CDF hot topics

1
CDF hot topics
Sandro De Cecco FNAL INFN Roma 1
2
Outline

• Tevatron performances

• CDF detector and B physics triggers

• Recent and new results
• Bs mixing
• b-hadrons Lifetimes DGs/Gs
• Lb modes
• Charmless Bd,s decays
• Rare decays

• Summary and perspectives

3
Tevatron performances

• CDF II has collected so far 0.8 fb-1 out of gt1
  fb-1 delivered by Tevatron.
• Record peak luminosity is 1.31032 cm-2s-1
• Around 600 pb-1 are available for B physics (good
  tracking detector conditions)
• Current analyses use 180 - 350 pb-1 of integrated
  luminosity

Right on the track of stretched TeV plans
1 fb-1 !
4
The CDF II detector
CDF Tracking System
Particle ID
Lepton ID
Muons CMU, CMP, CMX (?lt1.1)

• dE/dX in COT

Electrons CEM (EM calorimeter) CPR
(pre-shower detector)

• Time Of Flight detector

5
B Physics at pp collider

• All B species produced
• Bu,Bd,Bs,Bc,?b, ?b
• With production fractions
• fu fd fs fL 4 4 1 1
• Acceptance for other B is 20-40

BUT ?(bb) ltlt ?(pp) (65 mb) ? B have to be
selected with specific Triggers
the Secondary Vertex Trigger SVT
Example

• Online (L2) selection of displaced tracks
• based on Silicon detector hits.

? see talk by Mauro DellOrso

• b production is so large (300 Hz _at_ 1032 cm-2 Hz)
  that we could not even cope with writing it all
  to tape! ? trigger quasi-exclusively on specific
  decay modes

6
B physics triggers at CDF II
Conventional at colliders (Run I)
With SVT trigger
2-Displaced tracks PT(trk) gt 2 GeV 120 ?m lt
I.P.(trk) lt 1mm SpT gt 5.5 GeV fully hadronic
modes
1-Displaced track lepton (e, ?) 120 ?m lt
I.P.(trk) lt 1mm PT(lepton) gt 4 GeV Semileptonic
modes
Di-Muon (J/?) Pt(?) gt 1.5 GeV J/? modes down to
low Pt(J/?)0 (Run II)

7
Mixing
8
Bs Mixing
but VtsgtgtVtd ? DmsgtgtDmd
Measuring Dms/Dmd determines Vts/Vtd Lattice
calculation error O(5)
Fit with all constraints (winter 05) ? 0.190
0.044 ? 0.349 0.024
WA experimental limit Dms gt 14.5 ps-1
(95CL) (LEPSLDCDF 1)
9
SM CKM-fit prediction for Dms
SM
New Physics models can allow high Dms
(with all constraints)
(?ms not used)
compatibility plot
Dms 18.9 1.6 ps-1 15.7, 23.0 _at_ 95 CL
?ms 20.5 3.2 ps-1 14.4, 27.1 _at_ 95 CL
If Dms gt 30 ps-1 New Physics _at_ 3s
10
Analysis Strategy

• Bs signal reconstruction
• Flavour specific states
• Bs decay time
• proper time reconstruction
• Lifetime measurement
• Initial flavour of the Bs
• Flavour tagging techniques
• calibrate on Bd mixing

B0 A-scan
? B0 Mixing perform a Blind AMPLITUDE SCAN
A
Dmd 0.5ps-1 ? A 1
11
Two different Bs signatures
Fully reconstructed HADRONIC modes

• Good proper time resolution
• High Bs mass resolution
• Selected by Two Track Trigger (SVT)

SEMILEPTONIC modes

• Missing momentum carried by the n
• Diluted proper time resolution
• Selected by dedicated trigger (lSVT)

12
Flavour tagging
Same Side
Opposite Side
Used for today results
Jet Charge the sum of charges of the b-Jet
tracks correlated to the b-flavour
Soft Lepton (e,m) due to b?lnX l charge
correlated to b-flavour
NOT yet used
Same Side Kaon for B0s is likely to have close
in DR a K. High eD2 is expected
Muon Tag
Calibrate the OS taggers on B0 mixing ?
HADRONIC SEMILEPTONIC
Dmd (0.5030.0630.015) ps-1 (0.4980.0280.015) ps-1
Tot. eD2 (1.120.23) (1.430.09)
13
Bs Amplitude Scan results
Semileptonic

• Sensitivity 8.4 ps-1
• Limit Dms gt 7.9 ps-1 _at_ 95 CL

Semileptonic
Hadronic

• Sensitivity 0.4 ps-1
• Limit Dms gt 0 ps-1 _at_ 95 CL

Hadronic
CDF winter 05 Combined

• Sensitivity 8.4 ps-1
• Limit Dms gt 7.9 ps-1 _at_ 95 CL

• World Average CDF Run II
• Sensitivity 18.2 ?18.6 ps-1
• Limit 14.5 ps-1

? see talk by Marco Rescigno
14
Near future for Dms

• With the SAME data
• Add new tagging algorithms Same Side Kaon Tag
• Add more channels
• Add signals from other triggers
• Improve decay time resolution with PV event by
  event
• With NEW data
• Increased Luminosity (0.8fb-1 on tape!)
• Use new trigger strategies
• 2 SVT Tracks tagging muon at trigger level
  (already in place since summer 2004)

x4 statistics
20 better ct res.

• Hadronic analysis will begin to lead the
  sensitivity
• Start to eat interesting Dms range (expect
  comb. sens. 15ps-1)

15
NEW additional semileptonic B decays

• From the same data (360 pb-1) used
• in mixing analysis
• Use SVT trigger (2 displaced and 2 GeV tracks)
• Select e and m offline
• Allow lower LEPTON PT (4?2GeV)
• Increase the overall acceptance
• of more than X 3

At low Lepton PT, expect more backgrounds from
B?DDX decays
16
? more semileptonic Bs for Dms analysis
2 displaced track trigger
4GeV-lepton 1 displaced track trigger

• Additional new sample overlap with the one
  already used 20
• Effective X 3 more semileptonic Bs yield to be
  used for MIXING
• Expect significant sensitivity increase in
  semileptonic Dms search

17
b-hadron lifetimes and DGs/Gs
18
Lifetimes in semileptonic B decays
http//www-cdf.fnal.gov/physics/new/bottom/050224.
blessed-bsemi-life/

• Largest statistics B sample
• More complicated background

?(B) 1.6530.0290.032 ps,
?(B0) 1.4730.0360.054 ps ?(B)/?(B0)
1.1230.0400.040
B ? 0.017 ps
B0d ? 0.025 ps
B0s ? 0.03 ps
?b ? 0.037 ps

• Full statistics sample still under study.
• Statistical uncertainty expected

_at_ 400 pb-1
19
Lifetimes in fully reconstructed modes

• Test for our ability to understand SVT trigger
  biases
• Very clean samples
• Prerequisite for mixing fits

CDF 05 preliminary result
?(B) 1.6610.0270.013 ps ?(B0)
1.5110.0230.013 ps ?(Bs) 1.5980.0970.017 ps
KK
20
Bs?J/y f and DGs / Gs

• BS ? J/y f ? mm- KK-
• B?VV decays Heavy and Light state decay with
  distinct angular distributions and different
  lifetimes.

• Result (260 pb-1)
• 1/4 heavy - 3/4 light state
• Lifetime - theavy 2 x tlight
• Lifetime difference measures
• same CKM element as
• Dm (oscillation frequency)
• Exciting!! Need more data
• 5 sensitivity by 2009
• Dms 10 ps-1 ? DGS / GS 7
• Test still possible CP violation effect in Bs
  mixing

21
b-Barions
22
Lb modes

• Lifetimes are an important experimental
  reference
• Overlap with B factories ? understanding of
  detector/trigger/analysis biases
• Further test on species not produced at B
  factories

Lb? Lc m X
Theo.
Exp.
C. Tarantino, hep-ph/0310241 Oct 2003
Lb Branching ratios
Lb? Lc p
NEW
http//www-cdf.fnal.gov/physics/new/bottom/050407.
blessed-lbbr/
23
?b Updated knowledge

• Colors
• PDG2004
• CDF contribution beyond current PDG2004

Mass m 5619.9 ? 1.7 MeV/c2
Lb mass
(4.1 ? 2.0) x 10-3
Lc l u
(5.5 ? 1.8)

pK pp
lt 2.2 x 10-5
Lc p- p- p
seen
Lc(2593) l u
seen Lc(2625) l u

seen
Sc p-l u
seen
Sc0 pl u
seen
24
CP violation and charmless B decays
25
Charmless B?hh

• Difficult competition with B factories for
  t-dependent tagged measurements
• Interesting B physics measurement of Bs BR and
  ACP(B0?Kp)

• Signals overlap within mass resolution
• Kinematic and dE/dX to disentangle components in
  a combined fit

Future measure Bs lifetime in the CP even mode
KK ? extract DGs/Gs
? see talk by Simone Donati
26
Charmless B?VV decays
? see talk by Simone Donati

• Measured BR( Bs?ff) with 8 events (180 pb-1)
• Update with 360 pb-1
• Will go soon for Polarization Amplitude analysis
• Expected significance similar to B-factories

Future measure DGs/Gs in Bs? ff penguin mode
Bd?fK
Bs?ff
Bs?J/yf
125 events
44 events
225 events
TTT data overlap with 2m trigger 20
27
Search for Bs,d? mm
? see talk by Sinead Farrington
SM BR(Bs???) lt 3.810-9 Sensitive to new physics
Ex.
NEW Results (360 pb-1) BR(Bs ? mm) lt 1.610-7 _at_
90 CL lt 2.110-7 _at_ 95
CL BR(Bd ? mm) lt 3.910-8 _at_ 90 CL
lt 5.110-8 _at_ 95 CL These are currently
world best limits
28
and also at BEAUTY 05

• Other VERY INTERESTING results from TEVATRON
  Heavy Flavour physics on
• Bc meson at CDF and D0
• X(3872) at CDF and D0

? see talk by William Wester
? see talk by Ulrich Kerzel
29
Conclusions

• CDF performed the first Bs mixing analysis in run
  II
• We foresee a substantial update with new samples,
  new data collected and improved tagging power for
  winter 2006
• Working to have world class measurements on
  b-hadron lifetimes and lifetime difference DGs/Gs
• Perform complementary studies in the field of
  charmless B decays Bd,s?hh, Bd,s?VV, help
  digging the penguin sector
• Huge CDF legacy of knowledge in Beauty to next
  generation B physics experiments.

30
Backup slides
31
SVT the hadronic B trigger

• Online Impact parameter
• Available at Level 2 trigger (20µs latency)
• ?convolution of transverse size of the beam spot
  with the impact parameter resolution of the SVT

s 47 mm 35 mm 30 mm
SVT resolution
Beam spot size
Impact Parameter distribution
Offline s 45 mm
32
Dms systematic Uncertainties
Hadronic
Semileptonic

• Dilution scale factors and templates
• systematic limited from control sample
• statistics

• Physics background at low Dms
• Prompt background at high Dms

Systematic errors are negligible with respect
to statistical in both cases
33
Heavy Flavour Production
bb
from Hb??X in 37 pb-1 of data!
PRD 71, 032001 (2005)
with first 6.5 pb-1 !
cc
Pt gt GeV/c ?(ylt1) ?b
D0 5.5 13.3?0.2?0.5
D 6.0 5.2?0.1?0.8
D 6.0 4.3?0.1?0.7
Ds 8.0 0.75?0.05?0.22
PRL 91, 241804 (2003)
34
Excited Heavy Flavor states

• B(L1) ? B?
• B ?J/?K and D? modes
• Important to understand impact for Same Side Kaon
  tagging ? mixing

35
Welcome back to Bc
http//www-cdf.fnal.gov/physics/new/bottom/050330.
blessed-bc-jpsimu/

• Mode that gave the first evidence of the Bc (CDF
  Run I)
• Large yield, no clean resonance though!

106 events
46.0?7.3 events

• First signal of fully reconstructed Bc
• Direct mass measurement!

Hep-ex/0505076
36
Lifetimes J/? modes
http//www-cdf.fnal.gov/physics/new/bottom/040428.
blessed-lft2/

• This was the starting point
• Clean unbiased sample
• Precision measurement
• Reference for biased (e.g. displaced track)
  triggers
• Test for the understanding of
• Detector
• Analysis technique
• Sample composition

37
Lifetime in the hadronic Bs modes

• Decay time
• actually measure transverse quantities
• Lxy , PT(B)
• Un-binned likelihood fit
• Used and

Combinatorial background ct template from high
mass sideband
38
Hadronic B-lifetimes results
CDF
(stat) (syst)
Systematic summary
t(B) 1.66 0.03 0.01 ps t(B0) 1.51
0.02 0.01 ps t(Bs) 1.60 0.10 0.02 ps
t(B)/t(B0) 1.10 0.02 0.01 t(Bs)/t(B0)
1.06 0.07 0.01
World Average lifetimes (exp.)
Theory prediction (see Cecilia Tarantino CKM05)
t(B) 1.653 0.014 ps t(B0) 1.534 0.013
ps t(Bs) 1.469 0.059 ps
t(B)/t(B0) 1.06 0.02 t(Bs)/t(B0) 1.00
0.01
39
Lifetime in the semileptonic Bs modes
ct 455.9 ? 11.9 mm
ct 422.6 ? 25.7 mm
ct 413.8 ? 20.1 mm
Combined l-Ds lifetime result 445.0 ? 9.5 mm
(W.A. 438 ? 17 mm)
statistical err .only, ?NOT for
Averages? (DØ 05 426 ? 13 ? 17 mm)
Real Ds backgrounds prompt and physics
40
HQET baryon lifetimes and B moments
B lifetimes ? Vcb Dominant uncertainty comes from
HQET extraction! CDF can probe HQET and constrain
it!
?b lifetime
http//www-cdf.fnal.gov/physics/new/bottom/030710.
blessed-lambdab-lifetime/
C. Tarantino, hep-ph/0310241 Oct 2003
LO
NLO
LO
NLO
LO
NLO