14.-18.4.2004 1

Tibor KurčaIPN Lyon

DIS 2004Štrbské Pleso, Slovakia

14.-18. 4. 2004

Recent Results of SUSY Searches at the Tevatron Collider

On behalf of CDF & D0 collaborations

14.-18.4.2004 DIS 2004 Tibor Kurca 2

Tevatron and CDF & D0 detectors upgrades Supersymmetry searches Direct:

* in mSUGRA: 3-leptons + mET (charginos, neutralinos)

jets + mET (squarks, gluinos) * in mGMSB:

2-photons + mET (charginos, neutralinos)

Indirect: Rare B-meson decays (lightest Higgs)

Summary

Outline

14.-18.4.2004 DIS 2004 Tibor Kurca 3

Tevatron Upgrade - RUN II

Higher energy:√s = 1.8 TeV 1.96 TeV

Higher cross sections (30-40 % for SUSY)

More(anti)protons/bunch

(New Main Injector & Recycler)

More bunches: 6x6 36x36 bunches (3.5 s 396 ns)

Higher luminosity Run I : 2x1031 cm-

2s-1

Run II : 2.9x1032 cm-2s-1

Chicago

Tevatron

Main Injector & Recycler

DØCDF

p source

14.-18.4.2004 DIS 2004 Tibor Kurca 4

D0 Detector – Run II

Muon forward chamber 2

Calorimeter electronics

Trigger system

DAQ system

Solenoid (2 T)

Central tracker (SciFi) 1.7 L1

Silicon vertex detector 3 L1

Preshower – Central & Forward

14.-18.4.2004 DIS 2004 Tibor Kurca 5

CDF Detector – Run II New Si Tracker:

• ||< 2; 7-8 layers Central Drift

Chamber: 1.0; 96 layers

Solenoid/ Time of Flight

150 ps /150 cm Muon Drift

Chambers Muon Scintil.

Counters

extended coverage

||= 1 Forward

Calorimeter

1.1 3.5

Trigger :• COT tracks at L1• Silicon tracks at L2

DAQ

14.-18.4.2004 DIS 2004 Tibor Kurca 6

Run II Data Taking Presented analyses are based on data taken before Sept 2003

All results are preliminary !

Sept 2003

Physics Analysis Sample ∫ℒ dt 200pb-1

14.-18.4.2004 DIS 2004 Tibor Kurca 7

SUSY Particles Spectrum

)1(R )23(

P

SLB Rp-conservation produced in pairs

existence of stable LSP

14.-18.4.2004 DIS 2004 Tibor Kurca 8

Trileptons in mSUGRA 3-leptons (isolated) final state – « gold plated channel »

Challenges: - low x-section (EW-production) - rather soft leptons !

Background: W+Z ℓ ℓ ℓmSUGRA mass assumptions:

Search in 3 channels:• 2e + lepton• e + (+lepton) combined results higher sensitivity• 2 LS

mmm 2 01

021

mmm 02

, ~ 1

14.-18.4.2004 DIS 2004 Tibor Kurca 9

mSUGRA Trileptons: 2e + ℓ (1) Background rejection

Z: 15<Mee<60 GeV

(ee) <2.8

We(+): 1 hit in silicon or

tighter e-likelihood

jets: veto jets ET>80 GeV

scaled mET > 20 GeV

Drell-Yan: mET>20 GeV

(e,mET)>0.4

‘Wannabe’ signal

ℒ dt = 17511/pb

14.-18.4.2004 DIS 2004 Tibor Kurca 10

mSUGRA Trileptons: 2e + ℓ (2)

2 electrons, track matched: pT > 12 (8) GeV, 1.1 (3.0)

• mET > 20 GeV• 3rd lepton isolated high-quality track

• Final cut: mET pT(track) > 250 GeV

(signal) = 2 – 3 %

14.-18.4.2004 DIS 2004 Tibor Kurca 11

mSUGRA Trileptons: 2e + ℓ (3)

expected signal events 0.8 – 1.6 ; tan =3, m =(100-115)GeV expected bgr 0.3 + 0.4 – 0.3 (Zee, WWe e; limited MC statistics) 1 event observed : pT1=33.3, pT2=25.7, pTtrack=8.6

mET=52.1 GeV

14.-18.4.2004 DIS 2004 Tibor Kurca 12

mSUGRA Trileptons: e + (+ ℓ) (1)

Selection cuts:

good e , with isolated, matching tracks: pTe>12, pT>8 GeV; - also calorimeter isolation

mET > 15 GeV

minimal transversal mass: 15<minMT(e, )<80 GeV (Z/*, WW cut)

no dileptons with masses around MZ veto 70-110 GeV, (, ) < 2.5; (,e) > 0.3

jet veto : pT> 60 GeV (1-jet events) (anti tt) pT1 > 40 , pT2 >30 GeV (2 jets)

anti -conversion cut: silicon (SMT) hits 3 for e-track (W)

ℒ dt =

15810/pb

14.-18.4.2004 DIS 2004 Tibor Kurca 13

mSUGRA Trileptons: e + (+ ℓ) (2)

2 subselections: (a) imbalance between pTe, pT and MET: ( for e + , 3rd ℓ missing ! anti WW cut)

(b) 3rd lepton isolated high-quality track pT>3 GeV ( hollow cone, track from the same vtx as other 2, CFT hits..)

most of the remaining bgr ↘… but also signal ↘ Results:

expected signal events 0 – 0.9 ; tan =3, m =(97-114), m° =(57-67) expected bgr : (a) 2.87 0.36 1 event observed (Z/*->, WW,W+jets/ ) (b) 0.54 0.24 no event observed

GeV 6Empp TTeT

±

14.-18.4.2004 DIS 2004 Tibor Kurca 14

Like-Sign Dimuon Channel (1)

Idea: 3ℓ 2LS-leptons…. profit from increased acceptance, while reducing bgr

Challenge: modelling bgr

tt, W+jets, WZ, ZZ Monte Carlo - taken from data

Selection Cuts: 2 track-matched, isolated like-sign , (, )<2.7 pT1 > 11 , pT2 > 5 GeV, mET > 15 GeV topology to kill bb: if pT2 < 11 GeV (jet,mET) < 2.4; min(mET, )>0.5, max(mET, )<2.4, mass cuts to kill Z: OS - M(, )<70 or M(, )>110 GeV LS - M(, )<80 GeV (avoid sign flip)

c/cbb

ℒ dt = 14710/pb

14.-18.4.2004 DIS 2004 Tibor Kurca 15

mSUGRA LS Dimuon Channel (2)

Data points: M(,) – isolated LS

Shaded histogram: remaining bgr estimated from nearly-isolated LS data

Results - events: expected signal : 0 – 0.4; (tan =3, m =(97-114), m°=(57,67) )

expected bgr: 0.13 0.04 (bb, WZ, ZZ, Z)

observed: 1 event pT1=29.1, pT2=13.8, LSmass=37.8, mET=33.5GeV, =1.55

±

14.-18.4.2004 DIS 2004 Tibor Kurca 16

SUSY Trileptons – Combined Result (1)

mSUGRA : tan =3, >0, A0=0, m0=(72,88), m½=(165,185)

m m° 2m° 2e + ℓ e + (+ ℓ ) combined using Likelihood Ratio Method

2 LS signal overlap 15 % (5%) between e++ℓ (e+) e+e+ℓ ,

negligible for LS-dimuon analysis

overlap event assigned to channel with the highest S/B

correlated errors taken into account (main ℒ uncertainty)

±1 12

14.-18.4.2004 DIS 2004 Tibor Kurca 17

SUSY Trileptons – Combined Result (2)

significant improvement of Run I limit

not reaching mSUGRA prediction yet … constrain more generic SUSY models with compatible mass hierarchies

14.-18.4.2004 DIS 2004 Tibor Kurca 18

Squarks & Gluinos Search in mSUGRA

Squarks, gluinos pair production dominates (if light enough…)

- consider only 1st & 2nd families with degenerate masses

- decay chains depend on mass relations

- general event signature: n-jets + MET +m-leptons

Have a look at :

production & 2-body decays dominate

Background: QCD, W/Z+jets

g~q~,g~q~ ,q~q~ ,g~g~ ,q~q~ pp

mm g~ q~

0q q~

qq g~ ... 0

q~q~

Signature: 2 acoplanar jets + mET

14.-18.4.2004 DIS 2004 Tibor Kurca 19

• Jets + Missing ET Trigger (L2, L3) from April 2003

2 jets (cone 0.5) in acoplanar topology

pT1 60, pT2 50 GeV, det1 0.8 - SM, QCD bgr

not EM-object –jet1,jet2 (emf<0.95)

no EM-object with pT>10 GeV W/Z+jets

no isolated with pT>10 GeV

• anti -wrong vertex, -cosmics (cpf>0.05)

mET 60 GeV QCD (moderate MET/correlated with jets) 30 (mET,jet) 165

Final cuts: mET 175 GeV, HT(=Etjets) 275 GeV (optimized for m½=130 GeV )

Squarks & Gluinos – Event Selection

Data : ℒ dt = 85 pb-1

14.-18.4.2004 DIS 2004 Tibor Kurca 20

Squarks & Gluinos Search : Results (2)

mET > 175 GeVHT > 275 GeVObserved 4 events

Expected 2.7 ± 0.95

14.-18.4.2004 DIS 2004 Tibor Kurca 21

Squarks & Gluinos Search: Results (1)

observed 4 events expected 2.7 0.95 Systematics• luminosity: 6.5 %• cross-sections: 8% SM bgr; 10% signal (from Prospino)• jet energy scales (data & MC): +77% -43% SM background +20% -15% signal efficiency

14.-18.4.2004 DIS 2004 Tibor Kurca 22

Signal x-section: PYTHIA (LO) + k-factors PROSPINO (NLO)

mSUGRA parameters: m0 = 25 GeV, A0 = 0, tan =3, <0 m½ = 100 - 140 GeV scan in 5 GeV steps

Mass limits: Msquark > 292 GeV, Mgluino > 333 GeV

Squarks & Gluinos Mass Limits

14.-18.4.2004 DIS 2004 Tibor Kurca 23

Pairs production - large tan 3rd generation sparticles could be light due to large mixing

Gluino production

Sbottom Quarks Production @Tevatron

ggpp ~~

b~bg~mm 1

g~b~

bbpp ~~11

mm q~b~

1

14.-18.4.2004 DIS 2004 Tibor Kurca 24

4 bjets + MET

Background: -QCD, Top, W/Z+jets

Preselection cuts: Signal cuts: 3 jets 15 GeV, < 2 mET > 50 GeV mET > 35 GeV 1 b-tag svx lepton veto (EW bgr) 2 b-tags svx (mET,jets) (QCD bgr)

Assuming:

Btag Observed evts Expected Bgr Expected Signal=================================================Single 4 5.6 1.4 10.6 1.7 Double 1 0.5 0.1 4.4 0.9

Sbottom Quarks from Gluinos

) )( ( ) )( ( ~~ ~~~~ 0

1

0

111 bbbbbbbbgg

bb

GeV60mGeV160mGeV 220m , , ~b~g~

0

11

ℒ dt = 38.4/pb

14.-18.4.2004 DIS 2004 Tibor Kurca 25

Sbottom & Gluino Limits

GeV60mGeV60mm , ~b~g~

0

11

GeV500mq~

14.-18.4.2004 DIS 2004 Tibor Kurca 26

Gauge Mediated SUSY Breaking

SUSY breaking at a scale ~10-100 TeV (<< GUT)

mediated by new gauge fields – « messengers »

LSP is gravitino

- very light M( ) < 1 keV

if NLSP is neutralino:

( also possible)

Exp. Signature: 2 photons + mET

- Assume prompt NLSP decay photons pointing to interaction vtx

G~~0

1

gauginosmostlypp

CDF Run 1

GZ ~~0

1

G~

XGGX ~~ ~~ 0

1

0

1

14.-18.4.2004 DIS 2004 Tibor Kurca 27

mGMSB 2 +mET search : Analysis

Background: 1. fake mET - mismeasured jets, vtx

2. real mET - lost e-track, fake

W e (dominant), Wj e j, Z, WW, WZ, top

Event selection: 2 isolated photons ET> 20 GeV, det,

no matching tracks, no tracks in hollow cone (0.05, 0.4) pT < 2 GeV

- topology : (mET,jet1) < 2.5

(mET, ) > 0.5

- optimized mET > 40 GeV

Signal: looking for excess in tails

of mET distribution

mET (GeV)

14.-18.4.2004 DIS 2004 Tibor Kurca 28

mGMSB 2 +mET search : Results

Observed rates consistent with SM

New limits:

Errors: reco eff. 5%

MC-accept. 6%, 6.5%ℒ

• mGMSB parameters

- scale of SUSY breaking

Mm=2 - messenger mass scale

tan = 5 - vev’s ratio

> 0 – sign of higgsino mass term

GeV 180 )m( GeV, 105 )m( TeV, 7.78 1

0

1

(TeV)

ℒ dt = 18512/pb

95% CL

World’s best !

14.-18.4.2004 DIS 2004 Tibor Kurca 29

mGMSB 2 +mET : CDF Results

Event selection: 2 isolated photons ET> 13 GeV, det, mET > 25 GeV Expected events: bgr 2 ± 1 ± 1; signal 6.6 2 events found Mass limit : tan =15, >0, M=2, N5 =1

GeV 113 )m( 1

(TeV)

ℒ dt = 84/pb

14.-18.4.2004 DIS 2004 Tibor Kurca 30

Rare B-meson Decays – Indirect SUSY Search

• SM prediction:

• FCNC decay - very sensitive probe beyond SM • not observed yet , best limit is CDF-I

• Can be very strongly enhanced for high tan() SUSY complements 3-lepton search

SUSY predicts enhancement by 10-1000 ! … in mSUGRA correlation with a

• search in M=±80 MeV centered on world average Bs(Bd) value

6-E 0.2)B((Br 0

S

)(B B

0

d

0

S

9-E )5.05.3()B((Br 0

S

14.-18.4.2004 DIS 2004 Tibor Kurca 31

Rare B-meson Decays: Results

• expected events: 1.05 ± 0.30 … Bs

1.07 ± 0.31 … Bd

1.75 ± 0.34 … combined• found 1 event : M() = 5.295 GeV … in both windows

Limits @ 90% CL :

•

… 3x better than Run I

• … BELLE@LP03 1.6E-7

ℒ dt =

171/pb

7-E 8.5)B((Br 0

S

7-E 5.1)B((Br 0

d

14.-18.4.2004 DIS 2004 Tibor Kurca 32

Summary Presented results based on ≤ 185ℒ /pb Tevatron experiments are exploring « Terra Incognita » limits extended beyond Run I : - 3ℓ + mET - jets, b-jets + mET - GMSB 2 + mET Many analyses in progress, first Run II papers coming soon Tevatron performance improving end of 2004 on tape ~ 0.5 /fb Better optimized analyses higher sensitivity to signal Excellent opportunity for exciting physics at the highest energy frontier

Hic Sunt Gluinos

14.-18.4.2004 DIS 2004 Tibor Kurca 33

Luminosity Prospects

36×36 bunches396 ns bunch crossing

design: challengingbase: conservative

0

10

20

30

40

50

60

70

80

90

11/23/03 12/21/03 1/18/04 2/15/04 3/14/04

Inte

gra

ted

Lu

min

osity (

pb

-1)

Meas

Design

Base

FY’04 Integrated Luminosity

11/23/03 1/18/04 3/14/04

Measured luminosity

12 pb-1 / week is also above the design projection

Start of Fiscal Year

Inte

gra

ted

Lu

min

osi

ty (

fb-1)