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PASCOS 2003. Supersymmetry at D Ø. and other new phenomena searches in Run II TeVatron and D Ø upgrade Run II preliminary studies mSUGRA : squarks and gluinos jet + mET GMSB : diphotons RPV : trileptons / likesign dileptons Extra-dimensions. Auguste BESSON for the D0 collaboration.

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supersymmetry at d

PASCOS 2003

Supersymmetry at DØ

and other new phenomena searches in Run II

TeVatron and DØ upgrade

Run II preliminary studies

mSUGRA : squarks and gluinos jet + mET

GMSB : diphotons

RPV : trileptons / likesign dileptons

Extra-dimensions

Auguste BESSON for the D0 collaboration

tevatron upgrade
TeVatron upgrade

p

CDF

Booster

Fermilab

Tevatron

  • p-pbar collider
  • Run IIa : march 2001
  • Energy: 1.8  1.96 TeV
  • Luminosity
    • new injector : main injector
    • # bunches : 6 x 6 → 36 x 36
    • pbar production 
    • pbar recycling :

Recycler (Run IIb)

p

p source

Main Injector

& Recycler

Auguste Besson for D0 collab.

tevatron upgrade 2
TeVatron upgrade (2)

Auguste Besson for D0 collab.

run iia current luminosity
Run IIa : current luminosity
  • Maximum Luminosity
  • = 3.6 x 1031 cm-2s-1
  • Delivered luminosity
  • ~ 150 pb-1
  • (9 december 2002)

week

∫L.dt on tape

~ 50 pb-1(october 2002)

~ 75 pb-1(mid-december 2002)

date

Auguste Besson for D0 collab.

the d collaboration
The DØ collaboration

~ 650 physicists; 76 institutions; 18 countries

Auguste Besson for D0 collab.

d upgrade
DØ upgrade
  • Run I
  • Calorimeter

LAr/U, compensate

  • Run II upgrade
  • tracking

Silicon vertex

Fiber tracker

  • solenoid

2 T magnetic field

  • Preshower
  • Muons detector
  • Electronics

- Trigger system

Auguste Besson for D0 collab.

mssm msugra

MSSM / mSUGRA

production

Cross-sections

Run II preliminary study: squarks/gluinos

susy production

~

~

b1 b 20

 10 e+ e-

~

Susy production
  • Neutralinos/charginos
    • trilepton channel
    • dilepton channel
  • sleptons cross-section small.
  • squarks/gluinos
    • jet + mET
    • single  + jets + mET
  • stops and sbottom

Auguste Besson for D0 collab.

cross section msugra
cross-section (mSUGRA)

A0 = 0; m0 = 100; tan  = 5;  < 0

m1/2 is the crucial parameter

m0= 100

tan  = 5

 < 0

±0

Cross-section (pb)

±±

sleptons

For m1/2> 100 GeV

and m0> 100 GeV

pair production of

Charginos/Neutralinos

dominates

squarks

00

m1/2 (GeV)

Auguste Besson for D0 collab.

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

‘’only’’ on their mass

tan  = 5;  < 0; A0 = 0

Cross-section

Squark-squark +

Squark-antisquark

m1/2 (GeV)

Cross-section (pb)

squark mass(GeV)

m0 (GeV)

Squarks dominate

Auguste Besson for D0 collab.

squarks and gluinos
squarks and gluinos

PRL 83, 4937 (1999)

tan  = 2;  < 0; A0 = 0

  • Final State

>=2 jets + mET

Run I

L ~ 6 pb-1

significant cuts:

mET, pTjets

scalar sum of ET

acoplanarity

no EWSB

D0 Run II preliminary

- MC.

 Data

D0 Run II preliminary

mET

2 jets

(jet1-jet2)

Auguste Besson for D0 collab.

slide13

GMSB

framework

Run II preliminary study: di-photons + mET

slide14
GMSB

Fermilab Run II workshop:

Baer et al. hep-ph/0008070

Baer et al. hep-ph/9903333

  • Minimal Model of Gauge Mediation (MGM) 6 parameters :

effective visible sector SUSY breaking parameter

Nnumber of messenger

Mmmass scale of messengers

tan ratio of v.e.v. of the 2 higgs doublets

sign()sign of mixing parameter of higgsinos

CGratio of the messenger sector SUSY breaking

order parameter to the intrinsic SUSY breaking

parameter

    • NLSP nature. either:

01, stau, slepton, squark, etc.

    • lifetime of NLSP
    • signature:

+mET; ll+mET ; +mET,

monojet

Auguste Besson for D0 collab.

di photons met
di-photons + mET

D0. PRL 80, 3, 442 (1998)

  • Neutralino NLSP
  • Final state:

 + mET + X

N = 1; Mm = 2  ;tan  =15;  > 0

  • Background

W,Wj,Zee,tt,WW,WZ,etc.

  • Cuts: pT > 20 GeV, track veto

(Jet,mET)>0.5

M  80-102 GeV, vertex

mET > 25 GeV

Run I

Run II preliminary:

D0 Run II preliminary

8.71.2 pb-1

- MC.

+ Data

Auguste Besson for D0 collab.

r parity violated rpv

R-Parity violated (RPV)

consequences

LSP decay

Run II preliminary study:

like sign dileptons

trileptons

r parity
R-parity
  • SUSY potential:
  • i,j,k = 1,2,3(family indices)

 9 + 27 + 9 = 45 new Yukawa couplings.

  • Lepton ( and ’) or Baryon (’’) number not conserved
  •  define R-parity : discrete quantum number
    • B= Baryon #, L=Lepton #, S=spin
    • Rp= +1  SM particle
    • Rp= -1  SUSY particle

With

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

Auguste Besson for D0 collab.

r parity consequences

(-1)

(+1)

(+1)

(-1)

(-1)

(+1)

(+1)

(+1)

_

q

g

q

_

~

~

q

q

R-parity: consequences
  • R-p conserved:
    • LSP stable and candidate for dark matter
    • Susy particles pair produced
  • R-p violated: B or L not conserved
  • Lightest Susy Particle (LSP) decays either
    • - inside the detector (with or without a displaced vertex)
    • outside the detector
  • Susy signature can be very different
    • Less missing Et
    • More leptons ( or ’)and jets (’ or ’’)
  • Single Susy particle production is possible
    • via ’ or ’’ @ TeVatron
    • cross-section  (’ijk)2

Auguste Besson for D0 collab.

rpv example 122 couplings
RPV example: ’122couplings
  • ’122 L1Q2D2
  • Via ’122

_

(+ cplx. conjugate)

OR

Auguste Besson for D0 collab.

122 like sign dileptons

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

Run IIa simulation

Run I

’122 :like sign dileptons

A0 = 0 ;  < 0 ; tan  = 2

  • Final state

2 likesign e + 4 jets

  • Backgd: Drell-Yan, Zee, tt,

e+efake, wrong sign assignment

  • pT el > 15 GeV

m1/2 (GeV)

m0 (GeV)

D0 Run II preliminary

jet multiplicity

for dielectrons events

L = 9.7  1.4 pb-1

D0 Run II preliminary

- MC.

+ Data

Auguste Besson for D0 collab.

coupling trilepton channel
 coupling: trilepton channel
  • Dominant coupling 121, 122 or233

LSP  2 charged leptons + 1 

  • Backgd: Drell-Yan, tt, Z,

misidentification of jets as electrons, cosmic 

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

D0 Run II preliminary

L = 5.2 0.8 pb-1

Auguste Besson for D0 collab.

large extra dimensions1

 Instrumental

- Inst. + S.M. backgd

+ Data

Large extra dimensions
  • Virtual graviton
    • Planck scale Ms
  • final state

ee, , 

S.M.

L = 9.9 pb-1

Data

QCD

E.D. signal

Run I Limit: (95% C.L.)

Ms(GRW) > 1.2 TeV

Run II preliminary:

Ms(GRW) > 0.92 TeV

cos *

diEM Mass (GeV)

Auguste Besson for D0 collab.

di photon candidate
di-photon candidate

D0 Run II preliminary

Auguste Besson for D0 collab.

conclusion
Conclusion
  • D0 detector: upgrade is a success

tremendous effort on calibration, comissioning,

instrumental backgd, particle ID, etc.

  • first new phenomena analysis underway
    • many exciting channels
  • Luminosity large progress during the last months
    • now: ~ 50 pb-1 on tape
    • ~ 200 pb-1 in summer 2003
    • First Run II limits in the coming months.

(better than the Run I results)

Stay tuned !

Auguste Besson for D0 collab.

susy framework
SUSY framework
  • SUSY
  • - New symmetry between fermions and bosons
  • - Solves hierarchy problem
  • - allows convergence of coupling constants at GUT scale
  • - complete new spectrum of susy particles.
  • In most of the models
  • - SUSY particles are pair produced
  • - The lightest SUSY particle (LSP) is stable and escape from detector.

Auguste Besson for D0 collab.

2 3 and 4 body decays of stop
2,3 and 4 body decays of stop

Auguste Besson for D0 collab.

rpv experimental constraints
RPV Experimental constraints
  • Indirect limits via low energy processes
  • e-- universality - Neutrinoless double-beta decay

- Charged current universality - Top decay

- Atomic parity violation - etc.

  • 2 limits for m = 100 GeV

(limits often linear in mass)

  • Stronger limits

on products

of coupling

-proton decay :

’’11k . ’11k < 10-22

~

Barger et al. Phys.Rev. D40 (89)

Ledroit, Sajot GDR-S-008 (98)

Allanach et al., PRD 60 (99)

~

dk

e+

_

u

p

d

d

u

u

Auguste Besson for D0 collab.

resonant production dimuons channel

~

~

~



1-

1o

_

d

Resonant production : dimuons channel

_

~

  • Dominant coupling ’211

 resonant prod via RPV

  • Decay of LSP via RPV
  • Backgd : tt, Z+2jets, WW+jets
  • Cuts : pT  20 GeV ; pTjets  20 GeV

Scalar ET  50 GeV ; Rjets  0.5

1o

~

u

u d

L

_

_

d

u d

l -

d

W -

Final State :  2  + 2 jets

l

+

Auguste Besson for D0 collab.

dimuons in m 0 m 1 2 plane
Dimuons in m0-m1/2 plane

A0 = 0 ;  < 0 ; tan  = 2

preliminary

95% conf. level

  • Run I:

L = 94  5 pb-1

Events observed = 5

Expected Background = 5.34  0.07

  • Run II:
  • (Fast simulation)
  • ’211=0.05

A0 = 0 ;  < 0 ; tan  = 1.5

Déliot et al., EPJ C 19 (01) 155

Auguste Besson for D0 collab.

slide32

e1

e2

e3

ET = 17.9 GeV

pT = 0.52 GeV

 = 0.43

 = 5.42

Charge= +1

ET = 13.9 GeV

pT = 10.9 GeV

 = -1.94

 = 2.80

Charge= +1

ET = 13.2 GeV

pT = 15.1 GeV

 = 1.06

 = 5.72

Charge= -1

me1e2 = 55.7

me1e3 = 10.8

me2e3 = 63.5

me1e2e3 = 85.2GeV/c2MET =10.7 GeV

eee candidate event

D Run 2 Preliminary

Trilepton eventsare classical SUSY signature

Electron

Electrons

Auguste Besson for D0 collab.

slide33

MET

e

1

2

pT = 28.2 GeV

 = -0.10

 = 6.20

Charge = -1

pT = 9.82 GeV

 = -1.48

 = 2.88

Charge = 1

ET = 19.2 GeV

 = 0.40

 = 0.63

No track match

m = 41.5 GeV/c2

MET =31.8 GeV

emm candidate event

D Run 2 Preliminary

D0 Run II preliminary

Muon system

Electron

Muon

Muon

Auguste Besson for D0 collab.

ee candidate event
ee candidate event

D0 Run II preliminary

Auguste Besson for D0 collab.

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