Searches for Supersymmetry at the Tevatron

1
Searches for Supersymmetry at the
Tevatron
Marie-Claude Cousinou CPPM-Marseille
Université de la Méditerranée For the D0 and CDF
collaborations

• Introduction
• Searches for Charginos and Neutralinos (RPC)
• Searches for Charginos, Neutralinos or Sleptons
  (RPV)
• Searches for Squarks and Gluinos (RPC)
• Searches for Squarks (RPV)
• Searches for Bs? ? ?-
• Conclusion

2
Tevatron at Fermilab Run II
Chicago ?
gt1 fb-1
CDF
DØ
Tevatron
?p source
Main Injector Recycler

• Higher energy
• (1.8 TeV ? 1.96 TeV) gt
• Higher cross sections
• Higher antiproton intensity
• 6?6 ? 36 ? 36 bunches(3.5 ?s ? 396 ns)
• antiproton recycler gt Higher luminosity
• RunII goal ?9 fb-1 in 2009

3
D0 CDF
Both general purpose detectors well understood
and highly efficient with Excellent
calorimeters and muon chambers coverage
Precision tracking (Silicon Vertex
Detector) Analyses presented here use up to ??390
pb-1
4
Some SUSY parameters reminder

• Every SM particle has ?S ½ partner
• R(-1)3B2LS 1 (SM) -1 (SUSY)
• LSP is stable if R parity is conserved (RPC)
• Small violation of R parity is not excluded
  (RPV)gt additional couplings and LSP
• decays in SM particles
• SUSY breaking Mechanisms 2 models
  treated here
• Graviton mediated model (mSUGRA)
  Gauge mediated model ( GMSB )
  
  
  
  ?
  (new chiral
  supermultiplets messengers)
• mo common scalar mass
  ? SUSY breaking scale
• m1/2 common gaugino mass
  Mm messenger mass (2 ?)
• tan ? ratio of Higgs Vacuum expectation
  Values N5 number of messengers
• sign(?) sign of Higgsino mass term
  tan ? and sign(?)
• A0 trilinear coupling
  Cgrav factor
  multiplying effective mass of ? ? ?
  
  gravitino
• LSP
  LSP
  NLSP

5
Charginos and Neutralinos in 3 leptons Etmiss
Final state 3 leptons large Etmiss Clean
signature but small event rates (?xBrlt0.5pb) and
leptons with low PT
6 analyses
ee or ? ? or e ? (PT cuts ?10 GeV) or e ?
or ? ? (had.decay of the ? NN) lepton
(isolated high quality track with PT cut ? 5
GeV) or 2 ? like sign (PT cuts ?10GeV) ETmiss
gt 22GeV anti Z cuts
6
Search for Charginos and Neutralinos in 3 leptons
ETmiss
??l
Channel Observed SM expected
e e l 0 0.21?0.12
e ? l 0 0.31?0.13
? ? l 2 1.75?0.57
Same sign ? ? 1 0.66?0.37
Sum 3 2.93?0.54?57
e ? l 0 0.58?0.14
? ? l 1 0.36?0.13
eel
??l
7
mSUGRA Search for Charginos and Neutralinos
hep-ex/0504032 analyses eel,
??l, e?l,????
? x Br(3l) is mainly a function of
and

• 3l-max low m0 - leptonic BR is
• maximally enhanced for
• heavy-Squarks
• cross section is maximal
• large m0 large
• W/Z exchange graph is dominant small
  leptonic BR

• Including the e?l and ??l analyses gives better
  sensitivity
• limit improves by 10 for tan?3
• more expected at large tan?, where the ?s
  dominate the final state

8
Charginos and Neutralinos in 3 leptons Etmiss
2 analyses ee l
PT(e1,e2) GeV PT(l3) GeV ETmiss GeV Lumi pb-1 SM exp. Obs.
High PT gt (20,8) e or ? gt (4) gt15 346 0.16??0.07 0
Low PT gt (10,5) track gt (4) gt15 224 0.36??0.27 2
m0 100 GeV, m1/2 180GeV, tan(?)5, ?gt0
0.5 events
High PT
? channel will be include soon
Low PT
9
GMSB Chargino and Neutralino in ?? ETmiss
(263 pb-1) (202 pb-1) Combination
hep-ex/0504004
D0/CDF Selection 2 photons ET(?)gt 20 / 13
GeV ETmiss gt 40 / 45 GeV
Obs Exp. SM M(??) (GeV)
D0 2 3.7?0.6 gt195
CDF 0 0.3?0.1 gt167
M(??)gt209 GeV/c2 M(?0)gt114 GeV/c2
Mm2?, N51, tan?15,? gt0
10
Production of a pair of CMSP (stable or ??)

• Charged Massive Particles with c??gt10m
• appear as slow moving high PT ?
• PTgt15 GeV isolation
• timing of the muon scintillators used
• Speed significantly slower than c
• 0 candidate expected 0.66?0.6event
• no SM background

(1-speed)/?speed
Limits GMSB CMSP is
not sensitive yet AMSB CMSP is
( ) Higgsino-like Gau
gino-like
gaugino-like
?limit0.06-0.62 pb
11
R-parity violation RPV
Additional terms in the superpotential
Li (Qi) are the lepton(quark) SU(2)L doublet
superfields Ej (Dj ,Uj) are the electron (down
and up quark) SU(2)L singlet superfield ,
, are Yukawa couplings
RPV consequences on experimental signatures

• RPV decay of LSP ( )
• ?ijk coupling Lifetime of LSP
• Resonant sparticle production
• ?ijk coupling

• SUSY signature can be very different
• Less missing ET
• More leptons and jets
• Sparticle may be produced by RPV couplings as
  single Sparticle

12
RPV ?ijkLiLjEk coupling
The couplings considered ?121 ? eeee, eee?
or ee?? ?? ?122 ? ????, ???e or ??ee ?? ?133
? ????, ???e or ??ee ??
?133
Selection 3 isolated leptons low PT
cut on 3rd lepton loose ETmiss cuts
Lumi. Int. (pb-1) Data SM exp. parameters (GeV)
eel (le, ?) 238 0 0.5?0.4 m0250 GeV,tan?5,A00, ?gt0 181
??l (le, ?) 160 2 0.6?1.9 m0250 GeV,tan?5,A00, ?gt0 165
ee?had 200 0 1.0 ?1.4 m080 GeV,tan?10,A00, ?gt0 118
13
RPV ?211L2Q1D1 coupling
,
the invariant masses of the and can
be reconstructed
2 jets and 2 isolated ? and PT (jet,?)20
GeV efficiency 0.5-0.6
A00, tan?2, sgn(?)-1
2 (data) / 1.1 ? 0.4 SM
14
RPV Search for Scalar Neutrino (1)
e (ETgt20 GeV) ? (PTgt20 GeV) opposite
charged Acceptance 25 (M(e ?) 350 GeV) Mass
resolution 15 GeV for M(e ?)300 GeV Data 77
events - SM exp. 71.3?1.8(stat) with M(e
?)gt100 GeV Data5 events - SM
exp.8.0?1.1(stat)
? BR
?1320.05 ?3110.16
M(e?) TeV
M(e?) TeV
15
RPV Search for Scalar Neutrino (2)
q
l -
q
Channel Cuts (GeV) Obs. SM exp. (GeV)
ee ET(e)gt25 M(ee)gt500 0 0.5 ? 0.1 725
?? PT(?)gt20 M(??)gt500 1 1.2 ? 0.1 725
?h? PT(?h)gt25 ETmissgt15 Mvisgt120 4 2.8 ? 0.5 377

Limit at 95CL If ?2Br 0.01

ee
??
16
Squarks and Gluinos
intermediate m0
low m0


high m0
mo 310 pb-1 jets (PT GeV) HT?Ptjet (GeV) ETmiss (GeV) Exp. SM Obs.
Low values 2 jets (60,50) gt250 gt175 12.8?5.4 12
Int. values 3 jets (60,40,25) gt325 gt100 6.1?3.1 5
High values 4 jets (60,40,30,25) gt250 gt75 7.1?0.9 10

254 pb-1 3 jets (125,75,25) gt350 gt165 4.2?1.1 3
17
mSUGRA Squarks Gluinos in jets ETmiss

• Enormous QCD background !
• Missing ET mis-measurements
• Jet energy mis-measured
• Beam halos-hot towers
• after ETmiss cleaning cuts

No charged leptons ETmiss non aligned with
jets Data 3 SM exp. 4.2?1.1 events Expect
0.7 - 4.8 events for M(q,g)380 GeV
18
mSUGRA Squarks Gluinos in jets ETmiss
(m0,m1/2)(500,80) GeV
QCD
4 jets analysis
m(squark) ? 318 GeV (m0 25 GeV) m(gluino) ? 233
GeV (m0 500 GeV) m(gl)m(sq) gt 333 GeV
19
Search for Gluino decaying in Sbottom Bottom
At least 3 jets ETgt15 GeV ETmiss gt 80 GeV
angular cuts between jets and ETmiss
Obs. Exp. SM
Excl. Single b tag 21 16.4 ? 3.7
Incl. double b tag 4 2.6 ? 0.7
95 C.L
20
Direct Production of decaying in
Selection 2 jets acoplanars (3rd jet) ETmiss
cut single b-tag lepton veto
M( ) Low val. Med.val. High val.
ET(j1,j2) (GeV) gt(40,15) gt(40,15) gt(70,40)
ETmiss (GeV) gt60 gt80 gt100
Data 36 15 2
SM exp. 38.6?2.8 19.6?1.7 4.4?0.4
21
RPC Search for pair production of Stop
If is the lightest
2 jets ET ? 35,25 GeV ETmiss ? 55 GeV e.g
anti QCD back to back jets no isolated lepton
pTe,? ? 10 GeV, anti ? double
heavy-flavor-tagging
11 (data) / 8.3 ? 2.0 SM
Limit from CDF RunI (88pb-1)
for Due to Higher ETmiss trigger
threshold and larger systematic uncertainties
Jet Energy Scale correction (6-33) Tagging
heavy flavor jets (13)
22
RPV Search for Stop decaying in b ?
?333
Search for
BR( ) ? 100
Selection 1l (le, ? PTgt10GeV) 1?had?(PTgt15GeV)
? 2 jets MT(l,ETmiss) lt 35 GeV ( to
remove W)
e? ?? all
Exp. SM 2.6?0.6 2.2?0.5 4.8?0.7
observed 2 3 5
23
Bs ? ??-
In SM, small BR 3.5 10?9 but in SUSY,
enhancement (tan?)6 factor

• Select ??- (PTgt 2-3GeV) from displaced
  vertices
• Count events inside a M(??) mass window (?100MeV
  around the BS mass)
• ?0 event
• Normalize the upper limit to the number of
• B ? J/? K? events

at 90C.L Lum. (pb-1) BR(Bs ? ??-)
364 lt 1.5 10-7
300 lt 3.0 10-7
.
24
Conclusions

• CDF and D0 have both covered many SUSY particles
  searches using an integrated luminosity of about
  350pb-1
• Substantial improvement wrt Run I
• Limits above LEPs in certain parameters space
  
• We are now analysing the 1 fb-1 data, hoping for
  a discovery ,
• otherwise there will be substantial improvement
  of the limits (see the Tevatron Connection
  Workshop talks (June 24-25))