Tevatron Physics Results – Implications for the LHC*

Paul Grannis, for the CDF and DØ collaborations

ATLAS Physics Workshop, Aug. 3 2009

* What about dem Mets?

Operations Fermilab expects to run the Tevatron through FY2011. The Tevatron is now delivering close to its upper projection L.

Detector subsystems should (almost) survive for 12 fb-1 of data. (DØ silicon shown here; Layer 0 is OK; inner detectors on layer 1 barrel not fully depleted after ~9 fb-1.)

now

Summer ’09 results up to 5.8 fb-1, typically ~ 4fb-1

90%

DØ efficiency to tape (93% in April). 80% of total delivered gets into analyses.

Expect 12 fb-1 delivered; 10 fb-1 to physics

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Physics outputNow ~100 papers/year. Recent results based on 3–5 fb-1 so final data set will be 2–3X current.Many analyses still improving faster than 1/L1/2 due to improvements in techniques

No further upgrades to detectors; triggers are now stable.

Physics analyses in CDF and DØ based in six working groups:

Top quark properties

Electroweak bosons

Heavy flavor (b,c) states

Searches for phenomena beyond the SM

QCD studies

Higgs boson searches

This talk will select only some

highlights of interest to initial

LHC program (and those that will

be Tevatron legacy). Many

results will be updated for Lepton

Photon.

Publications by year CDF + DØ

CDF and DØ are now taking students (~10/expt) who did ATLAS/CMS hardware and commissioning to do Tevatron physics analyses for theses. A good match!

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Top quarkTop quark mass:

Tevatron average Mt=173.1±1.2 GeV (0.7%)

Have now exceeded the Tevatron goal; expect the final average mass to be below 1 GeV. Are now reaching the systematic limit (heavy flavor jet energy scale, signal model, jet resolution).

Reaching this precision will take LHC experiments a while.

Best single top-antitop cross section measurement (CDF) is ±8% and uses the Z cross section to reduce normalization uncertainty. Consistent with theory for the measured Mt. Final systematic limit should reach ~6%, less than the 10% theory error.

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Top properties

Top-antitop mass difference 3.8±3.7 GeV

Top charge = 4e/3 excluded at 92% CL

* AFB=0.193±0.069 (3.2 fb-1)(NLO QCD: 0.05±0.015)

W helicity in t decay: p=23% to see larger SM discrepancy than observed. With 8 fb-1 and same central value, p=0.0024.

Hint of t’ quark?

t t resonance excluded to 820 GeV. (Are already into LHC regime where jets from boosted tops merge, so kinematic fitting is not optimum.)

All statistics limited; hints of non-SM behavior exist so stay tuned. ( * = Tevatron legacy) 5

SM

DØ

DØ preliminaryf0

* t-t spin correlations:

NLO QCD

(d/dz1dz2=1/4(1Cz1 z2); zi=cosi of lepton i in top rest frame)In NLO QCD, C=0.777. C=0.32 (CDF). DØ is 2from QCD.

+0.55 0.78

EW single top production

t-channel W*b*ts-channel W*tb

Signal is small; background is large. Analyses pull all the stops (BDT, BNN, ME, L fns). Both CDF/DØ now at 5 (3.2/2.3 fb-1). Analyses are statistics limited.

New result: 4.8 significance for t channel process alone. Separate s- and t-channel XS; sensitive to BSM physicsWith full data set:

ExpectVtb/Vtb ≈ 0.08 Sensitive to W’ > 800 GeV H± search with MH > Mt

Anomalous top couplings

Final state is tb = bbW

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t = 3.14 pb+0.94 81

Combining W helicity and single top

W boson massRecent DØ measurement (1 fb-1) gives MW=80.401±0.043 GeV (CDF 80.413±0.048 GeV in e & , 0.2 fb-1).

Requires control of systematics to 10 level (energy scale, recoil system calibration, QED/QCD modeling). Precision is statistics limited (mainly Z statistics) so will improve.

Expect 2009 Tevatron (World) average MW

with errors ≈31 (23) MeV. (Tevatron M < LEP M)

With 10 fb-1, expect error ~16 MeV/expt (~12 MeV combined), so world average MW≈10 MeV.

This will be a challenge for LHC experiments to match! But the overconstraint on SM with LHC Higgs will be very strong.

MW

Mt

W error

top error

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ultimate

ultimate

W/Z measurements d/dpT

Z measures QCD resummation parameter g2 and is needed to reweight MC backgrounds for rare processes.

New direct measurement of W± asymmetry: more precise than current PDF errors, so will constrain future PDF fits.

Direct measurement of W boson width from high transverse mass tail; now WA uncertainty with 1 fb-1 of ~45 MeV. Project WA after 10 fb-1 ~20 MeV (better than the current indirect measurement from W/Z xBR ratio of 42 MeV)

AFB for qq Z* ll measures sin2W for light quarks (recall the LEP/SLC discrepancy between sin2W for leptons and heavy quarks). With 10 fb-1, will have comparable precision for light quarks as LEP/SLD for b-quarks. AFB at high mass probes new physics.

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Diboson cross sections

At Tevatron, W, Z, WW, WZ, ZZ processes have the smallest SM cross sections apart from Higgs. With the DØ 5.7 observation of ZZ last summer, all have now been observed.The diboson processes are important for several reasons:

Search for anomalous trilinear couplings (here LHC will do much better)

They are backgrounds for even rarer processes (EW production of top, Higgs, …). Give experimental guidance on NLO/LO k-factors.

Demonstration of techniques for Higgs search using a ‘known’ rare process.

Diboson measurements are dominated by statistics, so increase in data samples will help considerably.

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dijet mass in 2 jet+missing ET (1st observation of WW,WZ,ZZ in semihadronic channel.)

CDF 3.5 fb-1

CP in BS

system

S= SSM + NP

SSM=0.04 ± 0.01

CDF+DØ combined see 2.0 deviation from SM in joint fit of S vs. S for BS → J/ thus hinting at new phenomena beyond the SM.S = L – H = 2|12|cosS

+0.37 0.33

BS → J/ , BS → DS ± charge asymmetry; dimuon charge asymmetry (++ vs. ); time dependent BS → DS

+X will all provide further constraints on S:

More data, use of multiple analyses, and improved event selection and BS – BS tagging can give significant non-SM indication. If current central value holds, can reach 5 discovery on non-SM physics.

± Projection for BS → J/ only, 1 exp’t and no projected improvements.

Measure S rad (BS J/ )

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S = 2S

b-quark physicsTevatron produces heavy b-

quark hadrons inaccessible at B-factories:

Have added to b(udb) seen by UA1: b

± (uub, ddb), b(dsb), b(ssb)

(CDF & DØ b masses do not agree)

Extensive studies of BC, BS mesons

Increased statistics will improve mass, lifetime measurements, BS

mixing,. All are important for confronting HQETpredictions and understanding non-pQCD.

August 2008

M=6054.4±6.9 MeV

CDF 4.2 fb-1

M=6165±16 MeV

Rare b-hadron decays probe new non-SM physics. In MSSM, BS→ rate is enhanced by tan6Expect ~10xSM per experiment (10 fb-1).

And new surprises continue: evidence for ‘charmonium’ state Y(4120) J/KK

M(KK)-M()

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Searches for new

phenomenaCDF and DØ have searched for many states expected in Susy, strong coupling, large extra dimension models with no clear signals to date.

RS graviton ZZ

Squark search in jet + + MET

Neutralino/chargino search in trileptons

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CDF

Search for in GMSB with

G . Approaching the cosmologically favored region.

~

Searches for new

phenomena

… but we hear the locomotive coming on the tracks behind us, and look forward to some real news on SUSY soon.

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We are gratified with these improvements …

MSugra limits are improving beyond LEP limits, due to high statistics and new techniques.

For example

Now searching in new model contexts.

In NMSSM, new light a states, with h aa (athat defeat the SM Hbb search limits. HyperCP saw a hint of a 214 MeV “a” boson in p. With full Tevatron sample, can exclude the NMSSM in much of the allowed range.

Hidden valley models postulate a hidden sector weakly coupled to SM. SM Higgs couples to HV higgs HV with couplings that could be large: HV bb. Get limits as f(MH, MHV, decay length). Now exclude for small MHV, DL.

New phenomena

Neutralino can decay to HV “dark photons” and “darkino” with DARK lepton jets. Searches now begin to exclude regions of phase space.

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QCD studies Inclusive jet production to very large pT and rapidity, favoring lower gluon content at large x.

Studies of pQCD and non-p QCD have extended HERA and LEP measurements. The detectors and algorithms are now well calibrated. Techniques and PDF constraints are valuable for early LHC running.

d/d distributions (would be flat for Rutherford scattering) are sensitive to new physics contributions. New limits set on quark compositeness, RS extra dimensions, ADD extra dimensions.

d/dMjj distributions at high mass and large rapidity constrain PDFs. Data/theory ratio now distinguishes CTEQ6 and MSTW predictions.

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DØ data

Z+jets production

W/Z+jets production is an important test of QCD, and is a major background for top quark studies and many searches such as Higgs bosons & trilinear gauge boson couplings. LHC analyses will require good understanding of these.

Recent studies of Z+jets, unfolded from pT

jet(meas) to pTjet(true)

to confront predictions with various event generators. Jet cone (R=0.5) is used.

Meas vs true pT migration matrix

pTjet yjet pT

Z yZ

These comparisons generally show agreement within errors for NLO pQCD (for pT

Z > 45 GeV). ALPGEN shapes are OK, but normalizations are off. SHERPA and PYTHIA have shape disagreements.

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Z+b jet measurements are key inputs for many searches; now being measured at the Tevatron.

SM Higgs boson

March 2009 combination channels

WH: e/ bb bb qq’

eW(e/)W(e/)jj bb

ZH: ee/ bb bb bb qq

ttH: lb qq’b bb

gg→H: W(e/)W(e/) (+ 2 jets)

WW →H: (+ 2 jets)

Low mass Higgs (MH < 135 GeV):

mainly sought in associated WH/ZH production; high mass (MH

> 135) mainly in gluon-gluon fusion:

Mar. 2009: next update at Lepton Photon 17

The advanced multivariate and statistical techniques used for the W/Z +H search are now verified in the similar W(l) W/Z(qq) production.

Measure 20.2±4.4 pb (16.1±0.9 SM) : 4.4 significance. Would like to extend this to W(l) Z(bb) to also test b-tagging and lower signal/background ratio.

SM Higgs bosonDirect Higgs search confronts the

SM indirect measurement allowed region.

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SM Higgs boson

Improvement faster than L-1/2

better b-tagging lepton ID improvements more channels better background models larger kinematic regions jet E resolution improve

10 fb-1

With 10 fb-1 analyzed, expect to be able to rule out SM Higgs to >180 GeV, and have shot at evidence below ~120 GeV.

Probability for 3 evidence in 10 fb-1.

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SUSY Higgs

hb bbbh hb b

Previous searches for Susy higgs were in separate channels. The sensitivities of these are comparable

New combined limit from all three processes – 1 – 2.6 fb-1

Closing the gap on low mA Susy higgs in the interesting region (tan ~ 3540) where tan ≈ mt/mb

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ConclusionsWe expect the delivered luminosity from the Tevatron to increase to ~10 fb-1 (analyzed) by the end of the run, an increase by a factor of ~2–3. Analysis improvements will add also sensitivity. These allow substantial improvements for: Low mass Higgs search W mass Diboson production Top quark mass Electroweak production of single top, Vtb

Heavy b-quark states and CP violation in BS

Resolving hints of new phenomena

Difficult for LHC

CDF & DØ are running smoothly and efficiently; no indications of detector problems. Collaboration strengths are sufficient to carry out the program.

We are having fun but feel like the warmup act for the star performer. Good luck, and I hope you blow us out of the water

before long.