J.-F. GrivazSUSY-06 June 16, 20061 Search for Physics Beyond the Standard Model at the TeVatron...

J.-F. Grivaz SUSY-06 June 16, 2006 1

Search for Physics Beyond the Standard Model

at the TeVatron

Jean-François Grivaz(LAL-Orsay)

for the CDF and DØ Collaborations


Beyond the Standard Model:Enlarge the gauge group Z’, W’

(*) Alternative EWSB mechanisms (TC, little Higgs)(*) Relate quarks and leptons Leptoquarks

Extend Poincaré Supersymmetryand include gravitation (Supergravity)

Increase the number of dimensions(*) Repeat the history (compositeness)

(*) = Not covered today (in 30’)

The Standard Model:SU(3)c x SU(2)L x U(1)Y

The Higgs mechanismThree generations of quarks and leptonsThe Poincaré groupIn a 4-dimensional space-time


At the TeVatron:p-pbar collisions at 1.96 TeV c.o.m. energyPeak luminosity: > 1.7 E32 cm-2s-1

Delivered: > 1.5 fb-1

In this talk: 0.2 to 1.1 fb-1

DØ: http://www-d0.fnal.gov/Run2Physics/WWW/results/np.htmCDF: http://www-cdf.fnal.gov/physics/exotic/exotic.html

Main Injector

TevatronDØCDF

Chicago

p source

Booster

Unless there are good reasons, I’ll pick examples in either one.

Still the energy

frontier


New Gauge Bosons


Extra Gauge Bosons

M(Z’-seq.) > 850 GeV(somewhat lower limits in)

(canonical E(6) models)

MT = M(electron-pT,missing-ET)

M(W’-seq.) > 788 GeV

e.g., W’ in L-R models Z’ within E(6) GUTs

Beauchemin


Supersymmetry


SUperSYmmetryAt such a conference, no “What is SUSY ?”, or “Why SUSY ?”

Which SUSY ?

More or less constrained MSSM, à la mSUGRAneutralino-LSPwith or without R-parity violation

Gauge Mediated SUSY Breaking gravitino-LSP and neutralino-NLSP

Anomaly Mediated SUSY Breakingwino-LSP and long-lived chargino

Split SUSYlong-lived gluino


(m)SUGRA

Two main search streams at the Tevatron:

Squarks and gluinos multijets + missing ET• large production cross sections• large experimental backgrounds

Electroweak gauginos with leptonic decays (Trileptons)• low production cross sections• typically low leptonic branching ratios• clean experimental signature

m0 m1/2 tan() A0 sign()


Trileptons• Arise from chargino-neutralino associated production• “Golden” SUSY signature but: - low cross sections ( BR) - soft leptons - taus (at large tan) Needs large integrated luminosity Combine various final states (Also decays via W/Z exchange)

General strategy (similar in CDF and DØ):Two isolated (rather soft) e or Require some Missing ET () channel-dependent cuts (e.g. anti Z, )- An isolated third lepton or track (sensitive to ’s), or- Two same sign leptonsMain backgrounds: DY, WW, WZ, W (+ a bit of bb and mis-ID)

Strologas Hohlfeld


CDF AnalysisLumi(pb-1)

Total predictedBackground

Observd data

ee,e, 710 6.801.00 9

+e/ (low-pT) 310 0.130.03 0

ee+track 610 0.480.07 1

ee + e/ 350 0.170.05 0

+e/ 750 0.640.18 1

e +e/ 750 0.780.15 0

DØ Analysis Lumi (fb-1)

Total predicted Background

Observd data

ee+track 1.2 0.820.66 0

+track 0.3 1.750.57 2

e+track 0.3 0.310.13 0

SS 0.9 1.1 0.4 1

e+track 0.3 0.580.14 0

+track 0.3 0.360.13 1

The results of the various channels are combined, “weighted” according to their sensitivity, with overlaps taken into account.

Cross-section upper limits & mass lower limits within specific models.

Missing ET

in +e/Missing ET pT(3)

in ee+track

…and in the end…


m0 = 60 GeV 2-body decays enhanced ()s mixing on ( sL component) decays to ’s enhanced ()

Models = “favorably tweaked” mSUGRABoth CDF and DØ set ms = mse = ms

m(sl) = m(20) +

only 3-body decays ()s mixing off (no sL component) decays to ’s = to e/ ()

Some work ahead for the TEV-WG…


Generic squarks and gluinos

Strong production ( Large cross sections ) of:• sq-sqbar and sq-sq at least 2 jets + missing ET (sq q) • gl-gl at least 4 jets + missing ET (gl qq)• sq-gl at least 3 jets Cascade decays complicate the picture model needed (mSUGRA)

DØ three analyses optimized for each of these processesreduces QCD to a negligible level

CDF 3-jet analysis optimized mostly for m(sq) m(gl)larger QCD background, estimated from control regions

Main backgrounds:• Instrumental (QCD multijets with fake missing ET)• (W(missed lepton)+) +jets (also from ttbar)• (Z ) +jets (irreducible)

Martinez Bargassa


Main analysis cuts:• Data cleaning• Jet1,2(,3(,4)) pT

• Missing ET • HT = sum of jets pT’s• Lepton veto• Angles (jet,missing ET)

Analyses Background expected

Events observed

DØ 2 jets 4.8 4.5 6

DØ 3 jets 3.9 1.5 4

CDF 3 jets 8.2 2.9 2

DØ 4 jets 10.3 2.4 10

HT225 GeV

(m(gl)=240 GeV)


Mgl > 387 GeV (when Mgl~Msq)Mgl > 241 GeV & Msq > 325 GeV

You have seen or will see other versions of this plot.

CDF vs DØ differences:• 371 vs 310 pb-1

• tan = 5 vs 3 (little impact)• 4 vs. 5 flavors (little impact)Theoretical uncertainty onthe signal cross section:• CDF includes it as a systematic uncertainty in the computation of the cross section limit• DØ reduces instead the theoretical cross section by its uncertainty (more conservative): yellow band…and CDF was a bit lucky.

Some work ahead for the TEV-WG…


stR

StopA light stop can be expected:top-Yukawa impact in RGE First scenario considered by DØ:

(relevant as long as m(st) < m(b)+m(W)+m())(in SUGRA, needs M1 < M2 at GUT scale)

1 c-jet (soft tag)+ missing ET

(optimized for various m(st),m())

Main backgrounds: W/Z+jets

+ Large L-R mixing

stop NLSP and LSPwith stc (FCNC)

m(st) = 130 GeVm() = 50 GeV

Bargassa


Light sneutrino st b l s 2 leptons (+b-jets) + missing ET (s)

(optimized for various m(st),m(s))

Stop exclusion up to m(top)

Second scenario considered by DØ:

e and final states analyzedMain backgrounds: Z at low mass, top at high mass

e analysis: ST=pT(e)+pT()+missing ET

with two signal examples

Stop Bargassa


SbottomA light sbottom can be expected at large tan.DØ searched for sbottom pair production, with sbb

1 b-jet + missing ET (optimized for various m(sb),m())

CDF searched for sbottom fromdecays of pair-produced gluinos: gluino b sb (100%) 3/4 b-jets + missing ET

With 156 pb-1, sbottom masses up to 240 GeV are excluded IF m(gluino) < 280 GeV (and m() = 60 GeV)

m(sb) = 140 GeVm() = 80 GeV

BargassaMartinez


R-parity violationPossible additional terms in the superpotential:

WRPV ijkLiL jE k ijk LiQ jD k ijkU iD jD k

With a term, only RPC pair production, mostly + and 20,

with (cascade) decays to LSP’s followed by RPV decays

e

e-

~

01

~

121

e.g. 4 charged leptons + missing-ET

With a ’i11 term, also resonant production: e.g.


R-parity violation: ijk

DØ: 121, 122, 133 considered Three trilepton searches combined:eee/ 0.90.4 (background /e 0.40.1 (events 0 candidateee 1.31.8 (expected

NN -ID validated with Z

CDF also used clean four-lepton topologies:0 candidate vs 0.0080.004 bg. expected

For 133, ee most powerful at large tan and low m0:

m(10) > 115 GeV

for tan = 20, A0 = 0, 0 and m0 = 100 GeV

Autermann


R-parity violation: ’ijk

DØ: ’211 resonant production

Reconstruct:m(smuon) = m(jj)m(1

0) = m(jj)

No accumulationm(smuon) > 210 to 363 GeV

for’211 > 0.04 to 0.10

(tan=5, A0=0 and < 0)

CDF: ’333 pair production

Look for (e/)(hadrons) +2 jets

2 candidates vs. 2.30.5 bg.

(Also LQ3)

Autermann Martinez


Neutral Long Lived ParticlesDØ search motivated by 3 dimuon events in the NuTeV experiment

Production and decay model: SUSY RPV with a small 122

Look for displaced dimuon vertices (5 to 20 cm)

Calibrate with Ks decays

0 candidate vs. 0.81.6 bg.

Convert NuTeV (p-p at 38 GeV)

to DØ (p-pbar at 1.96 TeV)

(383 pb-1)

Autermann


Charged Massive Stable ParticlesLong-lived charginos are expected in some AMSB models

with a “wino-LSP” (small – 10 mass difference)

They would appear in DØ as slowly-moving muons Make use of the time information of the muon system scintillators

For a 150 GeV chargino:0 candidates for 0.690.05 bg.

Gershtein


Gauge Mediated SUSY BreakingIn GMSB, the LSP is a light gravitino G

A 10 NLSP decays into +G

All backgrounds determined from data(fake photons from dijet events, We+/jet)

pT() > 25 GeV Missing ET > 45 GeV

4 candidates vs. 1.80.7 bg.

“mGMSB Snowmass slope”(N=1, Mm = 2, 0, tan = 15)

Signal dominated by 20 production

m(10) > 120 GeV

Inclusive search by DØ for + missing ET

Gershtein


Stopped GluinosIn “Split-SUSY”, squarks are ultra-heavy long-lived gluinosSuch gluinos form R-hadrons which may stop in the DØ calorimeter.

Backgrounds: beam and cosmic muons, measured

in data.

Strategy: look for a randomly oriented

monojet in an otherwise empty event

(diffractive trigger).

After a while, they decay into a gluon + 10

(q-qbar-10 is also possible).

(A. Arvanitaki et al., arXiv:hep-ph/0506242)

m(10 ) = 50, 90, 200 GeV

Excludes gluino massesup to 300 GeV

Gershtein


Indirect limits from BsSM: Bsis heavily suppressed

910 ) 9. 0 5. 3( ) (

s B BR

SUSY: large enhancement

Huge dimuon backgroundDiscriminate using• Decay length• Isolation• PointingNormalize to B+J/ K+

Limit at 95% C.L (780 pb-1): BR(Bs) < 1. 10-7

1 candidate event selectedin a 60 MeV mass window

vs. 1.40.4 bg. expected

CDF search:

Carena

GeV


Extra Dimensions


Extra-dimensions…come in many flavors: LED, TeV-1, UED, RS

Two classes of models considered:• ADD

2 to 7 large (sub mm) EDsgravity propagates

freely in the bulkKK excitations

cannot be resolved• RS

one 5th (infinite) ED with warped geometry

gravity is localized on a brane other than the SM

KK excitations have spacings of order TeV


Large Extra DimensionsTwo main search streams at the TeVatron:

Real graviton emission Apparent energy-momentum non-conservation in 3D-space “Monojets”Direct sensitivity to the fundamental Planck scale MD

GKK

gq

q GKK

gg

g

V

V

GKKGKK

f

ff

fVirtual graviton exchangeModifies SM cross sectionsSensitivity to the theory cutoff MS

(MS expected to be MD)


MonojetsCDF search in 1.1 fb-1:

Main selection cuts:• one high pT jet ( 150 GeV) (soft jets from ISR are allowed)• isolated lepton veto• Missing ET away from jets• Missing ET 120 GeV

Main background: (Z ) +jetCalibrated with (Zll and Wl) + jet

QCD is negligible

779 events selected819 71 expected

Beauchemin


High pT dileptons & diphotonsDØ search in 200 pb-1 combines ee and to maximize the sensitivity

Still world tightest limits:MS > 1.36 TeV

MS >1.43 TeV w/DØ@Run Iin the GRW formalism

Fit of Data to SM+QCD+LED(MS)


Randall – Sundrum gravitonsHere too, most of the sensitivity is in diphotons (BR = 2ee)

DØ combined ee + as for the LED search doesn’t add much

Two model parameters:Mass and coupling (/MPl)

For /MPl = 0.1: M 785 GeV


Looking for the unexpected


Signature based searches

+ X in 0.7 to 1 fb-1

X=e 2 vs. 4.50.8X= 0 vs. 0.50.1X= 4 vs. 1.90.6

l + Missing ET in 0.3 fb-1

l=e 25 vs. 19.83.2l= 18 vs. 15.32.2

(CDF Run I excess not confirmed)

(Also multileptons + photon)

CDF:

Goncharov


Final remarks

With a steadily improving collider performance there are still a number of years and fb–1 ahead of us

for frontier physics at the TeVatron.

CDF and DØ have now begun to explore clearly virgin territories.

Already 1.3 fb-1 on tape, only partially deciphered Expect many new results in the coming months


Back-up Slides




~~ 0

1ct

~~ /

1

bt

'~~ 0

1ffbt

(tree level)

(loop)

Stop decays in mSUGRA

m0 = 200 to 600 GeV (50 GeV step)

m½ = 110 to 180 GeV (10 GeV step)A0 = –500 to –1000 GeV (100 GeV step)

tan = 3 and 10 to 50 (10 step)Both signs of

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J.-F. GrivazSUSY-06 June 16, 20061 Search for Physics Beyond the Standard Model at the TeVatron...

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