Transcript Document 7230504

Current and Anticipated Results in Bottom
and Charm Physics from the Tevatron
Jonathan Lewis
Fermilab
Aspen Winter Conference
January 2003
B Program: Complement to e+e- Factories

Bs




Flavor oscillations
CP Violation
 Fits combining
Bs→h+h- and Bd→h+h New physics in
Bs0 → J/ψ φ
Mass, lifetime
Bc



b Baryons: Λb, Ξb



B and D rare decays


No tagging penalty!
QCD

Mass, lifetime, production,
resonances(?)
Mass, lifetime
CP Violation
 Λb → pπ- vs. Λb → pπ+

B and D production in pp
collisions
Quarkonium
Today’s Talk: Where we are on road to the Physics

J. Lewis
Results from Summer 2002
b and c Physics at the Tevatron
2
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
J. Lewis
b and c Physics at the Tevatron
3
Run 1: b J/y

Rich and pure channel
 Highlights: Lifetimes, production,
B0 J/y KS0
Bc, first hint of CP
CDF Run 1
41
sin( 2)  0.7900..44
J. Lewis
Yesterday’s sensation is
today’s calibration
b and c Physics at the Tevatron
4
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
J. Lewis
was offline analysis has moved to Level 2 trigger
b and c Physics at the Tevatron
5
B Physics for Dummies: The 3 R’s

Rate
 Cross
section
 Luminosity
 Trigger

Recognition
 Tagging

Reconstruction
 Extract
the signal
 Minimize the background
J. Lewis
b and c Physics at the Tevatron
6
R #1
Rate
Cross Section

B physics enabled by large cross section
 s(b)~10mb
for pT>5 GeV, |η|<1

~1000 B per second at design luminosity
 Compare to ~10 B per second at Υ(4S) factories

Run 1 total cross section factor ~2 above NLO
predictions
 s=1800
GeV
 Effect seen over many channels
 Energy dependence (630 vs. 1800 GeV) agrees with QCD
J. Lewis
b and c Physics at the Tevatron
8
Theoretical Improvements


Recent work on the non-perturbative physics
Fragmentation functions
from NRQCD-inspired fits to
LEP data (names)
Kniehl, Kramer hep-ph/9901348


Resummation of next-to-leading
logs and retuning of Petersen
fragmentation (e=0.002)
Cacciari, Nason hep-ph/0204025
Looking forward to marriage of matrix-element and
parton-shower Monte Carlos
J. Lewis
b and c Physics at the Tevatron
9
Cross Section: Run 2

First D0 measurement
 Muon
+ Jet
 s=1960 GeV
 b content from PT,rel


Data
PYTHIA
Lepton momentum
perpendicular to jet direction
Expectations for Run 2
tests of perturbative region (pT2»mb2) with large
data samples
 Detailed exploration of non-perturbative region
 ds/dpT (b  J/y) down to pT(b)=0
 Precision
J. Lewis
b and c Physics at the Tevatron
10
Luminosity

Tevatron performance thus far below expectations
 Getting better
luminosity: 3.6×1031cm-2s-1
 Best week: 7pb-1
 Record

CDF:
 80
pb-1 good runs

Excludes studies,
commissioning
Start of CDF
physics data
pb-1 with silicon
 Typical efficiency for
December ~80%
 65
J. Lewis
b and c Physics at the Tevatron
11
Trigger
Electrons: ET,PT>2 GeV
 Muons: PT>1.5 GeV
 Tracks: PT>1.5 GeV
 Displaced tracks

 Typically
require d0>100mm, PT>2 GeV
 CDF SVT resolution ~50mm
 Includes 30mm rms beam width

Differences:
 CDF pipelined
Level 1 allows hadronic B decay trigger
 D0 has |h|<2 low-pT lepton coverage
J. Lewis
b and c Physics at the Tevatron
12
Hadronic Trigger

Nominal cuts
 pT>

2 GeV
 pT1+pT2>5.5 GeV
 Opposite Charge
 Opening Angle
 2º<Df<90º for bc
 20º<Df<135º for pp
 d0>100mm
J. Lewis
Loose cuts (b c only)
 pT>
2 GeV
 2º< Df<90º
 d0>100mm
 Automatically updating
prescale
b and c Physics at the Tevatron
13
R #2
Recognition
(Tagging)
J. Lewis
b and c Physics at the Tevatron
14
What’s 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 < 1.6 GeV
 120 ps resolution
φ →K+K-
J. Lewis
b and c Physics at the Tevatron
15
Expected Tagging Performance
Tag
Jet Charge
CDF
Run 1
0.78 ± 0.14
CDF
Projected
3.0
D0
Projected
4.7
Lepton
0.91 ± 0.15
1.7
3.1
Kaon
--
2.4
--
Away Side Total
1.7 ± 0.2
7.1
7.8
Same-Side Pion (Bd)
1.8 ± 0.5
2.0
2.0
Same-Side Kaon (Bs )
--
4.2
~1.0?
 Both
Experiments relying on forward tracking
and large lepton coverage
J. Lewis
b and c Physics at the Tevatron
16
R #3
Reconstruction
(and results!)
Physics Goals With Two Leptons

CPV in B0 → J/ψ KS0
 Yesterday’s
sensation is today’s calibration
Anomalous CPV in Bs0 → J/ψ φ
 B0 →μμK(*)
 Λb→J/ψ Λ: Lifetime, production, CPV, etc.
 Bc → J/ψ π, J/ψ ℓν
 Quarkonium production

J. Lewis
b and c Physics at the Tevatron
18
D0 on the Road to Physics

Good Resolution from new tracker
 J/ψ
→ μ+μMuon plus central tracking
Muon stand alone system
M = 3.08  0.04 GeV
s = 0.78  0.08 GeV
J. Lewis
b and c Physics at the Tevatron
19
D0 Tracking: Neutral Vees

KS0 → π+ π-
J. Lewis

Λ0 → pπ
b and c Physics at the Tevatron
20
D0: First Exclusive B Decays
B+ → J/ψ K+
 ~5pb-1
 Sample
of 3000 J/ψ
 Outer muon trigger
 pT(μ) > 2 GeV
 pT(K) > 0.5 GeV
 pT(B) > 10 GeV
 Vertex fit χ2 >10
 Lxy >120 μm
J. Lewis
b and c Physics at the Tevatron
21
D0: First Physics

Inclusive b → J/ψX Lifetime
416 ± 30 signal events
 2184 ± 47 prompt J/y’s
 (B) = 492 ± 37 mm (stat. error only)
 Compare to PDG: (B) = 469 mm

J. Lewis

J/ψ Cross Section


5pb-1
Large rapidity coverage
b and c Physics at the Tevatron
22
CDF Results: B Meson Masses
Bs0 → J/ψ Φ
5360.3 ±3.8 ± 2.1
2.9
B+ → J/ψ K+
5280.6 ±1.7 ±1.1

B0 → J/ψ K*0
5279.8 ±1.9 ±1.4
J. Lewis


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
b and c Physics at the Tevatron
23
CDF Results: B+ → J/ψ K+ Lifetime

18 pb-1




154 ± 15 Events
τ+= 1.49 ± 0.14 (stat.) ± 0.04 (sys.)
Compare



Incomplete Silicon Coverage
Run 1: 1.68 ± 0.07 ± 0.02
PDG: 1.674 ± 0.018
Expectation:

Systematics to be greatly
reduced with more data
J. Lewis
b and c Physics at the Tevatron
24
All Hadronic Modes: b→c

Primary goal: Bs-Bs favor oscillations
 a.k.a.
Mixing
 Measure frequency Δms
 Δms /Δmd yields |Vts/Vtd|
up to 5% theoretical
uncertainty
 Important constraint
on CKM

a
 Vub Vcb
 Vtd Vts
g

 Vcd  sin C
Much more physics along the way and beyond
 Masses
 Lifetimes
 Other CP violation studies
J. Lewis
b and c Physics at the Tevatron
25
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

mode: φπ , φ →K+K Δm= 99.28±0.43±0.27 MeV
 PDG: 99.2±0.5 MeV
 Systematics dominated by
fit model and selections
 Can be reduced with
more data
 Decay
J. Lewis
b and c Physics at the Tevatron
26
D0 →h+h- Decays

Measure Cabibbosuppressed branching ratios




J. Lewis
Requires detailed modelling of
detector performance
No particle ID
 Account for both
hypotheses for Kπ mode
10 pb-1 sample
Systematics dominated by
background and acceptance
models
K-π+π0
b and c Physics at the Tevatron
K+K-
K-π+
π+π-
27
Branching Ratio Results


Γ(D→KK)/ Γ(D→Kπ)
= (11.17±0.48±0.98)%
PDG: (10.83±0.27)%
J. Lewis


Γ(D→ ππ)/ Γ(D→ Kπ)
= (3.37±0.20±0.16)%
PDG: (3.76±0.17)%
b and c Physics at the Tevatron
28
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
J. Lewis
b and c Physics at the Tevatron
29
Prompt Charm Fraction

Prompt fraction from d0
distribution


Resolution function from
simulation
Check in KS → ππ sample

J. Lewis
B fraction in several D meson
channels
 D0Kp
16-24 %
 D*pD0
11-20 %
 DKpp
11-17 %
 Dsp
32-40 %
b and c Physics at the Tevatron
30
Charmless B Decays

Extract CP violation from
multiple modes






First signal
Bd→ππ
Bd→Kπ
Bs→Kπ
Bs→KK
Separate Penguin and Tree
d
amplitudes
u
b
u
d
d

d
b
g
d
u
u

3:1 Signal-to-noise
Rates understood

d
J. Lewis
b and c Physics at the Tevatron
Consistent with expectations
after correction for acceptance
31
Sensitivity for γ



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 δγ~5-10°
J. Lewis
b and c Physics at the Tevatron
Bd→ππ
Bd→Kπ
Bs→Kπ
Bs→KK
32
Bs Mixing
Mixing 5σ Discovery Sensitivity
First All-Hadronic Decays

20000
B- →D0π-, D0 →K-π+
56±12
Events
Event Yield
15000
10000
Excluded

S:N
1:2
1:1
2:1
5000
0
J. Lewis
b and c Physics at the Tevatron
33
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
J. Lewis
b and c Physics at the Tevatron
34
Conclusions
CDF and D0 detectors and reconstruction
performing well
 First B signals seen
 Lots of work to do
 Exciting results just around the corner

J. Lewis
b and c Physics at the Tevatron
35