Search For New Physics at the TeVatron

J.-F. Grivaz Euro-GDR 25-November-2004 1

Search For New Physics at the TeVatron

Jean-François Grivaz

LAL-Orsay

http://www-cdf.fnal.gov/physics/exotic/exotic.htmlhttp://www-d0.fnal.gov/Run2Physics/WWW/results.htm

http://www-cdf.fnal.gov/physics/exotic/exotic.html

http://www-d0.fnal.gov/Run2Physics/WWW/results.htm

http://www-d0.fnal.gov/Run2Physics/WWW/results.htm


The Tevatron at Run II

• New Main Injector + Recycler

• Higher energy (1.96 TeV vs 1.8 TeV) => Higher cross sections (~30% for the top)

• Higher antiproton intensity 6x6 36x36 bunches (3.5 s 396 ns) antiproton “recycler” => Higher luminosity

Chicago

Tevatron

Main Injector & Recycler

DØCDF

p source


Luminosity performance

• Peak luminosity: 4 - 8 1031 cm-2 s-1

• Weekly delivered: 8 - 16 pb-1

• Data taking efficiency: 80 - 90%

Physics quality data: up to 350 pb-1 analyzed as of ICHEP04

In 2004:

1032


Searches for New PhenomenaSupersymmetry: (m)SUGRA, GMSBExtra Dimensions: large, warpedExtended Gauge Theories: Z’Higgs bosons: SUSY, SM

In back-up slides: RPV, leptoquarks, excited leptons, doubly-charged HiggsesNot covered : TeV–1 ED, Technicolor, Little Higgs but same signatures as e.g., LED, SM-Higgs, RS-gravitonsReal exotics (e.g. monopoles)


Supersymmetry


(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 (I)

• 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)

DØ analysis based on 147 249 pb1

Combines eel, el, l and same sign dimuon final statesAddresses “just beyond LEP” mSUGRA with low mass sleptons


Trileptons (II)Two isolated (rather soft) e or Require some Missing ET

channel-dependent cuts (e.g. anti Z)- Two same sign muons, or- An isolated third track (no e or ID)Main backgrounds: WW, WZ, W, a bit of bb Altogether: 3 events observed vs 2.9 0.8 expected


Trileptons (III)

Substantial improvement wrt Run I: m() 97 GeV for m(slepton) m()

Should soon probe virgin mSUGRA territory


Stop and sbottomCDF has searched for charged massive particles in 53 pb1 • appear as slow moving (TOF) high pT muons• result interpreted for (meta)stable stop m(stop) 108 GeV (isolated) or 95 GeV (non-isolated)

CDF has searched for sbottoms in gluino decays (156 pb1)• assumes sb1 much lighter than all other squarks (large tan)• gluino sb1 b 4 b-jets + Missing ET for gluino pairs• the selection requires at least one b-tag, no isolated lepton

With 2 b-tags: 4 vs 2.6 0.7 expected


Generic squarks (I)Strong production of:• sq-sqbar• sq-sq• sq-gl• gl-gl

In 85 pb1, DØ has searchedalong the

“minimum sq-mass line” of mSUGRA:

very low m0 (25 GeV),(tan = 3, A0 = 0, 0),

scan over m1/2

Mostly sq-sqbar with sq q Acoplanar jets + Missing ET


QCD

Generic squarks (II)

Main selection cuts:• at least two high pT jets• isolated lepton veto• Missing ET should not be along or opposite to a jet• Sum of jet pT 275 GeV• Missing ET 175 GeV

Main backgrounds left:• (Z ) + jets• (W ) + jetsQCD negligible

4 events selectedvs

2.7 +2.3/1.5

expected


Generic squarks (III)Slight improvement over CDF-Run Ialong that “minimum sq-mass line”:(msq 292 GeV and mgl 333 GeV)

How relevant are the Tevatronresults on squarks and gluinos ?

LEP slepton and chargino limits much tighter constraintson m0 and m1/2 within mSUGRA (or even MSSM with unification)

The Tevatron should consider models with smaller M3/M2 ratios:not unnatural in GUTs (e.g. M3/M2 ~ 1 if SUSY breaking by a 75)or in some string inspired models


GMSB with NLSP (I)

Photon = electron without track• Photon ET 13 / 20 GeV• Missing ET > 45 / 40 GeV• Mild topological cuts

Main backgrounds:• EM-jets (or real QCD photons) + fake Missing ET• electron + photon + real Missing ETAll determined from the data

Inclusive search for Missing ET

by both CDF / DØ

CDF : 0 vs 0.3 0.1 expectedDØ : 2 vs 3.7 0.6 expected

+ gravitinoRemember the CDF ee + Missing ET event ?…


GMSB with NLSP (II)

Interpretation within mGMSB with:• N = 1• Mmessenger = 2, • 0, • tan = 15 (aka “Snowmass slope”)

Signal dominated by chargino-neutralino production

World best limit:m 108 GeV (DØ)

263 pb-1

(Also 93 GeV (CDF))


“Superjets” ?

CDF @ Run I observed an excess of W + 2/3 jet eventswith 1 jet “double-tagged”

(Secondary vertex + Soft lepton)13 vs 4.4 0.6 expected

An interpretation in terms oflight sbottom + RPV ()

has been suggested (not by CDF)

DØ has searched for such an anomaly in 150 pb-1 of Run II dataand did not find any.

Let’s wait and see what CDF will find…


Bs In SM, tiny BR ~ 3.5 109 (and 25 times smaller for Bd)

But in SUSY, a (tan)6 factor could lead to an enhancement by as much as three orders of magnitude

BR limits (95% CL): 5.0 10-7 (DØ 240pb-1) and 7.5 10-7 (CDF 171 pb-1)

Close to getting relevant

Select dimuons originating from displaced vertices, and look inside a mass window:


Extra Dimensions


Models of Extra DimensionsTwo classes of models considered:

• ADD2 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)


MonojetsDØ search in 85 pb-1:

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

Main background: (Z ) +jetQCD is negligible

63 events selected100 +51/-32 expected

Large error from Jet Energy Scale(Updated result coming soon)

QCD


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

World tightest limits:MS > 1.36 TeV

MS >1.43 TeV w/DØ@Run I

in the GRW formalism

Also 1.1 TeV:from CDF in dielectrons with 200 pb-1

from DØ in dimuons with 250 pb-1

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


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

DØ Run II Preliminary

DØ uses the sameee + data set as for the LED search

300 GeV RS-graviton

Two model parameters:Mass and coupling (/MPl)

For /MPl = 0.1: M 785 GeV

Also 690 GeV from CDF in diphotons with 345 pb-1


Z’


Z’ in dielectrons

DØ Run II Preliminary

600 GeV Z’

Now select only electron pairs (much reduced QCD background)

Limits for SM-like Z’and various E6 models

For an SM-like Z’: M 780 GeV

Also M > 750 GeV from CDF (200 pb-1)


Z’ in dimuons

For an SM-like Z’: M 735 GeV

Also M 680 GeV from DØ (250 pb–1)

Z’ limits in various E6 models

Dimuons vs. dielectrons: lower background but worse resolution

Combining ee and : M (SM-like Z’) 815 GeV (CDF)


Z’ in CDF in 195 pb-1

4 events(eh,h,hh)vs2.8 0.5expected


Higgs bosons


SUSY-Higgs @ large tanHbb coupling enhanced

DØ search for 3b jets (130 pb-1)


SM Higgs boson searchesLEP indirect: MH < 260 GeVLEP direct: MH > 114 GeV Hint at 115 GeV

MH < 130 GeV: Hbbgg H bb hopeless (H maybe)H(W l) and H(Z ll/): best processesHbb OK for SUSY @ large tanHtt maybe

MH >150 GeV: H WW*gg H (W l)(W* l): best process Also (H WW*)(W l / Z ll)


High mass: HWW

DØ search in the ee, e and + Missing ET final states

The WW background is reduced using the spin correlations:

smaller ll angle in the Higgs signal

2 ee events vs 2.7 0.4 expected 2 e events vs 3.1 0.3 expected5 events vs 5.3 0.6 expected

(200 pb–1)

(147 – 177 pb–1)


Low mass: (Wl)(Hbb)CDF search in 162 pb–1: e/ + Missing ET + 2jets ( 1 b-tag)

Similar DØ search(174 pb–1 - e only)

with 2 b-tags

Still a long wayto go…


Are we going there ?Updated signal and background

cross sectionsFull detector simulation

+ established analysis techniques + “reasonable extrapolations”

+ Signal shape (vs. mass window)(but no systematics…)

If we are lucky: 3 evidenceIf not…: 95% CL exclusion of the MSSM range

LHCNow


Final remarks

With a data sample at least 20 to 40 times larger than at Run I, collected at higher energy with improved detectors,

there is a lot of beautiful (but difficult) physics to be done:

• W and top masses, top properties, single top production• B physics: Bs mixing, rare Bs decays, Bs and b lifetimes• Exploration of new territory (SUSY, LED…): we may be lucky…

already well underwayinteraction with theorists welcome !

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.

The Higgs is not the whole story…


Back-up Slides


The CDF and DØ upgrades

• New tracking: silicon and fibers in 2T magnetic field• Upgraded muon system• New DAQ and new trigger (commissioning displaced track)

• New silicon and drift chamber• Upgraded calorimeter (plug) and muon system• New DAQ and new trigger, (displaced track trigger)

… and new software (C++, OO)


The Run II Menu

CDF/D02 fb-1goal!

With 2 fb-1:

•Top mass to 3 GeV•W mass to 30 MeV•Bs mixing to 20 ps-1

•Exclude mH = 115 GeV

And much more…• High pT jets• LED to 2 TeV• SUSY

And beyond:


RPV with ijkLiLjLk coupling (I)DØ has searched for multilpeton final states arising from

SUSY particle pair production with R-parity violating decays of two neutralino LSP’s

in the regime where is small enough so that only the LSP has

an RPV decay, and large enough for its lifetime to be negligible.

The couplings considered were121 eeee, eee or ee + 122 , e or ee +

Three isolated (rather soft) e or Require some Missing ET

channel-dependent cuts (e.g. anti Z)


RPV with ijkLiLjLk coupling (II)

eee/

121: 0 vs 0.5 0.4 expected(238 pb-1)

m 200 GeV

122: 2 vs 0.6 1.9 expected(163 pb-1)

A search has also been performedfor the 133 coupling, in the eeXfinal state, with hadrons +

(199 pb-1)

Resonant single slepton or sneutrinoproduction via a 211 RPV couplinghas also been investigated (154 pb-1)


LeptoquarksLQ lq (BR = ) or LQ q (BR = 1 – )

Pair produced llqq, lqq or qq final states

2nd generation LQ in qq (CDF – 200 pb-1):

2 muons, 2 jets, Z-veto

M 241 GeV

2 events vs 3.2 1.2 expected


1st generation Leptoquarks (I)DØ analysis performed in the eeqq and eqq channels (175 pb-1)

2 electrons, 2 jets and Z-veto 1 electron, missing ET and W-veto

ST = ET(e1)+ET(e2)+ET(j1)+ET(j2)

(After all other cuts)

ST = ET(e1)+MET+ET(j1)+ET(j2)

(Before W-veto)

0 events vs 0.4 0.1 expected 2 events vs 4.7 0.9 expected


1st generation Leptoquarks (II)

M 238 GeV ( = 1)M 213 GeV ( = 0.5) (DØ – 175 pb-1)

Also CDF with 200 pb-1:M 230 GeV ( = 1)M 176 GeV ( = 0.5 not combined)


Leptoquarks in the qq channelTopology = Acoplanar jets + Missing ET

Large backgrounds from QCD multijetsand from SM processes (Z jets)

124 events vs 118.5 14.5 expectedAlso DØ with 85 pb-1:

M 109 GeV


Excited electrons

3 events vs 3.0 0.4 expected

CDF search in the ee final state (200 pb-1)

(main background = Z)

Z - veto


Doubly-charged Higgs BosonsDoubly charged Higgs (from Higgs triplets) are predicted in, e.g., LR-symmetric models

CDF has searched for H

pair production in 240 pb-1

The signature is a pair ofsame sign ee, e or 0 ee events vs 1.5 +0.90.6 expected 0 e events vs 0.4 0.2 expected0 events vs 0.8 +0.50.4 expected

Also DØ in (113 pb-1):M(H

L) > 118 GeVM(H

R) > 98 GeV

Documents

Search For New Physics at the TeVatron