Andrey Loginov - Collider Detector at FermilabDIS 2009, Madrid, Spain, 26-30 April 2009 Andrey Loginov Search for SUSY at the Tevatron Why Standard Model (SM) †The SM describes data

DIS 2009, Madrid, Spain, 26-30 April 2009 Andrey Loginov Search for SUSY at the Tevatron

Search for SUSY at the Tevatron

Andrey Loginov

Yale University

DIS 2009, Madrid, Spain, 26-30 April 2009

For CDF and DØ Collaborations

-1-


Why

Standard Model (SM)

• The SM describes data from colliderexperiments very well

• The only particle missing is Higgs boson

– Directly sensitive to ΛUV(unlike other SM particles)

– Enormous quantum corrections:

∆m2H = −|λf |2

8π2 Λ2UV + . . .

• The predicted high energy behavioris unphysical at the TeV scale

• Didn’t predict massive neutrinos

• Cosmology data needs more:Dark Matter Candidate

-2-


Why

Cosmology

• Galaxy Rotation

• Requires massive stable particles

• The theory should

– Describe early Universe physics

– Predict relic density (WMAP data)

-3-


SUSY

• Higgs boson mass quantum corrections

Hf

(a)

S

H(b)

∆m2H = 1

8π2(λS − |λf |2)Λ2UV + . . .

•Q|Boson〉 = |Fermion〉,Q|Fermion〉 = |Boson〉

• R-Parity: PR = (−1)3(B−L)+2s

1 for SM, -1 for superpartners

• R-parity is conserved:

– The SUSY particles produced in pairs

– Dark Matter candidate

• Supersymmetry is broken

• 32 new particles, 105 new parameters2 4 6 8 10 12 14 16 18

Log10(Q/1 GeV)

0

10

20

30

40

50

60

α−1

α1−1

α2−1

α3−1

-4-


SUSYNames Spin PR Gauge Eigenstates Mass Eigenstates

Higgs bosons 0 +1 H0u H0

d H+u H−

d h0 H0 A0 H±

uL uR dL dR (same)

squarks 0 −1 sL sR cL cR (same)

tL tR bL bR t1 t2 b1 b2

eL eR νe (same)

sleptons 0 −1 µL µR νµ (same)

τL τR ντ τ1 τ2 ντ

neutralinos 1/2 −1 B0 W 0 H0u H0

d χ01 χ0

2 χ03 χ0

4

charginos 1/2 −1 W± H+u H−

d χ±1 χ±

2

gluino 1/2 −1 g (same)goldstino

(gravitino)1/2

(3/2)−1 G (same)

-5-


Where: Tevatron

• pp Collisions• √s=1.96 TeV• Lpeak = 3.7×1032 cm−2s−1

Store Number T

otal

Lum

inos

ity (p

b-1)

0

1000

2000

3000

4000

5000

6000

1000 2000 3000 4000 5000 6000

1 4 7 10 1 4 7101 4 7 1 4 7101 7101 4 7101 4 72002 2003 2004 20052006 2007 2008 2009Year

Month

DeliveredTo tape

•>6 fb−1 delivered, >5 fb−1 on tape

• In this talk: up to 4.1 fb−1 results

-6-


Where: CDF and DØ

Calorimeter

Shielding

Toroid

Muon Chambers

Muon Scintillators

η = 0 η = 1

η = 2

[m]

η = 3

–10 –5 0 5 10

–5

0

5

Detectors and identified objects:• Trackers: e, µ, jets• Calorimeters: e, µ, jets, 6ET• Muon Detectors: µ, soft µ′s from jets

-7-


Physics

Data-driven backgrounds are crucial

• Jets misID as leptons

– Isolation etc.

• Fake 6ET (mismeasured jet, lost µ)

Tracking Iso:∑

ptrackT in η − φ

Calorimeter Iso:∑

EtowerT in η − φ

Jet with a displaced vertex:“b-tag”, “HF-jet”

-8-


Physics

• StopTop sample is large and pure, top dileptons are under control

• Sbottom4 b-quarks in the final state

• RPV ντ

Single sparticle production is allowed

• Direct production of the GauginosLighter, EWK production cross sections, leptonic final states

• Squarks and Gluinos:Heavy, but strong production cross-section

• CHAMPs (Charged MAssive Stable Particles)“slow moving muons”

-9-


Physics: Stop

• t → bχ±1 → bχ0

1`ν (mt1< mt)

• on-shell charginos• tt sample: ` 6ET + 2 b − jets

Mass (GeV)t~100 150 200 250 300 350

Even

ts/2

0 G

eV

0

5

10

15

20

25

Mass (GeV)t~100 150 200 250 300 350

Even

ts/2

0 G

eV

0

5

10

15

20

25data

Stop (DIL BR = 0.30)

=172.5 GeV)t

Top (M

Z + Heavy Flavor

Z + Light Flavor

Dibosons

Fakes

=135 GeVt~M=125.8 GeV±χ∼M=58.8 GeV0χ∼M

)-1CDF Run II Preliminary (2.7 fb

Reconstructed Stop Mass, B-Tagged Channel

2) GeV/c1t~M(

135 140 145 150 155 160 165 170 175 180 185

2) G

eV/c

0 1χ∼M

(

45

50

55

60

65

70

75

80

85 2)=125.8 GeV/c±1

χ∼M(b)=1

1±χ∼→1t

~BR(

Observed 95% CL)-1CDF Run II Preliminary (2.7 fb

l)=0.25ν10χ∼→

1±χ∼(2BR

l)=0.50ν10χ∼→

1±χ∼(2BR

l)=1.0ν10χ∼→

1±χ∼(2BR

Excluded by LEP

-10-


Physics: Stop

• t → `bν (mχ±

1> mt)

•DØ ee, eµ• CDF ee, eµ, µµ

DØ: arXiv 0811.0459 (accepted to PLB)

(GeV)TS50 100 150 200 250 300 350

Even

ts /

74 G

eV

-110

1

10

210

50 100 150 200 250 300 350-110

1

10

210

Inst. Bkg.Diboson

ee→ *γZ/ττ → *γZ/

ttDataSignal ASignal B

(f)-1DØ, L = 1 fb

DataSt

(GeV)TS100 150 200 250 300 350 400

Even

ts /

20 G

eV

1

10

210

100 150 200 250 300 350 400

1

10

210Inst. Bkg.Diboson

τ τ->*γZ/tt

DataSignal ASignal B

(f)-1DØ, L = 1 fb

DataSt_new

A/B: m(t, ν) = (140, 110)/(170, 90) GeV

, GeVTE20 40 60 80 100 120 140 160 180 200

# of

eve

nts/

12 G

eV

-210

-110

1

10

210 )µµ+µ, Cut Group c (ee+eTE

-1CDF Run II Preliminary, 1 fb

2)=75 GeV/cν∼)=150, m(t~m(

stop signall+fakesHF(data)Drell-Yandibosontt

data

, GeVTE20 40 60 80 100 120 140 160 180 200

# of

eve

nts/

12 G

eV

-210

-110

1

10

210

]2 [GeV/c t~ M60 80 100 120 140 160 180 200

]2

[GeV

/c ν∼

M

40

50

60

70

80

90

100

110

120

130 bν∼ l → t~Scalar top in the Dilepton Channel:

b

+ M

ν∼

< M

t~ M

AlephL3

OpalLEP

CDF Preliminaryb)=100%ν∼ l→t~ Br (τ,µe,

∑-1Run II, 1 fb

CDF ExpectedCDF Observed

-1DØ Run II 1 fb

]2 [GeV/c t~ M60 80 100 120 140 160 180 200

]2

[GeV

/c ν∼

M

40

50

60

70

80

90

100

110

120

130

Brand new result from CDF!-11-


Physics: Sbottom (from gluino decay)

• g → bb, b → bχ01

• 6ET + 4 b − jets, 2.5 fb−1 (CDF)• 2 NN (small and large ∆m

gb)

• 1 and 2 b-tags samples

NN Output-1.5 -1 -0.5 0 0.5 1 1.5

N-Ev

ents

0

2

4

6

8

10)=315b~)=335, M(g~Signal M(

CDF DataEWK BOSONSTOPMistagsInclusive Multijets

NN Output-1.5 -1 -0.5 0 0.5 1 1.5

N-Ev

ents

0

2

4

6

8

10

CDF Run II Preliminary -1 L dt=2.5 fb∫

Two inclusive b-tags

NN Output-1.5 -1 -0.5 0 0.5 1 1.5

N-Ev

ents

0

2

4

6

8

10)=315b~)=335, M(g~Signal M(

CDF DataEWK BOSONSTOPMistagsInclusive Multijets

NN Output-1.5 -1 -0.5 0 0.5 1 1.5

N-Ev

ents

0

2

4

6

8

10

CDF Run II Preliminary -1 L dt=2.5 fb∫

Two inclusive b-tags

)2Gluino Mass (GeV/c200 250 300 350 400

)2

Sbot

tom

Mas

s (G

eV/c

100

150

200

250

300

350

)2Gluino Mass (GeV/c200 250 300 350 400

)2

Sbot

tom

Mas

s (G

eV/c

100

150

200

250

300

350

CDF Run I excluded

kinem

atica

lly for

bidde

n

1b~

b→ g~

2) = 60 GeV/cχ∼M(2) = 500 GeV/cq~M(

-1Run II 156 pbExcluded Limit

-1DØ Run II 310 pbSbottom Pair ProductionExcluded Limit

)2Gluino Mass (GeV/c200 250 300 350 400

)2

Sbot

tom

Mas

s (G

eV/c

100

150

200

250

300

350CDF Run II Preliminary

-1 L dt=2.5 fb∫Observed 95% CL limitExpected 95% CL limit b (100% BR)b~ → g~

(100% BR)10χ∼ b→ b~

DØ PRL 97 171806 (2006), 310 pb−1

-12-


Physics: RPV ντ

• CDF @ 1 fb−1: eµ, µτ ,eτ•DØ @ 4.1 fb−1: eµ

(GeV)µeM0 50 100 150 200 250 300

Even

ts/1

0 G

eV

-110

1

10

0 50 100 150 200 250 300-110

1

10

DATA

*γZ/

diboson

ttbar

γw+jet/

= 100 GeV)τν∼

signal (M

preliminary-1DØ, 3.1 fb

W∆L=1 = 12λ

ijkLiLjek + λ′ijkLiQjdk + µ′iLiHu

)2 (GeV/cµInvariant Mass of e100 200 300 400 500 600 700

)2Ev

ents

/(10

GeV

/c

-210

-110

1

10

210

310

)2 (GeV/cµInvariant Mass of e100 200 300 400 500 600 700

)2Ev

ents

/(10

GeV

/c

-210

-110

1

10

210

310)-1CDF Run II Preliminary (1 fb

) signal2(500 GeV/cτν∼=0.05132λ=0.10, 311’λ

DataPhysics Backgrounds

t , WW, t ττ → *γZ/Fake Backgrounds

+ jetsγ, W(+jets), dijets, µµ → *γZ/

Channelµe

)2 (GeV/cτµVisible Mass of 100 200 300 400 500 600 700

)2Ev

ents

/(10

GeV

/c

-210

-110

1

10

210

)2 (GeV/cτµVisible Mass of 100 200 300 400 500 600 700

)2Ev

ents

/(10

GeV

/c

-210

-110

1

10

210)-1CDF Run II Preliminary (1 fb

) signal2(500 GeV/cτν∼=0.05233λ=0.10, 311’λ



, dijetsµµ → *γW(+jets), Z/

Channelτµ

)2 (GeV/cτVisible Mass of e100 200 300 400 500 600 700

)2Ev

ents

/(10

GeV

/c

-210

-110

1

10

210

)2 (GeV/cτVisible Mass of e100 200 300 400 500 600 700

)2Ev

ents

/(10

GeV

/c

-210

-110

1

10

210

)-1CDF Run II Preliminary (1 fb) signal2(500 GeV/cτν∼=0.05133λ=0.10, 311’λ



ee→ *γ + jets, W(+jets), Z/γDijets,

Channelτe

Meµ Mµτ Meτ

-13-


Physics: RPV ντ

(GeV)τν∼M

100 150 200 250 300

311

’ λ95

% C

L

0

0.001

0.002

0.003

0.004

0.005

0.006=0.005312λ=0.01312λ=0.02312λ=0.07312λ


DØ:

• All RPV couplings are null butλ′311 and λ321 = λ312

• λ′311 ≤ 0.12, λ321 ≤ 0.07for Mντ < 100GeV

(GeV)τν∼M

100 150 200 250 300

)(fb)

µ B

R(e

× σ95

% C

L

0

5

10

1520

25

30

35

40

45

50

Observed LimitExpected Limit

σ1 ±Expected Limit σ2 ±Expected Limit


)2 Mass (GeV/cτν∼100 200 300 400 500 600 700 800

) (pb

)τµ

Br (

× σ95

% C

L

-210

-110

1

)2 Mass (GeV/cτν∼100 200 300 400 500 600 700 800

) (pb

)τµ

Br (

× σ95

% C

L

-210

-110

1

τµ → τν∼ → pN.L.O. p

=0.05233λ=0.10,311’λ

Observed

Expected

σ1

-1CDF Run II Preliminary, 1 fb

-14-


Physics: Chargino/Neutralino

DØ: arXiv 0901.0646

• ee, µµ, eµ, τµ + trk(e,µ,τ ) + 6ET

(GeV)eem0 50 100 150 200 250

Even

ts /

10 G

eV

-210

-110

1

10

210

(GeV)eem0 50 100 150 200 250

Even

ts /

10 G

eV

-210

-110

1

10

210Data

*, YγZ/Multijet

γW+jet/WW,ZZWZ

Data *, YγZ/

Multijet

γW+jet/WW,ZZWZ

tt

SUSY 1SUSY 2

-1DØ, 2.3 fbeel selection

CDF: PRL 101, 251801 (2008)

• 3 leptons (e, µ) + 6ET• 2 leptons (e, µ) + trk(e,µ,τ ) + 6ET

CDF 2fb−1, dilepton+trk:

7 vs 6.4±1.1 (all channels)fake ` 1.4, DY 3.0, dibosons 1.6, tt 0.5

-15-


Physics: Chargino/Neutralino

mSUGRA: 5 parametersm0, m1/2, tanβ, A0, sign(µ)

A0 = 0, tanβ = 3, µ > 0

Chargino Mass (GeV)100 110 120 130 140 150 160

BR(

3l) (

pb)

×) 20 χ∼ 1± χ∼ (σ

0

0.1

0.2

0.3

)20χ∼)>M(l~); M(

10χ∼2M(≈)

20χ∼M(≈)

1±χ∼M(

>0, no slepton mixingµ=3, βtan

-1DØ, 2.3 fb

LEP

3l-max

0large-m

Observed LimitExpected Limit

Chargino Mass (GeV)100 110 120 130 140 150 160

BR(

3l) (

pb)

×) 20 χ∼ 1± χ∼ (σ

0

0.1

0.2

0.3

3`-max:m( ˜, ν) > m(χ±1 , χ0

2),

no ˜ mixing

(GeV)0m0 50 100 150 200 250

(GeV

)1/

2m

150

200

250

300

(GeV)0m0 50 100 150 200 250

(GeV

)1/

2m

150

200

250

300 DØ observed limitDØ expected limitCDF observed

)-1limit (2.0 fb

LEP Chargino Limit

LEPSleptonLimit

-1DØ, 2.3 fbmSUGRA

> 0µ = 0, 0

= 3, Aβtan20χ∼

1±χ∼Search for

)2

0χ∼

M(

≈) l~M(

)1±χ∼

M(

≈) ν∼M

(

(GeV)0m0 50 100 150 200 250

(GeV

)1/

2m

150

200

250

300

βtan 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

BR(

3l) (

pb)

×) 20 χ∼ 1± χ∼ (σ

0

0.1

0.2

0.3

mSUGRA

) = 1 GeV20χ∼) - M(1τ∼)= 130 GeV; M(

1±χ∼M(

-1DØ, 2.3 fb

LEPObserved LimitExpected Limit

βtan 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

BR(

3l) (

pb)

×) 20 χ∼ 1± χ∼ (σ

0

0.1

0.2

0.3

-16-


Physics: Squark/Gluino

• squark q → qχ01, gluino g → qqχ0

1• 2 jets + 6ET: mq < mg ⇒ qq• 3 jets + 6ET: mq ∼ mg ⇒ qg• 4 jets + 6ET: mq > mg ⇒ gg• Reject leptons. Main backgrounds:

QCD, Z → νν+j, W → `ν+j, tt

CDF: PRL 102, 121801 (2009)

(3jets)[GeV] TH200 300 400 500 600 700 800 900

even

ts /

30 G

eV

-110

1

10

210

3 MET>120 HT>330≥ jetN CDF Run II Preliminary

)-1Data (L = 2.0 fbQCD + non QCD Bkg.non QCD Bkg.Total Syst. Uncertainty

2 = 249 GeV/cg~

Bkg.+Sig. M2 = 270 GeV/cs~ M

(3jets)[GeV] TH200 300 400 500 600 700 800 900

even

ts /

30 G

eV

-110

1

10

210

DØ: Phys. Lett. B 660 , 449 (2008)2j: low-m0, 3j: mq ≈ mg, 4j: high-m0

(GeV)TE0 50 100 150 200 250 300 350 400 450 500

Even

ts /

20 G

eV

-110

1

10

210

310

(GeV)TE0 50 100 150 200 250 300 350 400 450 500

Even

ts /

20 G

eV

-110

1

10

210

310 -1DØ, L=2.1 fb

DataSM BackgroundFitted QCDSUSY

(b)

-17-



CDF: PRL 102, 121801 (2009)

)2 (GeV/cg~M0 100 200 300 400 500 600

)2 (G

eV/c

q~M

0

100

200

300

400

500

600CDF Run II Preliminary -1L=2.0 fb

no mSUGRAsolution

LEP 1 + 2

UA1

UA2

FNAL Run I

g~

= Mq~M

)2 (GeV/cg~M0 100 200 300 400 500 600

)2 (G

eV/c

q~M

0

100

200

300

400

500

600observed limit 95% C.L.expected limit

<0µ=5, β=0, tan0A

Theoretical uncertainties includedin the calculation of the limit

mg ≈ mq: mg > 392 GeVany mq: mg > 280 GeVmq < 378 GeV : mg > 423 GeV

mq > 379 GeVmg > 308 GeV

Gluino Mass (GeV)0 100 200 300 400 500 600

Squa

rk M

ass

(GeV

)0

100

200

300

400

500

600

-1DØ, L=2.1 fb<0µ=0,

0=3, Aβtan

UA1

UA2

LEP

CDF

IB

DØ IA

DØ IB

DØ II

no mSUGRAsolution

±χ∼LEP2 ±l~LEP2

DØ: Phys. Lett. B 660 , 449 (2008)

-18-



-19-


Physics: CHAMPs

• Charged MAssive Stable Particles• Appear as “slow moving muons”• stop, stau, chargino, ...

CDF: arXiv 0902.1266, sub.to PRL

• Time of Flight (TOF) detector• Tracking•W → eν, Z → ee for TOF studies

DØ: arXiv 0809.0472, sub.to PRL

• Timing in µ system ⇒ the speed•M(µµ)• 1)Zµµ, 2)(1 − v)/σv < 0

Invariant Mass (GeV)0 200 400 600 800 1000

Even

ts

1

10

210

310

410∅(a) D Background

Stau (300 GeV)

Speed Significance Product0 50 100 150 200

Even

ts

10

210

310

410

510 ∅(b) D BackgroundStau (300 GeV)

-20-


Physics: CHAMPs

• Charged MAssive Stable Particles• Appear as “slow moving muons”• stop, stau, chargino, ...

CDF: arXiv 0902.1266, sub.to PRL

)2Stop Mass (GeV/c100 120 140 160 180 200 220 240 260

Cros

s se

ctio

n (p

b)

-210

-110

1

10 Stop Production cross section (NLO)µCross section limit from central

-1 = 1.03 fbL dt ∫

CDF Run II Preliminary

Same result implies:

• σch < 10fb at 95% CL for pchT >

40GeV , |ηch| < 1, 0.4 < βch < 0.9

DØ: arXiv 0809.0472, sub.to PRL

Mass [GeV]50 100 150 200 250 300

Cros

s se

ctio

n [p

b]

-310

-210

-110

1

10

Mass [GeV]50 100 150 200 250 300

Cros

s se

ctio

n [p

b]

-310

-210

-110

1

10Observed Cross Section LimitExpected Cross Section LimitNLO Cross Section PredictionNLO Cross Section Uncertainty

-1 1.1 fb∅D(b)

Limits for chargino mass for pair pro-duced gaugino-like charginos

-21-


Summary

• Supersymmetry is not discovered... yet

• Tevatron, CDF, DØ are running very well

• Data sample is getting bigger

– Expect 2-3 times more data to analyze

– Can look at the rarer signatures

– Keep digging and pushing limits

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

• DØ Exotics:http://www-d0.fnal.gov/Run2Physics/WWW/results/np.htm

-22-


Summary

• Keep your eyes open for the unexpected :)

-23-


Summary

• Stay tuned!

SUSY particle Scenario Mass Limit (GeV)

Squark and Gluino mSUGRA, low tanβ ≈ 400

Sbottom Br(g → bb) ≈ 100% ≈ 300

Stau RPV, λ′311 6=0, λ321 = λ312 6=0 ≈ 200

Chargino mSUGRA, 3` − max scenario ≈ 140

Stop Long life-time (CHAMP) ≈ 250

-24-


-BACKUP-SLIDES-

mSUGRA

-25-


mSUGRA

In mSUGRA, symmetry breaking is via gravitational interactions and theSUSY parameter space is reduced to only 5 parameters:

•m0: the universal scalar mass at the grand unification scale ΛGUT•m1/2: the universal gaugino mass at ΛGUT•A0: the universal trilinear coupling at ΛGUT• tanβ: the ratio of the vacuum expectation values of the two Higgs fields• µ: the sign of the Higgs-mixing mass parameter

2 4 6 8 10 12 14 16 18Log10(Q/1 GeV)

0

100

200

300

400

500

600

Mas

s [G

eV]

m0

m1/2

(µ2+m02)1/2

squarks

sleptons

M1

M2

M3

Hd

Hu

-26-

Documents

Andrey Loginov - Collider Detector at FermilabDIS 2009, Madrid, Spain, 26-30 April 2009 Andrey Loginov Search for SUSY at the Tevatron Why Standard Model (SM) †The SM describes data