r-parity violation at dØ. run i results and run ii prospects

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 1

R-parity violation at DØ.R-parity violation at DØ.Run I results and Run II Run I results and Run II

prospectsprospects

R-parity violation at DØ.R-parity violation at DØ.Run I results and Run II Run I results and Run II

prospectsprospects

On behalf of the DØ collaborationOn behalf of the DØ collaboration

Auguste BessonAuguste Besson(ISN-Grenoble, France)(ISN-Grenoble, France)

PHENO 2002 SYMPOSIUM

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 2

R-parity violation at DØR-parity violation at DØR-parity violation at DØR-parity violation at DØ• The TeVatron and the DØ detectorThe TeVatron and the DØ detector• R-parity violating SUSY (RPV)R-parity violating SUSY (RPV)• Pair production and RPV decays of Pair production and RPV decays of

LSPLSP and ’ couplings

• Resonant sparticle productionResonant sparticle production ’ and ’’ couplings

• Top decay via RPVTop decay via RPV ’ and ’’ couplings

• Conclusion and outlookConclusion and outlook

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 3

The TeVatronThe TeVatronThe TeVatronThe TeVatron• Run II started March 2001Run II started March 2001• Increased LuminosityIncreased Luminosity

– Main injector, RecyclerMain injector, Recycler– # bunches, # antiprotons# bunches, # antiprotons

• Increased EnergyIncreased Energy– 1.8 to 1.96 TeV1.8 to 1.96 TeV

CDF DØ

MI. + Recycler

TeVatron

2.32.32.52.5

13213239639635003500

~ 15~ 15~ 2~ 2~ 0.13~ 0.13

5.2x105.2x1032328.6x108.6x1031311.6x101.6x103030

1.961.961.961.961.81.8

140 x 103140 x 10336 x 3636 x 366 x 66 x 6

Run 2bRun 2bRun 2aRun 2aRun 1bRun 1b

4.84.8interactions/xinginteractions/xing

bunch xing (ns)bunch xing (ns)

Ldt (fbLdt (fb-1-1))

typ L (cmtyp L (cm-2-2ss-1-1))

s (TeV)s (TeV)

#bunches#bunches

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 4

Run IIa current LuminosityRun IIa current LuminosityRun IIa current LuminosityRun IIa current Luminosity

• typical Luminositytypical Luminosity ~ 10~ 103131 cm cm-2-2ss-1-1

• Integrated LIntegrated L ~ 36 pb~ 36 pb-1-1 delivered delivered

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 5

The DØ upgradeThe DØ upgradeThe DØ upgradeThe DØ upgrade• Run IRun I- excellent calorimetryexcellent calorimetry

LAr/U, hermetic, compensationLAr/U, hermetic, compensation

• Run II upgradeRun II upgrade- New trackingNew tracking

Silicon trackerSilicon tracker

Fiber trackerFiber tracker- Central solenoid Central solenoid

2 Teslas2 Teslas

- Preshower- Preshower

- Forward muon system- Forward muon system

- Electronics- Electronics

- Triggers- Triggers

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 6

• 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.

SupersymmetrySupersymmetrySupersymmetrySupersymmetry

llgggqqqpp jijiji

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

BosonFermionQFermionBosonQ ||;||

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 7

• 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 nb, L=nb Lepton B= Baryon nb, L=nb Lepton nb, S=spinnb, S=spin

RRpp= +1 = +1 SM particle SM particle

RRpp= -1 = -1 SUSY particle SUSY particle

not excluded theoriticallynot excluded theoritically

R-parityR-parityR-parityR-parityWWW RpVMSSMSUSY

kjikjikjiijkRpV DDUDQLELLW ijkijk

''' WithWith

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

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 8

R-parity violating : R-parity violating : consequencesconsequences

R-parity violating : R-parity violating : consequencesconsequences

• The Lightest Susy Particle (LSP) decays The Lightest Susy Particle (LSP) decays eithereither- inside the detector - inside the detector (with or without a displaced (with or without a displaced

vertex)vertex)

- outside the detector outside the detector (similar to Rp conserved (similar to Rp conserved analysis) analysis)

• 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

• LSP is not anymore a candidate for dark LSP is not anymore a candidate for dark mattermatter

kd

ju

il~

~

i'ijk

(+1)

(+1) (+1)

(-1)

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 9

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

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 10

RPV search at DØ : hypothesisRPV search at DØ : hypothesisRPV search at DØ : hypothesisRPV search at DØ : hypothesis

• mSUGRA framework mSUGRA framework (m(m00 ; m ; m1/21/2 ; A ; A00 ; sign ; sign ; tan ; tan ))

• LSPLSP• Only one Yukawa coupling Only one Yukawa coupling

((ijkijk,,’’ijkijk,,’’’’ijkijk) ) dominatesdominates

• Pair productionPair production

all pair production included, all pair production included,

then 2 LSP decay via RPV.then 2 LSP decay via RPV.• If RPV coupling is largeIf RPV coupling is large

resonant production is possibleresonant production is possible

01

~

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 11

• 2 susy particles produced 2 susy particles produced 2 LSP 2 LSP• Dominant coupling Dominant coupling ’’1jk 1jk (j=1,2 ; k=1,2,3)(j=1,2 ; k=1,2,3)• If LSP decays inside the detector:If LSP decays inside the detector:

coupling not to small,coupling not to small, ((’’1jk1jk >~ 10 >~ 10-3-3))LSP LSP 1 e + 2 jets 1 e + 2 jets

• Background: Background: Drell-Yan, tt,Drell-Yan, tt,

ZZee++ee- - + jets, misidentification of jets as electrons+ jets, misidentification of jets as electrons

• Cuts: Cuts: pTel pTel 15 & 10 GeV; pTjet 15 & 10 GeV; pTjet 15 GeV; Mee 15 GeV; Mee 76-106 GeV 76-106 GeV

Pair production: dielectron Pair production: dielectron channelchannelPair production: dielectron Pair production: dielectron channelchannel

Final State : 2 electrons + 4 jetsFinal State : 2 electrons + 4 jets

__

__

01

~e~

e

c

s

'122

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 12

Dielectron channel : mDielectron channel : m00-m-m1/21/2 plane planeDielectron channel : mDielectron channel : m00-m-m1/21/2 plane plane• Run I results :Run I results : L = 99 pbL = 99 pb-1 -1 , , s = 1.8 TeVs = 1.8 TeV

- Expected Backgd : - Expected Backgd :

1.8 1.8 0.2 0.2 0.3 0.3

- Events observed : - Events observed : 22

• Run II : Run II : L = 2fbL = 2fb-1-1, , s = 2 TeVs = 2 TeV

- Scenario I Scenario I Extrapolation from Run IExtrapolation from Run I

- Scenario IIScenario II upgraded detectorupgraded detector

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

Run II : Allanach et al. hep-ph/9906224

mg ~ 550 GeVmg ~ 550 GeVmq ~ 500 GeVmq ~ 500 GeV

~~~~

D0, Phys. Rev. Lett. 83, 4476 (99)

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 13

Pair production: dimuon channelPair production: dimuon channelPair production: dimuon channelPair production: dimuon channel

• Similar analysisSimilar analysis

• Dominant coupling Dominant coupling ’’2jk2jk

• Backgd : Backgd : Drell-Yan, tt, ZDrell-Yan, tt, Z+jets, Z+jets, Z,WW,WW + + jetsjets

• Cuts : Cuts : pTpT > 15 & 10 GeV, pT > 15 & 10 GeV, pTjetsjets > 15 GeV, > 15 GeV,

Scalar ET > 150 GeV, MScalar ET > 150 GeV, M>5GeV, Acoplanarity > 0.03>5GeV, Acoplanarity > 0.03

• Run I : Run I : L = 77.5 L = 77.5 4 pb 4 pb-1-1

Events observed = 0Events observed = 0

Expected Background = 0.18 Expected Background = 0.18 0.03 0.03 0.02 0.02

Final State : 2 muons + 4 jetsFinal State : 2 muons + 4 jets

01

~~

c

s

'222

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 14

dimuon channel : mdimuon channel : m00-m-m1/21/2 plane planedimuon channel : mdimuon channel : m00-m-m1/21/2 plane plane

AA00 = 0 ; = 0 ; < 0 ; tan < 0 ; tan = 2 = 2Run IRun I Run IIRun II (2fb-1)

D0, hep-ex/0111053 Submitted to PRL.

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 15

• 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 electronsmisidentification of jets as electrons

• Run I :Run I :

Pair production: multileptons channelPair production: multileptons channelPair production: multileptons channelPair production: multileptons channel

D0, PRL 80, 1592 (1998)D0, Phys. Rev. D Rapid. Comm. 62, 071701 (2000)

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

e01

~e

~

e121

eee ee e

L (pb-1) 97.85.2 97.85.2 93.14.9 78.34.1

Evts 0 0 0 0

Bkgd 0.340.07

0.610.36

0.110.04 0.200.04

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 16

multileptons channel : mmultileptons channel : m00-m-m1/21/2 planeplane

multileptons channel : mmultileptons channel : m00-m-m1/21/2 planeplane

• Contours :Contours :121121, , 122 122 oror

233233

< 0 or > 0 < 0 or > 0

tan tan = 5, 10 = 5, 10

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 17

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

EETT = = 13.9 GeV13.9 GeV

ppT T = = 10.9 GeV10.9 GeV

= = --1.941.94

= = 2.802.80

ChargeCharge = +1= +1

EETT = = 17.9 GeV17.9 GeV

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

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 18

MEMETT =31.8 GeV =31.8 GeV

mm = 41.5 GeV/c = 41.5 GeV/c22

2211ee

ppTT = = 9.9.82 GeV82 GeV

= = -1.48-1.48

= = 2.882.88

Charge = 1Charge = 1

ppTT = = 228.2 GeV8.2 GeV

= = -0.-0.1010

= = 6.206.20

Charge = -1Charge = -1

EETT = = 19.2 GeV19.2 GeV

= 0.40= 0.40

= 0.63= 0.63

No track matchNo track match

D Run 2 Preliminary

Muon

Electron

MET

Muon system

Muon

ee candidate event candidate eventee candidate event candidate event

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 19

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 jets

u d

d 1-~

+

~

d_

l -

l

W -

1o~

_

_

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 20

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

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 21

Resonant production : 3 leptons Resonant production : 3 leptons channelchannel

Resonant production : 3 leptons Resonant production : 3 leptons channelchannel

u d

d 1-~

+

~

d_

l -

l

W -

1o~

Déliot et al., EPJ C 19 (01) 155AA00 = 0 ; = 0 ; < 0 ; tan < 0 ; tan = 1.5 = 1.5

Final State : 3 Final State : 3 + 2 jets + 2 jets

Mass reconstructionMass reconstruction

Fast simulation: M̃01=77.7 GeV (MC input)

2 jets and softer muon: M̃01=71 GeV (9)

LLintint = 10fb = 10fb-1-1

’’211 211 = 0.09= 0.09

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 22

• Dominant coupling Dominant coupling ’’’’3jk3jk

Resonant stop productionResonant stop production

Stop decays to b Stop decays to b

to which decays outside the detectorto which decays outside the detector

• Backgd:Backgd:W+b-fake,Wbb,Wcc, single topW+b-fake,Wbb,Wcc, single top

• Cuts: Cuts: pTb > 40 GeV ;pTb > 40 GeV ;

pTlepton > 20 GeV;no other lepton or jetpTlepton > 20 GeV;no other lepton or jet

• Run I: 110 pbRun I: 110 pb-1-1

Resonant Squark Resonant Squark ProductionProduction

Resonant Squark Resonant Squark ProductionProduction

1

~

1~ 0

1~

d 1+~

b

t~

s''

3jk

l

l

W

1o~

Berger et al.,PRD 63, 115001 (01)

Final State : 1 charged lepton, 1 b-jet + missing ETFinal State : 1 charged lepton, 1 b-jet + missing ET

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 23

• Run II studies : Run II studies : ’’’’3jk3jk , 2 fb , 2 fb-1-1

– Perspectives with Fast simulation Perspectives with Fast simulation (SHW)(SHW)

Resonant Squark Resonant Squark ProductionProduction

Resonant Squark Resonant Squark ProductionProduction

Berger et al.,PRD 63, 115001 (01)

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 24

150 160 170 180 190 Sbottom Mass (GeV)

5.00

2.00

1.00

0.50

0.20

0.10

0.05

’’ 3

31

’’’’331 331 dominant couplingdominant coupling• tt production tt production t t bdbd

t t WW--b b llbb• decays outside the detectordecays outside the detector

• Backgd : Backgd : tt, Wbbjtt, Wbbj• Cuts : Cuts : pT> 20 GeV, |pT> 20 GeV, || < 2.5,| < 2.5, Rjj > 0.5Rjj > 0.5

• Run II studiesRun II studies

(fast simulation, 2fb(fast simulation, 2fb-1-1))

+ + ’’’’333 333 studiesstudies

Top decay via RPV : Run II Top decay via RPV : Run II studiesstudies

Top decay via RPV : Run II Top decay via RPV : Run II studiesstudies

Final state: 1 lepton + 2 b-jets + 1 jet + ETmissFinal state: 1 lepton + 2 b-jets + 1 jet + ETmiss

01

~__

__

01

~

''331t

bd

b~

01

~

Abraham et al. Phys.Lett.B 514 72 (2001) Abraham et al. Phys.Lett.B 514 72 (2001) Eilam et al. Eilam et al. Phys.Lett.BPhys.Lett.B 510510 227227 ( (20012001))

__ __

Han et al. Phys. Lett.B 476 79 (2000)Han et al. Phys. Lett.B 476 79 (2000)

__

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 25

ConclusionConclusionConclusionConclusion• RUN I : RUN I : many channels and couplings many channels and couplings

exploredexplored

• RUN IIa : RUN IIa : – improved detector ; Limproved detector ; Lintint10 ; 10% more 10 ; 10% more

energyenergy– DØ is already taking data.DØ is already taking data.

~ 300 pb~ 300 pb-1-1 expected at the end of 2002. expected at the end of 2002.

~ 2 fb~ 2 fb-1-1 in 2004. in 2004.– Great discovery potential both in pair/single Great discovery potential both in pair/single

production.production.

No RPV signal foundNo RPV signal found

Pheno 2002 Symposium, Madison, April 22-24 2002 Auguste Besson 26

Feynman diagramsFeynman diagramsFeynman diagramsFeynman diagrams

• Via Via ’’122122

01

~e~

e

cs

'122

122'

ev~

s

sc~

e

ss~

e

s

e~c

ss~

e

ss~

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c