FNAL Users’ Meeting, 06/02/03, p. 1 Top and Electroweak Results from CDF Igor Volobouev LBNL for the CDF Collaboration.

FNAL Users’ Meeting, 06/02/03, p. 1

Top and Electroweak Results from CDF

Igor Volobouev

LBNL

for the CDF Collaboration

CDF

FNAL Users’ Meeting, 06/02/03, p. 2Igor Volobouev

Top / Electroweak Program

• Measurement of fundamental parameters Calibration (e.g., MZ ) Precision measurements of Mtop, MW, Vtb, etc.

• Tests of Standard Model predictions Cross sections, branching fractions, kinematical

distributions, lepton universality Top quark properties: unique to CDF/D0

• Searches for new phenomena Higgs Anomalous couplings, new particles and resonances, rare

and forbidden decays

• Discovery potential exists in all areas

CDF


TOF

=2

=3

=1

CDF Run 2 Upgrade

• Improved Si coverage || < 2 up to 8 layers

• New central tracker 96 layers

• Time of Flight

• Expanded muon system

• Forward calorimeter

• Trigger and electronics

= -ln(tan(/2))

CDF


Run 2 Data Sample

• Total current sample on tape: 175 pb-1

• “Winter analyses” sample: 56-91pb-1

• 4-9 pb-1/week90% efficiency

“Winter” sample

Commissioning

DeliveredOn Tape

Store Number

Tot

al L

umin

osity

(pb

-1)

CDF


Electroweak Measurements

• Unambiguous predictions from the Standard Model, world averages, Run 1 measurements W, Z production cross sections Lepton universality Forward-backward asymmetry Di-boson production

• “New physics” reach at a few hundred pb-1

• Data analysis infrastructure Lepton and photon identification W and Z signatures Calibrations Luminosity monitoring

We

Z

CDF


B(Wll)

Events Background •B(Wll) (nb)

e 38625 6% 2.64±0.01stat±0.09sys±0.16lum

21599 11% 2.64±0.02stat±0.12sys±0.16lum

• Clean signature Isolated lepton Missing ET

• High and S/B

• 72 pb-1

W

CDF


Wand Lepton Universality

• Narrow, isolated hadronic jet from

• Missing ET > 25 GeV

• Electrons removed• Relatively low

background ( 26%)

sysstateWBR

WBR07.004.099.0

)(

)(

B(W) = 2.62 ± 0.07stat ± 0.21sys ± 0.16lum nb

CDF


B(Zll)• Two leptons: negligible

background (< 1%)• Used for calibrations: energy

scale, resolutions

l =e: 267±6stat±15sys±16lum pb

l =: 246±6stat±12sys±15lum pb

CDF


AFB with Z0/* e+e-

• Forward-backward asymmetry:)0(cos)0(cos

)0(cos)0(cos

dd

ddAFB

• Probes /Z interference, sensitive to new physics

• High mass reach is unique to Tevatron

• Measurement is consistent with the SM prediction

CDF


• pp W, Z, WW• Depend on trilinear gauge

couplings (s-channel):

• Events found expected W Z WW 4.3

• Results are statistics-limited, consistent with the SM predictions

Di-boson Cross Sections

W

W

q

q'81 events

CDF


Top Quark Measurements

• Main question: is top quark adequately described by the Standard Model?

• Run 2 results so far: Cross section Top mass

• Many precision tests of top to come with more data

• SM: tt production cross section at 1.96 TeV is 30% larger than at 1.8 TeV

Top spin polarization

Production Cross Section

Resonance production ?

Production kinematics

CDF


Dilepton Cross Section

• Signature: 2 leptons, 2 jets, missing ET

• Backgrounds: WW, Z , Drell-Yan, fake leptons

• Event selection: signature and Scalar transverse energy > 200 GeV Background rejection: photon

conversion veto, Z veto, lepton isolation, for missing ET

• Found 5 candidates, expected 0.3 background events

tt =13.2 ± 5.9stat ± 1.5sys pb

CDF


Lepton + Jets Cross Section

Control Signal15 candidate events with b tags, 3.8 background

tt = 5.3 ± 1.9stat ± 0.8sys pb

CDF


Lepton + Jets Cross Section

Control Signal15 candidate events with b tags, 3.8 background

tt = 5.3 ± 1.9stat ± 0.8sys pb

CDF


tt Cross Section Summary

hep-ph/0303085 (M. Cacciari et al)

CDF


Top Quark Mass

• Lepton + jets channel: Run 1 CDF result was

176.1 ± 6.6 GeV/c2

• Statistical error is mainly due to jet combinatorics. Mtop with b tags will be presented at the summer conferences.

• Systematic errors will dominate the uncertainty Jet energy reconstruction MC top decay modeling Background

33 events

CDF


Future Run 2 Measurements

• Electroweak Drell-Yan at high mass

(PDFs, new physics) W charge asymmetry Direct W width pp WZ, ZZ, trilinear

couplings MW with 40 MeV/c2

precision (400 pb-1 are needed if 1/L scaling holds)

• Top Analysis of production and

decay kinematics– Resonant production

– W helicity

– Spin correlations

Single top production Vtb

Rare and forbidden decays Mt with 3 GeV/c2

precision

Many of these measurements are already in the works

CDF


Higgs ConstraintCurrent SM Higgs fit: MH = 81+52

–33 GeVLEP 2 direct search limit: MH > 114.4 GeV at 95% CL

CDF


Summary

• A variety of Run 1 results have been reestablished We are confident that CDF components are working as

expected and the system integration was a success Our understanding of the CDF detector is improving. We

have already developed many building blocks needed for taking on really challenging physics problems.

• So far, top and electroweak results are consistent with the Standard Model predictions

• Most measurements are statistics limited, and will benefit from larger datasets

• Expect many new and improved Run 2 results this summer and during the next few years

CDF


Backup Slides

CDF


Electron Identification

• CEM transverse energy ET > 20 GeV

• Track pT > 10 GeV/c

• Track |z0| < 60 cm

• ET/pT < 2.0 when ET < 50 GeV

• Cluster EHAD/EEM < 0.055 + 0.00045 * E

• Track-to-shower match 3 cm

• Fractional calorimeter energy isolation < 0.1

• Shower profile consistent with electron

• Fiducial to CES

CDF


Muon Identification

• Track pT > 20 GeV/c

• Track |z0| < 60 cm

• Cosmic ray veto

• EEM < 2 + max(0, 0.0115 * (p - 100)) GeV

• EHAD < 6 + max(0, 0.0280 * (p - 100)) GeV

• Fractional calorimeter energy isolation < 0.1

• Track match to a muon chamber stub: 3, 5, and 6 cm for CMU, CMP, and CMX, respectively

CDF


B Jet Tagging with SVX

• At least two well-reconstructed tracks with 3 silicon hits

• Secondary vertex LXY significance at least +3• Efficiency in tt events: 45 1 5 % for “taggable” jets

CDF


Weekly Delivered Luminosity

CDF


Downtime and Deadtime

• Downtime – much better when we keep taking data…– HV Trips (COT, Silicon, muon, etc.) (not so often these days)– L3/EVB/CSL/L2, etc. (comes/goes in wave. Right now, it is good)– HRRs (bunch counter errors, TDC done timeout, etc.)– Trigger table tests, 2 SRC tests, XFT tests… (future investment)– Startup time, waiting to bring up HV at beginning of the store– Silicon D-mode calibration and other odds and ends– Downtime due to operator errors are very small

• Dead time – much easier when lumi is low and trigger rates low, but…– L1/L2 busy dead time (much work in progress, eg. 2SRC readout)– Hitting CSL output limit -- design 20Mb/sec. This current problem should be

solved by:• Tightening (wisely) trigger filters, limiting L3 output rates• Dropping L3 reconstruction banks and other diagnostic banks• Compressing silicon/COT raw data banks, etc.

– However, at the same time, we are also reviewing/studying the possibility/consequence of extending the current CSL 20Mb/sec limit

CDF


Di-boson Run 2 Results

Cross section for ET() > 7 GeV, R > 0.7 :(W) = 17.2 3.8(stat.) 2.8(sys.) 1.0(lum.) pbSM: (W) = 18.7 1.3 pb

W, electron channel

(W) = 19.8 4.5(stat.) 2.4(sys.) 1.2(lum.) pbSM: (W) = 18.7 1.3 pb

W, muon channel

= 5.8 1.3(stat.) 0.7(syst.) 0.3(lum.) pbSM: = 5.3 0.4 pb

Z, combined

WW: expected 2.8 signal and 1.5 background events (SM), found 2

FNAL Users’ Meeting, 06/02/03, p. 1 Top and Electroweak Results from CDF Igor Volobouev LBNL for the CDF Collaboration.

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