1 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London Beyond the Standard Model Searches...

1Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London

Beyond the Standard Model Beyond the Standard Model Searches at the Tevatron Searches at the Tevatron

Beyond the Standard Model Beyond the Standard Model Searches at the Tevatron Searches at the Tevatron

Gérard Sajot

LPSC Grenoble

On behalf of the CDF and D0 Collaborations


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OutlineOutlineOutlineOutline

Recent CDF and D0 results from “RunIIa” 1.1 fb-1 (April 2002-February 2006)

- Leptoquarks - Compositness lepton - 4th generation of quarks - Extra Gauge Bosons W’ Z’ - Extra Dimensions Monojets, di-leptons and di-photons

Not covered in this talk : - SUSY : talk by Volker Buescher (plenary July 4th) - Technicolor, Little Higgs - …

See also CDF+D0 talk by Tommaso Dorigo (parallel session July 3rd)


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Leptoquarks Leptoquarks Leptoquarks Leptoquarks

LQ : predicted by models Beyond Standard Model (GUTs, Technicolor, SUSY..)

Color-triplet scalar (spin=0) or vector (spin=1) bosons carrying lepton and quark quantum numbers Three generations, each coupling to one lepton generation only (lepton number violation, FCNC)

LQ Production at Tevatron: dominant q qbar/g g -> LQ LQbar

scalar leptoquarks : (s, mSLQ)vector leptoquarks : (s, mVLQ, G,G)

At Tevatron searches are mainly for pair production of Scalar LQ

-> CDF VLQ3 2+2b (322 pb-1) M > 251 GeV (minimal coupling) M > 317 GeV (Yang-Mills coupling) submitted -> D0 : single production of SLQ2 for a luminosity of 300 pb-1 PLB 647, 74 (2007) -> more on back-up slides


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22ndnd generation LQ generation LQ D0 1 fbD0 1 fb-1-122ndnd generation LQ generation LQ D0 1 fbD0 1 fb-1-1

LQ2LQ2 qq Background : ->W+jets, Z+jets -> ttbar-> QCD : from data

Basic Selection : - 1 ||< 2, pT>20 GeV - at least 2 jets || <2.5 pT> 25 GeV - MET> 30 GeV (not aligned with to minimize mis-measured MET) - MT() > 50 GeV (to reject QCD background)

= BF(LQ2 -> q) Br( LQ2LQ2 qq)= 2 (1-)


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22ndnd generation LQ generation LQ D0 1 D0 1 fbfb-1-1

22ndnd generation LQ generation LQ D0 1 D0 1 fbfb-1-1

Optimized cuts (done for m(LQ) = 200 GeV) :

- MT() > 160 GeV (W background)

- Scalar Transverse Energy ST= pT()+pT(jet1)+pT(jet2)+MET>350GeV

- M(jet1) > 150 GeV (related to LQ mass) - the jet combination with the invariant mass closest

to the searched LQ : |M(jet)rec-M(LQ)gen| < 100 GeV

D0 at 95%CL MSLQ2>214 GeV for =0.5

D0 Data 6

Total Bkg 6.4 0.7 0.8

Efficiency mLQ=200 GeV

0.079 0.001 0.007

Previous SLQ2 results170 GeV CDF RunII jj 198 pb-1

208 GeV CDF RunII combined jj and jj and jj

198 pb-1

204 GeV D0 RunII combined

294 pb-1


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Search for f*Search for f*Search for f*Search for f* Several models postulate that quarks

and leptons are composed of scalar and spin-1/2 particles :

-> large spectrum of excited states : e*, *, q* -> contact interactions (CI) between quarks and leptons

CDF -> e* (202 pb-1, 2005) -> * (371 pb-1, 2006)

D0 -> * (380 pb -1, 2006) -> e* for the first time - production via CI - decay via gauge interaction (e*-

>e, W, eZ) or CI e*->effbar)

Search in ee


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Search for e* Search for e* D0 1.0 fbD0 1.0 fb-1-1Search for e* Search for e* D0 1.0 fbD0 1.0 fb-1-1

Selection : - trigger on single or di-electron - 2 isolated electrons with ET > 25 GeV, ET> 15 GeV - 1 isolated photon with ET> 15

GeV

Background dominated by - DY+-> ee - DY+jet -> ee “fake ” Estimated from ee data

Search for a peak in me

Data : 259 events Total Background 232329

events

Expected if me* = 300 GeV


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Search for e* Search for e* D0 1.0 fbD0 1.0 fb--

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Search for e* Search for e* D0 1.0 fbD0 1.0 fb--

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D0 limits at 95% CL me* > 756 GeV for = 1 TeV me* > 946 GeV when neglecting CI decays and for = me*

improving previous CDF RunII limit me* > 879 GeV 202 pb-1

Parameters : me* , (compositeness scale)


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44thth generation quark : b’ ->bZ generation quark : b’ ->bZ CDF 1.1 CDF 1.1 fbfb-1-1

44thth generation quark : b’ ->bZ generation quark : b’ ->bZ CDF 1.1 CDF 1.1 fbfb-1-1

b'b‘bar -> bZbZ -> bllbqq (l=e or )

Selection : - blind analysis - Z->ee or , pT(z) >20 GeV - Njet

30 3 (number of jets ET> 30 GeV, ||<2) - JT30 > X ( JT30 = scalar sum of ET of all jets in the event with ET > 30 GeV and ||<2)

Background : Z+jets Predicted from the data by fitting the ET distributions in Njet

30 =1 and 2 and modeling JT30.

10% uncertainty on acceptance X efficiency (dominated by 6.7% Jet Energy Scale)

CDF Mb’ > 270 GeV if BR(b’->bZ)=100%


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W’->eW’->e D0 900 pbD0 900 pb-1-1 W’->eW’->e D0 900 pbD0 900 pb-1-1

Predicted in many beyond-SM scenarios:Left-Right-Symmetric models, GUT models which may also imply SUSY(e.g E_6), …

Search assumes : - a SM-like W’ (same couplings). - w’ = 4/3 mw’ /mw w (factor 4/3 if w’->tbbar is possible, i. e. mw’ > 180 GeV)

Selection : - isolated central electron (||<1.1) ET > 30 GeV - MET > 30 GeV Background : - W-> e, - WW, WZ, ZZ, ttbar - QCD background estimated from data (low mT region)


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W’->eW’->e D0 900 pbD0 900 pb-1-1 W’->eW’->e D0 900 pbD0 900 pb-1-1

Further selection : mT > 150 GeV ->Data : 630 events ->Total Background : 623 18(stat) +83-75(syst) events

D0 Limit : binned likelihood of M_T distribution M W’ > 965 GeV


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Search for resonant tbbar production W’ -> tbbar -> Wbbar –>ljj

Method : use the single top samples and same W+jets event selection Selection : - exactly 1 lepton (e or ) PT> 20 GeV - MET > 25 GeV - 2 or 3 jets ET>15 GeV ||<2.8 - at least 1 jet with a displaced secondary vertex

CDF Limits at 95% CL : Interference W/W’ neglected (mw’ >> mw ) L-handed and R-handed W’ models - if MR < M W’

W’R can decay to R-handed leptons -> MW’ > 760 GeV -if MR > MW’ -> MW’ > 790 GeV

W’ resonances W’-> tb W’ resonances W’-> tb CDF 955 CDF 955 pbpb-1-1

W’ resonances W’-> tb W’ resonances W’-> tb CDF 955 CDF 955 pbpb-1-1

D0 : PLB 641, 423 (2006) 230 pb-1 Mw’ > 610 or 670 depending on model


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Z’->ee Z’->ee CDF 1.3 fbCDF 1.3 fb-1-1 Z’->ee Z’->ee CDF 1.3 fbCDF 1.3 fb-1-1

Selection : - 2 electrons ET > 25 GeV at least one in central calo (||< 1.1)

Background : Dominated by Drell Yan (irreductible) Smaller contribution from di-jet, W+jet, W+,

CDF : are excluded at 95% CL Z’SM < 923 GeV E6 : ZI < 729, Z < 822, Z < 822, Z < 891 GeV


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Gravity is localised on a (3+1)-dimensional brane, the Planck brane, separated from the standard model brane in a 5th dimension with warped metric.In simplest version : only graviton can propagate in the 5th dimension Due to the warped metric their wave functions are exponentially suppressedaway from the Planck brane (so gravity appears weak) Gravitons appear as KK excitations

Parameters of the model : - M1, the mass of the first excitation - the dimensionless coupling to the standard fields 0.01 < (8)1/2/MPl < 0.1

(limits : consistency with electroweak data and model remains perturbative)

Graviton decays to ffbar and to diboson pairs. Br(G->)= 2 Br(G->ee) spin G=2

Randall-Sundrum GravitonsRandall-Sundrum GravitonsRandall-Sundrum GravitonsRandall-Sundrum Gravitons


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RS Gravitons G->ee or G->RS Gravitons G->ee or G-> RS Gravitons G->ee or G->RS Gravitons G->ee or G->

Selection : - 2 central (|| < 1 electromagnetic objects with ET> 25 GeV

Background : - DY and di-photon (PYTHIA) - QCD estimated from data

mee and m combined

Example : search Selection : - 2 photons with ET > 15 GeV - m > 30 GeV

Background : - SM di-photon (Diphox) - QCD jets faking photons estimated from data

CDF 1.1-1.3 fb-1 D0 1.1 fb-1


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RS Gravitons G->ee and/or G->RS Gravitons G->ee and/or G-> RS Gravitons G->ee and/or G->RS Gravitons G->ee and/or G->

(8)1/2/MPl M1 limit (GeV)

0.01 240

0.1 865

Best direct limit to date

D0CDF(8)1/2/MPl = 0.1 M1 limit

(GeV)

ee alone 807

ee+ 889The area below the dashed-dotted line is excluded from the precision electroweak data

CDF 1.1-1.3 fb-1 D0 1.1 fb-1


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RS G->ZZ->4e RS G->ZZ->4e CDF 1.1 fbCDF 1.1 fb-1-1RS G->ZZ->4e RS G->ZZ->4e CDF 1.1 fbCDF 1.1 fb-1-1

Data : 0 events with m4e > 500 GeVBackground : 0 0.02

Signature : Four electron mass peak

Discriminating variables : m4e and 2

Event display of the lowest 2 event


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Arkani-Hamed,Dimopoulos and Dvali Arkani-Hamed,Dimopoulos and Dvali

LEDLED Arkani-Hamed,Dimopoulos and Dvali Arkani-Hamed,Dimopoulos and Dvali

LEDLED Events with Large Missing Transverse Energy and one or more jets are predicted in many models beyond the Standard Model : - SUSY with R-parity conservation, - Technicolor (with technirhos decaying into W and Z) - leptoquarks (decay in neutrinos +jets)

- Models with compactified LED CDF search

ADD MODEL : gravity propagates in the 4 + n dimensional bulk of space-time other SM fields are confined in the 3+1 brane

If compactification on a torus, the effective Planck scale MD and the radius Rn of the extra dimensions are related by : Rn= 1/8 (MPl/MD)2 /MD

n

If R large enough (O(10m)), MD could be of the order of 1 TeV Production at Tevatron : q+qbar/g+g G+g, q+g G+q

G escapes undetected in the bulk of ED

GKK

gq

q GKK

gg

g

-> topology single jet + MET


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ADD LED ADD LED CDF 1.1 fbCDF 1.1 fb-1-1ADD LED ADD LED CDF 1.1 fbCDF 1.1 fb-1-1

Signature : jets+ MET

Selection : - leading Jet ET > 150 GeV- MET > 120 GeV- allow 2nd Jet with ET < 60 GeV- no 3rd Jet with ET > 20 GeV

Results: Nobs= 779 Nbkg=81971 mainly Z()+jets

n MD TeV R mm

2 >1.33 <0.27

3 >1.09 <3.1 10-6

4 >0.99 <9.9 10-9

5 >0.92 <3.2 10-10

6 >0.88 <3.1 10-11

LEP + MET ICHEP 2004

CDF 95% CL


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ConclusionsConclusionsConclusionsConclusions

CDF and D0 have performed new (and unsuccessful) searches in many areas for a Lumi ~ 1fb-1 (RunIIa dataset)

Not every conceivable model has been probed, but most final states

Tevatron, CDF and D0 are performing well

Analysis are improving

By the end of 2009, Tevatron is expected to deliver 6 to 7.5 fb-1

CDF and D0 have excellent physics prospects before first LHC results !


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Back-up Back-up Back-up Back-up


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Tevatron is performing very wellTevatron is performing very well Tevatron is performing very wellTevatron is performing very well

CDF and D0 experiments have collected more than 3 fb-1

Record Peak luminosity above 2.8 1032 cm-2 s-1Peak luminosity


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New @ Run IIa (tracking in B-field)

Silicon detectorFiber tracker, preshowers

Upgraded @ Run IIa Muon system, CAL

Electronics DAQ, (track) trigger

system Displaced-vtx trigger

p

Electronics

Tracker Solenoid Magnet

3 LayerMuon System

Preshowers

p

The D0 Detector


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The CDF Detector

Addition or Improvments for the Run IIA Si tracker Central drift chamber TOF4th generation 4th generation

quark : b’ ->bZ CDF quark : b’ ->bZ CDF 1.1 fb-11.1 fb-1

Secondary vertex trigger

Addition or Improvments for the Run IIA Forward calorimeters: "plugs" (1<||

<3) Extended coverage


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Recent RunIIa LQ searches at TevatronRecent RunIIa LQ searches at TevatronRecent RunIIa LQ searches at TevatronRecent RunIIa LQ searches at Tevatron

Channel Lint (pb-

1)Status

SLQ2 pairs ++2q

1050 07 Prel.this talk

LQ3 pairs

2+2b310 07 Sub

LQ2 pairs

2+2qLQ2 + 2+q

300 07Pub.

LQ pairs

2+2q370 06 Pub.

LQ2 pairs

2+2q290 06 Pub.

LQ1 pairs

2e+2qLQ1 pairs e++2q

252 04 Pub.

Channel Lint (pb-

1)Status

VLQ3 pairs2+2b 322 07 Sub

SLQ2 pairs

2+2j198 04 Pub

SLQ2 pairs +2j

198 04 Pub

SLQ1 pairs e+2j 200 04 Pub

SLQ1 pairs e++2j

200 04 Pub

SLQ1 pairs 2+2q

191 03 Pub

Scalar LQ1 pairs : comb. 3 analyses above

~200 05 Pub.

Scalar LQ2 pairs : comb. 2 analyses above

~200 06 Pub.

CDF D0

Sub= submitted Pub. = Published, Prel. = Preliminary

1 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London Beyond the Standard Model Searches...

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