Supersymmetry at D Ø

Supersymmetry at DSupersymmetry at DØØSupersymmetry at DSupersymmetry at DØØ

and other new phenomena searches in and other new phenomena searches in Run IIRun II

– TeVatron and DTeVatron and DØØ upgrade upgrade– Run II preliminary studiesRun II preliminary studies

• mSUGRA : squarks and gluinos jet + mETmSUGRA : squarks and gluinos jet + mET• GMSB : diphotonsGMSB : diphotons• RPV : trileptons / likesign dileptonsRPV : trileptons / likesign dileptons• Extra-dimensionsExtra-dimensions

Auguste BESSON for the D0 collaborationAuguste BESSON for the D0 collaboration

PASCOS 2003PASCOS 2003

PASCOS 2003. 3-8 January 2003 Auguste Besson for D0 collab. 2

TeVatron TeVatron upgradeupgradeTeVatron TeVatron upgradeupgrade

Main Injector & Recycler

Tevatron

p source

Booster

p

p CDFDØ

• p-pbar colliderp-pbar collider• Run IIa : Run IIa : march 2001march 2001• Energy: Energy: 1.8 1.8 1.96 TeV 1.96 TeV

• LuminosityLuminosity– new injector : new injector : main injectormain injector– # bunches : # bunches : 6 x 6 6 x 6 → → 336 x 366 x 36– pbar production pbar production – pbar recycling : pbar recycling :

Recycler Recycler (Run IIb)(Run IIb)

FermilaFermilabb


TeVatron upgrade TeVatron upgrade (2)(2)TeVatron upgrade TeVatron upgrade (2)(2)Run 1bRun 1b Run 2aRun 2a Run 2 Run 2

upgradeupgradetimetime 1990-961990-96 2001-20052001-2005 start 2005-06start 2005-06

p/bunch p/bunch (10(101111)) 2.32.3 2.72.7 2.72.7

pbar/bunch pbar/bunch (10(101010)) 5.55.5 3.03.0 1010

# bunches# bunches 6 x 66 x 6 36 x 3636 x 36 140 x 103140 x 103

bunch length bunch length (cm)(cm) 6060 3737 3737

time between bunch time between bunch (ns)(ns) ~ 3500~ 3500 396396 132132

# interactions/crossing# interactions/crossing 2.52.5 2.32.3 4.84.8

crossing angle crossing angle ((rad)rad) 00 00 136136

p/p emittance p/p emittance (mm mrad)(mm mrad) 2323/13/13 2020/15/15 2020/15/15

s s (TeV)(TeV) 1.81.8 1.961.96 1.961.96

Instantaneous LInstantaneous L (10(103131cmcm-2-2ss--

11))0.160.16 8.68.6 5252

∫∫Ldt Ldt (pb(pb-1-1/week)/week) 3.23.2 17.317.3 105105integrated ∫Ldt integrated ∫Ldt (fb (fb-1-1)) ~ 0.13~ 0.13 ~ 2~ 2 10-1510-15


Run IIa : Run IIa : current luminositycurrent luminosityRun IIa : Run IIa : current luminositycurrent luminosity

∫ ∫L.dt L.dt on tapeon tape ~ 50 pb~ 50 pb-1-1 (october 2002)(october 2002)

~ 75 pb~ 75 pb-1-1 (mid-december (mid-december 2002)2002)

date

• Maximum LuminosityMaximum Luminosity = 3.6 = 3.6 x 10x 103131 cm cm-2-2ss-1-1

• Delivered luminosityDelivered luminosity ~ 150 ~ 150 pbpb-1-1

(9 december 2002)(9 december 2002)

week


The DØ collaboration The DØ collaboration The DØ collaboration The DØ collaboration

~ 650 physicists; 76 institutions; 18 ~ 650 physicists; 76 institutions; 18 countriescountries~ 650 physicists; 76 institutions; 18 ~ 650 physicists; 76 institutions; 18 countriescountries


DDØØ upgrade upgradeDDØØ upgrade upgrade• Run IRun I- CalorimeterCalorimeter

LAr/U, compensateLAr/U, compensate

• Run II Run II upgradeupgrade

- trackingtrackingSilicon vertexSilicon vertexFiber trackerFiber tracker

- solsoleenoid noid 2 T magnetic field2 T magnetic field

- PreshowerPreshower- Muons detectorMuons detector- EElectronicslectronics- Trigger system- Trigger system


MSSM / mSUGRAMSSM / mSUGRAMSSM / mSUGRAMSSM / mSUGRA

productionproduction

Cross-sectionsCross-sectionsRun II preliminary study: Run II preliminary study:

squarks/gluinossquarks/gluinos


Susy productionSusy productionSusy productionSusy production

• Neutralinos/charginosNeutralinos/charginos– trilepton channeltrilepton channel– dilepton channeldilepton channel

• sleptons sleptons cross-section small.cross-section small.

• squarks/gluinossquarks/gluinos– jet + mETjet + mET– single single + jets + mET + jets + mET

• stops and sbottomstops and sbottom

llgggqqqpp jijiji

~~,~~,~~,~~,~~,~~,~~ 000

b1 b 20

10 e+ e-~

~ ~


cross-section cross-section (mSUGRA)(mSUGRA)

cross-section cross-section (mSUGRA)(mSUGRA)

For For mm1/21/2> 100 > 100 GeVGeV

andand m m00> 100 > 100 GeVGeV

pair production of pair production of

Charginos/NeutralinCharginos/Neutralinos os

dominatesdominates

For For mm1/21/2> 100 > 100 GeVGeV

andand m m00> 100 > 100 GeVGeV

pair production of pair production of

Charginos/NeutralinCharginos/Neutralinos os

dominatesdominates

mm1/21/2 is the crucial is the crucial parameterparameter

mm00= 100= 100tan tan = 5 = 5 < 0< 0

mm1/2 1/2 (GeV)(GeV)

Cro

ss-s

ecti

on

(p

b)

Cro

ss-s

ecti

on

(p

b)

±±00

squarkssquarks

0000

±±±±

sleptonssleptons

AA00 = 0; m = 0; m00 = 100; tan = 100; tan = 5; = 5; < 0 < 0


Cross-section (squarks)Cross-section (squarks)Cross-section (squarks)Cross-section (squarks)• squark productions depend squark productions depend

‘’‘’only’’ on their massonly’’ on their masstan tan = 5; = 5; < 0; A < 0; A00 = 0 = 0

Cross-sectionCross-sectionSquark-squark +Squark-squark +Squark-antisquarkSquark-antisquark

Squarks dominateSquarks dominate

Cro

ss-s

ecti

on

(p

b)

Cro

ss-s

ecti

on

(p

b)

squark masssquark mass (GeV)(GeV) mm0 0 (GeV)(GeV)

mm1

/2

1/2

(G

eV

)(G

eV

)


squarks and gluinossquarks and gluinossquarks and gluinossquarks and gluinos

• Final StateFinal State>=2 jets + mET>=2 jets + mET

PRL 83, 4937 (1999)

no E

WSB

Run IRun IRun IRun I

tan tan = 2; = 2; < 0; A < 0; A00 = 0 = 0

D0 Run II preliminaryD0 Run II preliminaryD0 Run II preliminaryD0 Run II preliminary

2 jets2 jetsmETmET

D0 Run II preliminaryD0 Run II preliminary

(jet1-jet2)(jet1-jet2)

- MC. Data

L ~ 6 pbL ~ 6 pb-1-1

significant cuts:mET, pTjets scalar sum of ETacoplanarity

GMSBGMSBGMSBGMSB

frameworkframeworkRun II preliminary study: Run II preliminary study: di-photons + di-photons +

mETmET


GMSBGMSBGMSBGMSB• Minimal Model of Gauge Mediation (MGM) Minimal Model of Gauge Mediation (MGM)

6 parameters :6 parameters : effective visible sector SUSY breaking parametereffective visible sector SUSY breaking parameterNN number of messengernumber of messengerMMmm mass scale of messengersmass scale of messengerstan tan ratio of v.e.v. of the 2 higgs doubletsratio of v.e.v. of the 2 higgs doubletssign(sign()) sign of mixing parameter of higgsinossign of mixing parameter of higgsinosCCGG ratio of the messenger sector SUSY breaking ratio of the messenger sector SUSY breaking order parameter to the intrinsic SUSY breaking order parameter to the intrinsic SUSY breaking parameterparameter

– NLSP nature. either: NLSP nature. either:

0011, stau, slepton, squark, etc., stau, slepton, squark, etc.– lifetime of NLSPlifetime of NLSP– signature:signature:

+mET; l+mET; lll+mET ; +mET ; +mET,+mET,

monojetmonojet

Fermilab Run II workshop:Baer et al. hep-ph/0008070Baer et al. hep-ph/9903333


• Neutralino NLSPNeutralino NLSP

• Final state:Final state: + mET + X+ mET + X

N = 1; MN = 1; Mmm = 2 = 2 ;; tan tan =15; =15; > 0 > 0

• BackgroundBackgroundWW,Wj,Zee,tt,WW,WZ,etc.,Wj,Zee,tt,WW,WZ,etc.

• Cuts: Cuts: pTpT > 20 GeV, track veto > 20 GeV, track veto(Jet,mET)>0.5(Jet,mET)>0.5MM 80-102 GeV, vertex 80-102 GeV, vertex

mET > 25 GeVmET > 25 GeV

di-photons + mETdi-photons + mETdi-photons + mETdi-photons + mET


D0. PRL 80, 3, 442 (1998)

Run II preliminary:Run II preliminary:Run II preliminary:Run II preliminary:

D0 Run II D0 Run II preliminarypreliminaryD0 Run II D0 Run II preliminarypreliminary

Expected BkdExpected Bkd 1.0 1.0 0.3 0.3

DataData 22

8.78.71.2 pb1.2 pb-1-1

- MC.+ Data

R-Parity violated (RPV)R-Parity violated (RPV)R-Parity violated (RPV)R-Parity violated (RPV)

consequencesconsequences

LSP decayLSP decay

Run II preliminary study: Run II preliminary study: like sign dileptonslike sign dileptons

trileptonstrileptons


• SUSY potential: SUSY potential:

i,j,k = 1,2,3i,j,k = 1,2,3 (family indices)(family indices) 9 + 27 + 99 + 27 + 9 = 45 new Yukawa couplings. = 45 new Yukawa couplings. Lepton (Lepton ( and and ’) or Baryon (’) or Baryon (’’) ’’)

number number not conservednot conserved define R-parity : define R-parity : discrete quantum numberdiscrete quantum number

B= Baryon #, L=Lepton #, B= Baryon #, L=Lepton #, S=spinS=spin

RRpp= +1 = +1 SM particle SM particle

RRpp= -1 = -1 SUSY particle SUSY particle

WWW RpVMSSMSUSY WWW RpVMSSMSUSY

kjikjikjiijkRpV DDUDQLELLW ijkijk

''' kjikjikjiijkRpV DDUDQLELLW ijkijk

''' WithWith

Rp = (-1)3B+2S+LRp = (-1)3B+2S+L

R-parityR-parityR-parityR-parity


• R-p conserved:R-p conserved:- LSP stable and candidate for dark matter LSP stable and candidate for dark matter - Susy particles pair producedSusy particles pair produced

• R-p violated:R-p violated: B or L not conserved B or L not conserved

• Lightest Susy Particle (LSP) decays eitherLightest Susy Particle (LSP) decays either- inside the detector - inside the detector (with or without a displaced vertex)(with or without a displaced vertex)

- outside the detectoroutside the detector • Susy signature can be very differentSusy signature can be very different

– Less missing EtLess missing Et– More leptons More leptons (( or or ’)’) and jets and jets ((’ or ’ or ’’)’’)

• Single Susy particle production is possibleSingle Susy particle production is possible- via via ’ or ’ or ’’ @ TeVatron’’ @ TeVatron- cross-section cross-section ( (’’ijkijk))22

llgggqqqpp jijiji

~~,~~,~~,~~,~~,~~,~~ 000 llgggqqqpp jijiji

~~,~~,~~,~~,~~,~~,~~ 000

q g

q_

q~

q~

_(+1)

(+1)

(-1)

(-1)

(+1)

kd

ju

il~

~

i'ijk

(+1)

(+1)

(-1)

01

~e~

e

c

s'122

R-parity: consequencesR-parity: consequencesR-parity: consequencesR-parity: consequences


RPV example: RPV example: ’’122122 couplingscouplings

RPV example: RPV example: ’’122122 couplingscouplings

’’122 122 LL11QQ22DD22

• Via Via ’’122122

01

~e~

e

cs

'122

122'

ev~

s

sc~

e

ss~

e

s

e~c

ss~

e

ss~

e

c

(+ cplx. conjugate)(+ cplx. conjugate)

__

01

~~

s

s

'122OROR


’’122 122 :: like sign like sign dileptonsdileptons

’’122 122 :: like sign like sign dileptonsdileptons

• Final stateFinal state2 likesign e2 likesign e + 4 jets + 4 jets

• Backgd: Backgd: Drell-Yan, Zee, tt, Drell-Yan, Zee, tt,

e+efake, wrong sign assignmente+efake, wrong sign assignment• pT el > 15 GeVpT el > 15 GeV

AA00 = 0 ; = 0 ; < 0 ; tan < 0 ; tan = 2 = 2D0, Phys. Rev. Lett. 83, 4476 (99)


Run IIa simulationRun IIa simulationRun IIa simulationRun IIa simulation


2 like sign leptons + >= 1 2 like sign leptons + >= 1 jetsjets

SM backgdSM backgd 0.1 0.1 0.10.1

InstrumentalInstrumental 2.8 2.8 1.3 1.3

DataData 22


jet multiplicity for dielectrons events

jet multiplicity for dielectrons events

mm0 0 (GeV)(GeV)

mm1

/2

1/2

(G

eV

)(G

eV

)

L = 9.7 L = 9.7 1.4 pb 1.4 pb-1-1

- MC.+ Data


coupling: trilepton coupling: trilepton channelchannel

coupling: trilepton coupling: trilepton channelchannel

• Dominant coupling Dominant coupling 121121, , 122 122 oror 233233

LSP LSP 2 charged leptons + 1 2 charged leptons + 1

• Backgd: Backgd: Drell-Yan, tt, ZDrell-Yan, tt, Z,,

misidentification of jets as electrons, cosmic misidentification of jets as electrons, cosmic

Final State : Final State : eee,ee eee,ee,e,e,, + missing ET + missing ETFinal State : Final State : eee,ee eee,ee,e,e,, + missing ET + missing ET

e01

~e

~

e121

e e ee e e

SM backgdSM backgd 0.9 0.9 0.20.2

InstrumentalInstrumental 1 1 0.3 0.3

DataData 22

e e e e

SM backgdSM backgd 0.13 0.13 0.08 0.08

e + e + + e fake + e fake 0.6 0.6 0.2 0.2

e + e + cosmic e + e + cosmic

0.145 0.145 0.0140.014

DataData 11


L = 5.2 L = 5.2 0.8 pb0.8 pb-1-1

Large Extra DimensionsLarge Extra DimensionsLarge Extra DimensionsLarge Extra Dimensions


Large extra dimensionsLarge extra dimensionsLarge extra dimensionsLarge extra dimensions• Virtual gravitonVirtual graviton

– Planck scale MsPlanck scale Ms

• final statefinal state ee, ee, , ,

Instrumental- Inst. + S.M. backgd

+ Data

Run I Limit: (95% C.L.)Run I Limit: (95% C.L.)Ms(GRW) > 1.2 TeVMs(GRW) > 1.2 TeVRun II preliminary:Run II preliminary:Ms(GRW) > 0.92 TeVMs(GRW) > 0.92 TeV

L = 9.9 pbL = 9.9 pb-1-1L = 9.9 pbL = 9.9 pb-1-1

diEM Mass (GeV)diEM Mass (GeV)

cos

cos

**

S.M.S.M.S.M.S.M. DataDataDataData

E.D. E.D. signalsignalE.D. E.D. signalsignal

QCDQCDQCDQCD


di-photon candidatedi-photon candidatedi-photon candidatedi-photon candidate


ETET11(GeV)(GeV) ETET22 11 22 cos cos ** MM mETmET

120.3120.3 106.106.22

0.100.10 -2.10-2.10 0.770.77 377377 12.612.6


ConclusionConclusionConclusionConclusion• D0 detector: D0 detector: upgrade is a successupgrade is a success

tremendous effort on calibration, tremendous effort on calibration, comissioning,comissioning,

instrumental backgd, particle ID, etc.instrumental backgd, particle ID, etc.

• first new phenomena analysis underwayfirst new phenomena analysis underway– many exciting channelsmany exciting channels

• Luminosity Luminosity large progress during the last monthslarge progress during the last months

– now: ~ 50 pbnow: ~ 50 pb-1-1 on tape on tape– ~ 200 pb~ 200 pb-1-1 in summer 2003 in summer 2003– First Run II limits in the coming months.First Run II limits in the coming months.

(better than the Run I results)(better than the Run I results)Stay tuned !Stay tuned !

Back upBack upBack upBack up


• SUSY SUSY - New symmetry between fermions and - New symmetry between fermions and bosonsbosons- Solves hierarchy problem- Solves hierarchy problem- allows convergence of coupling - allows convergence of coupling constants at GUT scaleconstants at GUT scale- complete new spectrum of susy - complete new spectrum of susy particlesparticles..

• In most of the modelsIn most of the models- SUSY particles are pair produced- SUSY particles are pair produced

- The lightest SUSY particle (LSP) is - The lightest SUSY particle (LSP) is stable and escape from detector.stable and escape from detector.

SUSY frameworkSUSY frameworkSUSY frameworkSUSY framework

llgggqqqpp jijiji

~~,~~,~~,~~,~~,~~,~~ 000

BosonFermionQFermionBosonQ ||;||


2,3 and 4 2,3 and 4 bodybody

decays of decays of stopstop

2,3 and 4 2,3 and 4 bodybody

decays of decays of stopstop


RPV Experimental RPV Experimental constraintsconstraints

RPV Experimental RPV Experimental constraintsconstraints

• Indirect limits via low energy processesIndirect limits via low energy processes- e-e--- universality - Neutrinoless double-beta decay universality - Neutrinoless double-beta decay

- Charged current universality - Top decay- Charged current universality - Top decay

- Atomic parity violation - etc.- Atomic parity violation - etc.

• 22 limits for m = 100 GeV limits for m = 100 GeV (limits often linear in mass)(limits often linear in mass)

• Stronger limitsStronger limits

on products on products

of couplingof coupling

-- proton decay :proton decay :

’’’’11k 11k . . ’’11k11k < 10 < 10-22-22

Barger et al. Phys.Rev. D40 (89)Ledroit, Sajot GDR-S-008 (98)Allanach et al., PRD 60 (99)

~~

u

ud

u

ddkk

~~

d_e+

pp


Resonant production : dimuons Resonant production : dimuons channelchannel

Resonant production : dimuons Resonant production : dimuons channelchannel

• Dominant coupling Dominant coupling ’’211211

resonant prod via RPV resonant prod via RPV Decay of LSP via RPVDecay of LSP via RPV

• Backgd : Backgd : tt, Z+2jets, WW+jetstt, Z+2jets, WW+jets

• Cuts : Cuts : pTpT 20 GeV ; pT 20 GeV ; pTjets jets 20 GeV 20 GeV

Scalar ET Scalar ET 50 GeV ; 50 GeV ; RRjets jets 0.5 0.5

u 1o~

L

~

d_

u d

'211

Final State : Final State : 2 2 + 2 jets + 2 jetsFinal State : Final State : 2 2 + 2 jets + 2 jets

u d

d 1-~

+

~

d_

l -

l

W -

1o~

_

_


Dimuons in mDimuons in m00-m-m1/21/2 planeplane

Dimuons in mDimuons in m00-m-m1/21/2 planeplane

• Run I: Run I: L = 94 L = 94 5 pb 5 pb-1-1

Events observed = 5Events observed = 5

Expected Background = 5.34 Expected Background = 5.34 0.07 0.07

AA00 = 0 ; = 0 ; < 0 ; tan < 0 ; tan = 1.5 = 1.5

95% conf. level95% conf. level

• Run II: Run II: (Fast (Fast simulation)simulation) ’’211211=0.05=0.05

preliminarypreliminary

Déliot et al., EPJ C 19 (01) 155

AA00 = 0 ; = 0 ; < 0 ; tan < 0 ; tan = 2 = 2


mme1e2e3e1e2e3 = 85.2 = 85.2 GeV/cGeV/c22 MEMETT =10.7 GeV =10.7 GeV

mme2e3e2e3 = 63.5 = 63.5mme1e3e1e3 = 10.8 = 10.8mme1e2e1e2 = 55.7 = 55.7

e3e3e2e2e1e1

EETT = = 13.2 GeV13.2 GeV

ppTT = 15.1 GeV = 15.1 GeV

= = 1.1.0606

= = 5.725.72

ChargeCharge = -1= -1


ppT T = = 10.9 GeV10.9 GeV

= = --1.941.94

= = 2.802.80

ChargeCharge = +1= +1


ppTT = = 0.52 GeV0.52 GeV

= 0.43= 0.43

= 5.42= 5.42

ChargeCharge = +1= +1

D Run 2 Preliminary

Electrons

Trilepton eventsare classical

SUSY signatureElectron

eee candidate eventeee candidate eventeee candidate eventeee candidate event


MEMETT =31.8 GeV =31.8 GeV

mm = 41.5 GeV/c = 41.5 GeV/c22

2211ee

ppTT = = 9.9.82 82 GeVGeV

= = -1.48-1.48

= = 2.882.88

Charge = 1Charge = 1

ppTT = = 228.2 8.2 GeVGeV

= = -0.-0.1010

= = 6.206.20

Charge = -1Charge = -1


= 0.40= 0.40

= 0.63= 0.63

No track No track matchmatch

Muon

Electron

MET

Muon system

Muon

ee candidate event candidate eventee candidate event candidate eventD Run 2 PreliminaryD0 Run II preliminaryD0 Run II preliminaryD0 Run II preliminaryD0 Run II preliminary


eeee candidate event candidate eventeeee candidate event candidate eventD0 Run II preliminaryD0 Run II preliminaryD0 Run II preliminaryD0 Run II preliminary

Documents

Supersymmetry at D Ø