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Recent results from TEVATRON

Yuji Takeuchi (Tsukuba)for CDF and DZero collaborations

16th YKIS ConferenceProgress in Particles Physics 2008

Feb. 18th, 2009

Contents•Latest Results from ∫Ldt~3fb-1

•Top quark•Search for SM Higgs

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CDFD0

Chicago

TEVATRON

MAIN INJECTOR

Tevatron Run IIStill at the Energy Frontier

Tevatron:• The world's highest-energy particle collider• Proton-antiproton collisions at √s = 1.96 TeV• Tevatron is performing really well:

Reach 6 fb-1 and 7~8 fb-1 expected by the end of 2009.

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CDF/DZero

CDF:• 8 layer silicon vertex detector• 8 super layer drift chamber• 1.4T solenoid• Good particle identification (K,)• Central/Wall/Plug calorimeters• Scintillator+drift chamber muon

detectors

DZero:• 8 layer silicon vertex detector• 16 layers scintillating fibers• 2T solenoid• Central/Endcap calorimenters• 1.8T toroid• 3 layer muon scintillator + drift

tubes (Extended muon coverage)

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• Continually establishing new records! – Peak luminosity

~3.5×1032 cm-2 s-1

– Weekly integrated luminosity78 pb-1

– Annual integrated luminosity1.8 fb-1 (US FY 2008)

– Avarage pbar accumulation rate

• 21×1010 pbar/ hour

• Very stable operation– Maximizing integrated

luminosity– 10 weeks shutdown in 2009

summer

Tevatron Status

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Integrated Luminosity

• Integrated luminosities for each US FY– Extrapolation for FY2009:

≳ 2 fb-1

FY 2009

FY08

FY09

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Projected Integrated Luminosity in Run II (fb-1) vs time

0

1

2

3

4

5

6

7

8

9

10

time since FY04

Inte

grat

ed L

umin

osity

(fb

-1)

FY08 start

8.75 fb-1

7.29 fb-1

Highest Int. Lum

Lowest Int. Lum

FY10 start

FY09 start

~ 1.8 fb-1 delivered in FY08

FY2010Fermilab plans to run (if budget allows)

and CDF/DZero are ready– Another 2 fb-1 ， total ~9 fb-1

FY2009Run continues

~2 fb-1, total ~7 fb-1

Shutdown ： 10 weeks from June 1

Tevatron Prospects

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Top Quark Physics

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Top Pair production

Dominant process

10%~20%

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Top Pair Signature

Categorize ttbar events into 3 decay types according to W decay mode

Dilepton• 2 lepton• 2 bjet• MET

All Hadronic• 6jet(2bjet)

Lepton+Jet• 1lepton• 4jet(2bjet)• MET

-1-1QCD

11 MeV) (200 ~ << GeV 1.5

Top quark decays as a naked quark Information on spin polarization and

momentum is directly transfered to decay products

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Top Pair Production Cross-section

• Now better than theoretical uncertainties• Luminosity is dominant source of uncertainty

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(ttbar)/(Z)

• The total uncertainty is decreased by 10% by taking the ratio of the top pair to the Z cross sections

+

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Top Quark Mass

Goal before Run-II started : 3 GeV/c2 with 2 fb-1

Now better than 1%

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Two Breakthroughs in Top Mass Measurements

Matrix Element Method• Use information on

leptons and jets maximally

in-situ Wjj JES calib.• JES (jet energy scale) calibration

using di-jet invariant mass from W• Incorporate JES into likelihood

function– L(Mt)→L(Mt,JES)

– Turn JES systematics into statistics Reduced with statistics of top events

Observables

Matrix element with a given top mass gives p.d.f. of observables

Likelihood function of top mass for a given set of observables

M ｊｊ→ MW

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Top Mass Measurement

World Best. Better than 1%

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W Helicity

• Information on t-W-b Vertex– Really V-A?– Really W boson?

In the standard model

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W Helicity Measurements

• Results support V-A coupling on t-W-b vertex so far

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Search for anomalous top quark couplings at DZero

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Measurement of dσ/dMtt at CDF

Singular Value Decomposition (SVD) of the response matrix

κ/MPl > 0.16 at the 95% CL

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Single Top Production

S-channel t-channel

• Cross-section |Vtb|∝ 2

– No need to assume unitarity of CKM matrix nor three generations of quarks

• On the assumption of CKM unitarity: Vtb = 0.99• 3 generations: Can be derived from Br(t→Wb)

• Important to understand bkg of WH event for low mass higgs (mH<130 GeV) – Benchmark of higgs search in WH

WH ： Single Top ～１：１０

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Single Top Summary

• CDF is now preparing combined results for 3.2fb-1

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Single Top Measurement with ME Technique

Signal region

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Single Top Prospects

• Expected uncertainty on Vtb as a function of ∫Ldt• Uncertainties arise from

– Experiment– Cross-section dependence on Mt– Factorization and Renormalization scales– Parton distribution functions– s

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W Boson Mass Prospects

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W Boson Mass

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W Boson MassWorld average : MW = 80.398± 0.025 GeV/c2

CDF: ΔMW=0.048 GeV/c2 (L=200pb-1)

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W Boson MassUnderstanding the detector

Bremsstrahlung tail

Instantaneous luminosity dependence

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W Boson Mass Prospects

• Single experiment sensitivity better than the current world average expected

• Will significantly improve constraint on the Higgs boson mass

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Constraining the Higgs boson mass

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SM Higgs Search

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Low mass Higgs region:m

H<135 GeV/c2

H → bb dominant decay. Search for associated W/Z production.

High mass Higgs region:m

H>135 GeV/c2

H → WW dominant decay. Gluon fusion production search (gg → H).

Higgs Cross-section and BR

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WHlbbCDF: Updated on Nov 7, 2008• Combined result of NN and

ME+BDT• Improved by 15%• Limit/SM < 4.8 @115 GeV/c2

DZero: Updated on Feb 5, 2009• Limit/SM < 6.7 @115 GeV/c2

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Combined Limits

DZero: Updated on Aug 2, 2008• New WH lbb result NOT

included

WHlbbWHWWW

CDF: Updated on Jan 16, 2009• Updates since last summer

– WHlbb

– WH WWW

– ZH llbb

ZHllbb

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Higgs Exclusion @ Tevatron

• One mass, 170 GeV, excluded @ 95% CL• A 15 GeV window [162:177] excluded @ 90% CL

CDF+DZero combinationUpdated on Jul 30, 2008

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Projections

• CDF+DZero projections assuming they perform the same• Possible improvements:

– Acceptance, Analysis method, jet/MET resolutions, ...

• Good possiblity to see 3 evidence to a Higgs of 160 GeV/c2

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Conclusion

• Tevatron is operating well. Better than ever!• CDF and DZero experiment are ready to run FY2010.

∫Ldt ~ 9 fb-1 is expected.

• Top quark properties are being measured more and more precisely. Mass precision is now less than 1%. Top quark properties are consistent with SM so far.

• We are sensitive to a Higgs of 160 GeV/c2.

• Stay tune for interesting results with ≳ 3fb-1 in 2009!