Ph.Gris 1Moriond QCD - March 21st 2011 1

SUSY Searches at

the

TeVatron

Philippe Gris

LPC Clermont-Ferrand -

IN2P3/CNRS

On behalf

of

the

CDF and

DØ

collaborations

•

SUSY in a nutshell•

3rd generation

Squark

searches

•

gaugino

searches•

R-parity

Violating

searches

Ph.Gris 2Moriond QCD - March 21st 2011 2

SUSY in a nutshell

Supersymmetry: space-time

symmetry

bosons <-> fermions

Ph.Gris 3Moriond QCD - March 21st 2011 3

SUSY in a nutshell

Supersymmetry: space-time

symmetry

bosons <-> fermions

g gluino gluon

b Sbottom b quark bottom

t Stop t quark top

1,2

1,2

~

~

~

→

→

→

Ph.Gris 4Moriond QCD - March 21st 2011 4

SUSY in a nutshell

Supersymmetry: space-time

symmetry

bosons <-> fermions

)~,~,~(~,,

)~,~(~,0

4,3,2,1

2,1

HZHZ

HWHW

γχγ

χ

sNeutralino

Charginos

→

→ ±±±±±

Ph.Gris 5Moriond QCD - March 21st 2011 5

SUSY in a nutshell

Supersymmetry: space-time

symmetry

bosons <-> fermions

τμτμ νν ,,,,~

ee Sneutrinos →

Ph.Gris 6Moriond QCD - March 21st 2011 6

SUSY in a nutshell

•

SUSY breaking

If SUSY is

a fundamental

symmetry, it

must be

broken.But the

breaking

mechanism

is

unknown.many

models: –

gravity

mediated: mSUGRA–

gaugino

mediated: GMSB few

parameters–

anomaly

mediated: AMSB–

…

•

R-parity

Rp

=+1 (SM particles), R p

=-1 (SUSY particles)

if Rp

: SUSY particles

produced

by pair.the

Lightest

Supersymmetric

Particle

(LSP) is

stable.

if Rp

: SUSY particles

decay

to SM particles

(small

couplings: λ,λ´,λ´´)

Ph.Gris 7Moriond QCD - March 21st 2011 7

CDF and

DØ

Ph.Gris 8Moriond QCD - March 21st 2011 8

SUSY Searches

at

the

Tevatron

Searches

for3rd generation

squarks

Ph.Gris 9Moriond QCD - March 21st 2011 9

Stop searches: ν~~1 blt →

t1

~t1

~b ETe μ b

LSP ~decay body -3

ν

Signal topology

depends

on• MET• pT

(leptons, jets) with

Δm

ν~~1

mmm t −=Δ

Main background: Z ττ,WW, ttbar

Optimisation of

the

search: Δm ≥

(<) 60

Data MC

∆m>60 GeV 472 513±37

∆m<60 GeV 776 785±57

Phys. Lett. B 696 (2011) 321

Ph.Gris 10Moriond QCD - March 21st 2011 10

Stop searches:

Phys. Rev. Lett. 104 (2010) 251801

Background: •

W/Z+jets,diboson,ttbar•

multijets

(from Data)

Selection:• 2 leptons (e or μ) pT

>20 GeV

|η|<2 (1)• at

least

two

jets ET

>12 GeV• MET>20 GeV• 76<Mℓℓ

<106 Sig(MET)>4• 2 samples

(btagging)

Stop mass

reconstruction

2.7 fb-1

LSP 0

1

~χ

Ph.Gris 11Moriond QCD - March 21st 2011 11

Sbottom

searches:

Phys. Lett. B 693 (2010) 95

Background: •

W/Z+jets,diboson,ttbar•

multijets

(low

MET region-

from

Data)

Selection:• Njets=2 or 3 pT

>20 GeV; angle<165o

• lepton veto• MET>40 GeV• btagging

(NN): at least 2 jets

(msbot,mneutra) Data MC

(130,85) 901 971±52

(240,0) 7 6.9±1.7

Selections

optimized

for two

mass

points

LSP 0

1

~χ

Ph.Gris 12Moriond QCD - March 21st 2011 12

SUSY Searches

at

the

Tevatron

Searches

forgauginos

Ph.Gris 13Moriond QCD - March 21st 2011 13

Search

for trilepton

events

0

21

~~ χχ +→pp

3 leptons+MET

Analysis

strategy:• select μ,e,τ

and

tracks

of

some

quality• leptons have tight

and

loose

categories• apply

cleaning

cuts

Background:• real

leptons (WZ,ZZ,ttbar,WW,Z): fromMC• fakes

(jets faking

e, tracks

faking

μ): from

Data

LSP 0

1

~χ

Ph.Gris 14Moriond QCD - March 21st 2011 14

Search

for trilepton

events

CDF Public Note 9817Phys. Lett. B 680 (2009) 34

Ph.Gris 15Moriond QCD - March 21st 2011 15

Search

for diphoton+MET events

GMSB model, gravitino LSP

Selection:• at

least

two

isolated

photons ET > 25 GeV• no

explicit requirements

for jets and

leptons

Background:• instrumental MET sources (SM γγ, γ+jets, MJ)

(mismeasurements

iao

ET balanced

event)• genuine

MET source (Wγ,W+jets,W/Z+γγ)(real

SM + misID

electrons)Phys. Rev. Lett. 105 (2010) 221802

Ph.Gris 16Moriond QCD - March 21st 2011 16

Search

for leptonic

jets+MET

if M(γD

)≤1 GeV

(light dark

matter) : γD

decays

in jets of

tightly

collimated

particles

with

charged

leptons: the

leptonic

jets.

Data: 21

MC: 36.3±10.4

Selection:• 2 ℓ-jet

candidates (e or μ) required• three

classes: μμ,eμ,ee• MET>30 GeV

Background:• multijet

production• photon production: γ->e+e-

fromData

Phys. Rev. Lett

105 (2010) 211802

Hidden

valley

models

introduce

a new hidden

sector, weakly

coupled

to the

SM. Hidden

valley

models

can

contain

Supersymmetry. The

force carriers in the

hidden

sector

are the

dark

photons γD .

hidden

sectordark

neutralino

(LSP)

Ph.Gris 17Moriond QCD - March 21st 2011 17

SUSY Searches

at

the

Tevatron

Rp

Searches

Ph.Gris 18Moriond QCD - March 21st 2011 18

Search

for tau sneutrino

Background:• Z/γ*-> ττ• dibosons• ttbar• W+jets

Selection:• isolated

e (ET

>30 GeV) and

μ

(pT

>25 GeV)• no

jets with

pT

>25 GeV• MET>20 GeV

if 0.7<∆Φ(MET,μ)<2.3

Data: 414

MC: 410±38

Systematics:• lumi

(6.5%)• trigger (0.5%)• cross sections (2.7-15%)•PDF (0.4-0.6%)

Phys. Rev. Lett. 105 (2010) 191802

λ’311 λ321

τ

Indirect 2σ

bound

(M=100 GeV):λ’

311

λ321 ≤

2.1 10-8

λ’311

≤

0.12

λ321

≤

0.07

Ph.Gris 19Moriond QCD - March 21st 2011 19

Search

for 3-jet resonance

(gluinos)

Selection:• no

MET: MET ≤50 GeV• Njets≥6 (pT

≥15 GeV), 1≤Nvert

≤4• ∑pT

(jets)≥

250 GeV

(6 highest

pT

)• diagonal cut: ∑pT

(3 jets)-M(3jets)>offset(adjusted

for each

mass)

CDF Public Note 10256

Landau shape

from

5-jets events

Largest

excess

around

the

top mass

Ph.Gris 20Moriond QCD - March 21st 2011 20

Conclusions and

outlook

•

Extensive searches

for SUSY signals

have been

performed

at the

TeVatron. No evidence

found

yet.

•

All

CDF and

DØ

results are available:http://www-cdf.fnal.gov/physics/exotic/exotic.htmlhttp://www-d0.fnal.gov/Run2Physics/np/

•

The

LHC has

started, has

already

surpassed

some

of

our

results (squarks

and

gluino), and

will

supersede

our

research

soon.

•

But until

then, we

still

have some

original work

in progress.

•

New exciting

results

should

appear

shortly

!

Ph.Gris 21Moriond QCD - March 21st 2011 21

Backup

Ph.Gris 22Moriond QCD - March 21st 2011 22

Ph.Gris 23Moriond QCD - March 21st 2011 23

Ph.Gris 24Moriond QCD - March 21st 2011 24

Object

definitions

Jets:•

from

energy

deposition

in the

calorimeter

(cone

algorithm

ΔR=0.5)•Selection

cuts

to suppress

background(noise,…)•Coarse

hadronic

fraction•Em

fraction•

tracks

pt sum associated

with

the

jet coming

from

the

PV0•

non-linearities

of

the

calorimeter

response, non instrumental response, noise: corrected

by JES -> relative uncertainty

on the

jet calibration: ≈7% for 20< pT

> 250 GeV• jet momentum resolution: pT

=50 GeV• σ(pT

)/pT

≈

13% (CC)•σ(pT

)/pT

≈

12% (EC)

MET:•Computed

from

the

vector

sum

of

the

transverse energies

of

all

calorimeter

cells

surviving

noise suppression algorihtms

-> raw

MET•After

EM and

JES correction: raw

Met is

adjusted

through

vector

substraction

(hadronic

part from

clustered

jets)-> calorimeter

MET• muons are identified

and

subtracted

-> MET

Electron/photon:•Localized

energy

deposits

in the

EM calorimeter

(clusters)•large EM fraction•Longitudinal and

lateral

shower

profiles of

EM cluster compatible with

those

of

an electron

(photon)•Isolated

cluster•Electron: track

match•Electron: likelihood

(7 variables)•Energy

resolution:•CC: σ(E)/E≈(15/√E+4)%•EC: σ(E)/E≈(21/√E+4)%

Muon:•Identification based

on a matches between

charged

particles

found

in the

central tracking

system

and

trajectories

reconstructed

in the

muno

systems.•Consistency

with

the

primary

vertex•Isolated

object

(track-based

and

calorimeter-

based)•

99% of

muons originating

in hadronic

jet decays

are rejected.•87% efficiency

for a muon coming

from

a top quark decay

Ph.Gris 25Moriond QCD - March 21st 2011 25

Stop searches

L=1 fb-1 9000 evts

1000 evts

Stop decays

Assumptions

for stop searches

at

the

TeVatron:

+LEP2 constraints

~~ : 4

... ,~~ ,~~ ,~~ : 3

,...~~ ,~~,~~ :2

011

110

11

110

110

11

χ

ννχ

χχχ

fbft-body

lbtbltbWt-body

btcttt-body

′→

→→→

→→→ +

toptparity mmR <1~

~~ : 4

~~ ,~~ : 3

~~ :2

011

10

11

011

χ

νχ

χ

fbft-body

bltbWt-body

ct-body

′→

→→

→

60 80 100 120 140 160 180 200-110

1

10

210

)2 (GeV/c1

t~m

xBR

(pb)

σ

Prospino2

)1

t~=m

rfμNLO(CTEQ6.1M -

PDF+scales uncertainties

Ph.Gris 26Moriond QCD - March 21st 2011 26

Stop searches: 011

~~ χct →

Trigger: jets+MET

Background: •

W/Z+jets•

WW, ZZ, WZ•

tt•

multijets

(from

Data)

Preselection

criteria:•MET>50 GeV•≥

2 jets (1 central) ET

>25 GeV•Leading

jet : ET

>35 GeV•at

least

one

HF tagged

jet

Signature: 2 acoplanar

jets+MET

@95% C.L.

Signal optimization:•exactly

two

jets•∆Φ(MET,TrkMET)<π/2•2 NN (multijet, HF tagging)

CD

F P

ublic N

ote 9834

Ph.Gris 27Moriond QCD - March 21st 2011 27

Search

for gauginos

using

Z+W+MET

e

e

inclusive electron

triggers

2 electrons, 2 jets, MET

Selection:• ET (e,jets)>20 GeV• 2 electrons, njets≥2• MET>40 Gev• 85 < MZ

< 97 GeV• 60 < MW

< 95 GeV

Background:• real

leptons (Z, diboson, ttbar): from

MC• fakes

(jets faking

electrons): from

Data

Data MC

MET>40 GeV 7 6.41±0.94

MET>50 GeV 2 3.76±0.58

MET>60 GeV 1 2.02±0.33

CD

F P

ublic N

ote 9791

Ph.Gris 28Moriond QCD - March 21st 2011 28

Search

for dark

photons

Hidden

valley

models

introduce

a new hidden

sector, weakly

coupled

to the

SM. Hidden

valley

models

can

contain

Supersymmetry. The

force carriers in the

hidden

sector

are the

dark

photons γD .

hidden

sectordark

neutralino

(LSP)

Triggers: high

ET single EM

γD

->e+e-

γD

->μ+μ-

Selection:• at

least

one

photon ET>30 GeV• MET>20 GeV• dark

photon candidates: pairs of

oppositely

close charged

tracks.

Background:• QCD events

with

real

or fake

photons • W->e/μν

plus real

or fake

photons• W->τν->3h+ν

plus real

or fake

photons

Ph

ys. R

ev. L

ett. 103 (20

09) 0

81802

Ph.Gris 29Moriond QCD - March 21st 2011

gluinos

decaying

to sbottoms

•

Light sbottom

(high

tanβ)

•

Signature: 4(b)jets+METTrigger:L1: MET>25 GeVL2: 2 jets ET

> 10 GeVL3: MET> 35 GeV

Background: •W/Z+jets, tt•multijets

Selection

criteria:• MET > 70 GeV• at

least

2 jets ET

≥

25 GeV, ET lead

>35 GeV•At

least

two

jets b-identified• 2 NN used

(depending

on ∆m)

Systematic

uncertainties:•

JES: 15% (MC), 10%(signal) 25%(multijets)

•

Luminosity: 6%•

Btag

efficiency

and

rate (50%)•

mistag

rate (16%)•

Cross sections:11.5%

Ph

ys. R

ev. L

ett. 102 (20

09) 22180

1

LSP 0

1

~χ