Br(D0gpp)/Br(D0gKp) = (3.37+0.20+0.16)%
– main systematics: background subtraction
•Spring 2003 (65 pb-1): with D* tagging
– Repeat the Br measurement
– Direct CP asymmetry in pp and KK decay
– Results expected soon
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 31
Rare Decay Search: D0 g mm
•D0 g mm
– SM expectation : ~ 10-13
– Enhancement by new physics
• R-parity violating SUSY: ~ 10-6
– Current best limit
•< 4.1x10-6 (90% CL)
– E777, Beatrice
•Analysis Muon detector fiducial
–Use D* tagged D0
–Use D0gpp signal for
normalization mode
•Almost identical kinematics
–Br(D0gpp) ~ 1.5x10-3
•300 D0gpp g ~1 D0gmm signal
(Br=4.1x10-6)
–D0gpp is one of the major
sources of background as well
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 32
Rare Decay Search: D0 g mm
•Background (1) •Background (2)
–D0gpp with both pgm fake –Combinatorial background
–Nbg = N(pp) x prob(fake) 2 –Linear extrapolation of the high
– fake prob. Is measured in mass sideband events
D0gKp signal
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 33
Rare Decay Search: D0 g mm
•Expected background after the
optimized selection cuts
– 1.7+0.7 events
•Fake: 0.22+0.02
•Combinatorial: 1.5+0.7
• 0 events in search window
•New best limit
– Br < 2.4 x 10-6 at 90% CL
– Br < 3.1 x 10-6 at 95% CL
•For future:
–Much higher integrated luminosity
•Need further background study
–D0g em, ee
–D+gmmp
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 34
Exclusive B g J/y mSignals m
m
K+ K+
K+ K-
B+ B0 p- Bs
m m
m
B0 gJ/y K*0 (gKp) Bs gJ/y f (gKK)
B+ gJ/y K+
~ 220 signal events ~75 signal events
~ 640 signal events
(>1000 events
Normalization mode Golden mode for
With loose selection)
for sin2b analysis Gs measurement
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 35
More BgJ/y signals
•B0gJ/yK0s • LbgJ/yL
–Golden mode for sin2b – Mass and Lifetime
– 220+18 signal events – 53+11 signal events
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 36
B Lifetime
•Heavy Quark Expansion (HQE)
predicts the lifetimes for different
B hadron species
– t(Bc) << t(Xb0) ~ t(Lb)
< t(B0) ~ t(Bs) < t(B-)
< t(Xb-) < t(Wb)
– t(B+)/t(B0) = 1.03-1.07
– t(Bs)/t(B0) = 1.00 + 0.01
– t(Lb)/t(B0) = 0.9-1.0 •B+/B0 and Bs/B0 measurements
agree with prediction
• Small discrepancy for Lb lifetimes
– LEP + CDF Run I
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 37
B0, B+ , and Bs Lifetimes
•Use exclusively reconstructed B
signals in J/ygmm dataset
– B+ gJ/y K+
– B0 gJ/y K* (K* g Kp)
– Bs g J/y f (f gKK)
– LbgJ/yL (Lgpp): in progress
•ct = LB / pBx MBPDG
•Simultaneous fitting to
–MB: Extract signal fraction
– ct: Extract the lifetime
MB,pB m-
LB
K+
B+
m+
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 38
B Lifetime Results
• Lifetime Results:
– B+ 1.57 + 0.07 + 0.02 ps
• PDG: 1.674+0.018 ps
– B0 1.42 + 0.07 + 0.02 ps
• PDG: 1.542+0.016 ps
– Bs 1.26 + 0.20 + 0.02 ps
–Measured lifetime depends on the
mixture of two CP states
• PDG: 1.461+0.057 (average)
•Lifetime Ratio results
– B+/B0 1.11 + 0.09
•PDG: 1.083+0.017
– Bs/B0 0.89 + 0.15
•PDG: 0.947+0.038
•Prospects
– Stat. error on lifetime will be
approximately scaled down by
• [ 70 pb-1 / L(Run2) ] –1/2
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 39
Semileptonic B g ln + D0, D+, D*
•Lepton + Track dataset (60 pb-1)
– BglD0X (D0gKp) : ~ 10K
– BglD*+X (D*gD0p): ~ 1.5K
– BglD+X (D+gKpp): ~ 5K
•Good signals for calibration
– Measure B+ and B0 lifetime
– Study B0-B0 mixing
Lepton
B D SVT track
n
P.V.
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 40
Semileptonic Bs and Lb Decays
•Bs g ln DsX (Dsgfp) • Lb g lnLcX (LcgpKp)
Lifetime: stat. ~ 0.07 ps Lifetime:stat. ~ 0.12 ps
(PDG:0.057 ps) (PDG:0.08 ps)
Future: Bs mixing (low ms case) Future: semileptonic form factor
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 41
Flavor Tagging
•B flavor tagging
–For reconstructed B, to identify
whether the B is generated as
the b or b (Mixing, CP violation)
–Tagging efficiency: e
–Dilution: D = 1 – 2w
–Effective tagging efficiency eD2
•Effective statistics:NsiggNsigeD2
Run II Projections in Tevatron YB
B0J/yKs BsDsp
SST 1.9% 4.2% (TOF)
SLT 1.7% 1.7%
JETQ 2.0% 3.0%
Kaon 2.4% 2.4%
Kaon
Total 9.0% 11.3%
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 42
Flavor Tagging
•Statistical uncertainty for tagging
efficiency
–A typical tagging: e=0.1,D=0.4,eD2=1.6%
–1000 events: eD2 =1.6+0.7% (44%) No charm contamination
–100K events: eD2=1.60+0.07% (4.4%)
•We can’t study/optimize the flavor
tagging with ~O(1000) events of the B
signal events
– B g J/yK: ~ 1000 events/100pb-1
– B g Dp: ~ 500 events/100pb-1
•Our solution: Use Semileptonic B
decays in the lepton + track dataset
– ~200K semileptonic B signal events
– High B purity
– Lepton Charge = Decay flavor of B
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 43
Bgh+h-
•Bgh+h- signal in the two track
trigger sample
– 301+27 signal events
– Good S/N ~ 1
•This signal is combination of
four decay channels
– Tree (Br~5x10-6)
•B0 g pp : Bs g Kp
– Penguin (Br ~1.5x10-5)
•B0 g Kp : Bs g KK
•We can separate these decays
– Decay kinematics
– COT dE/dx
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 44
Bgh+h-
•Kinematical Separation •dE/dx Separation
– a = (1 – p1/p2) q1
– M(pp)
M(pp) is Lorentz invariant
If it’s really Bgpp
Simulation
M(pp) is not Lorentz First results expected soon
Invariant for BgKp - Br(B0,Bs->KK,Kp,pp)
Simulation - Direct CP asymmetry in BgKp
~ 15% resolution for Acp
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 45
Hadronic B signals
•Two track trigger data (65 pb-1)
•Reconstruct hadronic B decays
– B0gD+p (D+gKpp): 413+40
– B+gJ/yK(J/ygll): 311+25
Normalization mode for
the other decays
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 46
Hadronic Bs and Lb Decays
•Bs g Ds p
– Golden mode for Bs mixing
•65 pb-1 of two track trigger data
– BsgDsp(Dsgfp) : 40+10 events
– BsgDs*p (Dsgfp) : 65+20 events
•More channels to be added
– Bs g Ds ppp
– Ds g K*K, K0sK, ppp
•Further optimization of trigger
strategy to obtain more signals
•Estimate the sensitivity for Bs mixing
–Flavor tagging, time resolution…
• Lb g Lcp (LcgpKp)
– ~ 40 events in 65 pb-1
•More channels to be added
– Lb g Lcppp, pD0p
– Lc g Lppp
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 47
Summary
•Run II CDF collected ~100 pb-1 of data
– ~85 pb-1 for Jet physics, ~70 pb-1 for B/Charm physics
•Many Interesting physics studies are being made
–1.8 TeVg 1.96 TeV: x5 higher Jet cross section at ET = 600 GeV
– New detector and trigger system:
•Forward detectors g Diffractive physics
•The SVT g Great success!
– CDF as Charm/B factory
– Unique at hadron collider
•We are working hard to understand the new detector and trigger systems
– Some of the systematic uncertainties are still large (conservative)
– They can be reduced in future
•We are preparing for high luminosity
– QCD: B jet cross section, W+Jet cross section,…
– Charm: D0 mixing, CP asymmetry, rare decays…
– Bottom: studies of Bs, Lb, Bc, CP violation, Bs mixing…
Fermilab W&C March 28, 2003 Masashi Tanaka (Argonne) 48
