Searches for Supersymmetry at the Tevatron
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Transcript Searches for Supersymmetry at the Tevatron
Searches for
Supersymmetry at the
Tevatron
looking for chargino and
neutralino
Oxford HEP Seminar
Tuesday 25th April 2006
Giulia Manca,
University of Liverpool
“Supersymmetry”,
by Karl Hager
From the artist’s
website:
“…I try to leave the
intention minimized
while maintaining an
element of exploratory
desperation.”
http://www.cassetteradio.com/cubagallery/hagen.htm
2
Outline
• Supersymmetry
• The Tevatron and its
•
•
•
experiments
Searching for Chargino
and Neutralino
Conclusions
Outlook
25th April 2006
Giulia Manca, University of Liverpool
3
Supersymmetry: All you need to
know
Extends the Standard Model (SM) by predicting a new symmetry:
spin-1/2 matter particles (fermions) <=> spin-1 force carriers (bosons)
Standard Model Particles
Susy Particles
g
Higgsino
Higgs
Higgs
e
e
~
G~
G
Gravitino
G
Graviton
Quarks
25th April 2006
Leptons
Force particles
Squarks
Sleptons
Susy
Force particles
Giulia Manca, University of Liverpool
4
Supersymmetry: All you need to
know
Extends the Standard Model (SM) by predicting a new symmetry:
spin-1/2 matter particles (fermions) <=> spin-1 force carriers (bosons)
Standard Model Particles
Susy Particles
g
Higgsino
Higgs
Higgs
e
e
~
G~
G
Gravitino
G
Graviton
Quarks
25th April 2006
Leptons
Force particles
Squarks
Sleptons
Susy
Force particles
Giulia Manca, University of Liverpool
5
Supersymmetry: All you need to
know
Extends the Standard Model (SM) by predicting a new
symmetry:
spin-1/2 matter particles (fermions) <=> spin-1 force carriers (bosons)
Standard Model Particles
Susy Particles
g
Higgsino
~0
Higgs
Higgs
ci
e
e
4 neutralinos
~c
i
2
~ charginos
G~
G
Gravitino
G
Graviton
Quarks
Leptons
Force particles
Squarks
Sleptons
New Quantum Number R-Parity Rp (1)BL2s
Lightest Sparticle (LSP) stable!
25th April 2006
Susy
Force particles
+1 (SM particles)
-1 (Susy particles)
Giulia Manca, University of Liverpool
6
•
Supersymmetry: models
Different mechanisms of susy breaking lead to different models
Model
MSSM
Name
Breaking mechanism
and scale
Minimal
Supersymmetric
Standard Model
Parameters
LSP
>100
any…
mSugra, Minimal
cMSSM Supergravity
Constrained MSSM
Gravity (GUT)
M0,M1/2,
A0,tan
sgnor
c0
GMSB
Gauge Mediated
Symmetry
Breaking
Gauge messengers
(10 TeV)
m,Mm, tan,
N5, sgn(),
Cgrav
Graviti
no (G)
AMSB
Anomaly Mediated
Symmetry
Breaking
“conformal anomaly”
M3/2,m0,tan
sgn
c0
If RP not conserved, LSP decays into SM particles (RPV models)
25th April 2006
Giulia Manca, University of Liverpool
7
Supersymmetry: All you need to
know
Extends the Standard Model (SM) by predicting a new symmetry:
spin-1/2 matter particles (fermions) <=> spin-1 force carriers (bosons)
Standard Model Particles
Susy Particles
g
Higgsino
~0
Higgs
Higgs
ci
e
e
4 neutralinos
~c
i
2
~ charginos
G~
G
Gravitino
G
Graviton
Leptons
Quarks
Force particles
Squarks
~
Sleptons
Susy
Force particles
1. mSugra and AMSB: c0 LSP, stable
~
2. GMSB: G LSP,stable
3.
LSP decays into SM particles
25th R
April
2006
p (RPV):
Giulia Manca, University of Liverpool
8
Supersymmetry: why ?
•Solves “Hierarchy Problem”
•Provides Grand Unification
Standard Model
SUSY
Theory at the 1016 GeV scale
•Consistent with results from
Precision Data fits
New
Top
Mass
172.5
GeV/c2
25th April 2006
•Rp Conserving models
provide good Dark Matter
Candidate (LSP)
Giulia Manca, University of Liverpool
9
•
Supersymmetry & Dark Matter
Evidence for Dark Matter
galaxy rotation
fluctuations in the cosmic
In mSugra and with Rp
conserved and EW radiative
corrections,
5 main regions where neutralino
fulfills the WMAP relic density
•bulk region (low m0 and m1/2)
•stau coannihilation region mc mstau
Common gaugino mass M1/2
•
microwave background (WMAP)
From WMAP: CDMh2 ≤ 0.113
•hyperbolic branch/focus point (m0 >> m1/2)
•funnel region (mA,H 2mc)
•Higgs pole: 2mc0mh
25th April 2006
Common
scalar
Mof0 Liverpool
Giulia
Manca,mass
University
10
•
Supersymmetry & Dark Matter
HOWEVER: MORE OPTIONS
WITH LESS CONSTRAINED
MODELS
Evidence for Dark Matter
galaxy rotation
fluctuations in the cosmic
•
H. Baer, A. Belyaev, T.
Krupovnickas, J. O’Farrill,
JCAP 0408:005,2004
microwave background
(WMAP)
In mSugra and with Rp
conserved and EW radiative
corrections,
4 main regions where
neutralino fulfills the
WMAP relic density
M1/
2
•bulk region (low m0 and m1/2)
•stau coannihilation region mc mstau
•hyperbolic branch/focus point (m0 >> m1/2)
•funnel region (mA,H 2mc)
25th April 2006
M0
Giulia Manca, University of Liverpool
11
Supersymmetry: how ?
Wide range of signatures: look for SuSy specific signatures or
excess in SM ones; examples:
Rp
:
LSP Large Missing Energy ET
:
Isolated leptons
c0
˜ g˜ Multijets
qc±
GMSB:
2 LSPs Diphotons
1012
Remember :
VERY SMALL cross sections !!
25th April 2006
(fb)
104
10
Giulia Manca, University of Liverpool
12
The Tevatron
•
p p at ECM 1.96 TeV
•
High Luminosity
Tevatron ~1.5 fb-1!
CDF and D0 running at
high efficiency
Still long way to go!
design goal
We are
here
Mar01-Aug05
750 pb-1
25th April 2006
base goal
Giulia Manca, University of Liverpool
Charginos and Neutralinos
14
Why Charginos and Neutralinos ?
• They are light (~ 100-500 GeV/c2)
Squarks and gluinos too heavy for the Tevatron
• They decay giving striking signatures
In mSugra : 3 isolated leptons + /
ET
In GMSB : 2 photons +/
ET
In AMSB : long-lived particles
In R
/p models : >3 leptons
(and many more signatures in each model
depending on the parameters !)
25th April 2006
Giulia Manca, University of Liverpool
15
The trilepton signal
Higgsinos and
gauginos mix
CHARGINOS
NEUTRALINOS
Striking signature at Hadron Collider,
THREE LEPTONS
In mSUGRA Rp conserved scenario,
LARGE MISSING TRANSVERSE
ENERGY from the stable LSP+
Low background
Easy to trigger
~
c 10
~
c 1
p
p
~
c 20
~
c 10
GOLDEN SIGNAL AT THE
LOW MODEL DEPENDENCE TEVATRON !!
25th April 2006
Giulia Manca, University of Liverpool
16
mSugra Existing Limits : LEP
c0 c±0GeV/c2;
c00GeV/c2;
SM Higgs Limits
Slepton Limits
Chargino-Limits
LEP I Precision measurements
Theoretically forbidden
(i.e. M1(GUT)=M2(GUT)=M3(GUT)=m1/2)
25th April 2006
Giulia Manca, University of Liverpool
Chargino-Neutralino
production…
17
Low cross section
(weakly produced)
T. Plehn, PROSPINO
10
q
SUSY (pb) vs sparticle
mass(GeV/c2) for
√s=1.96 TeV
~
c 20
W*
1
~
c 1
q
t-channel
interferes
destructively
c0 c±
~
q
~
q
q'
10-1
c 20
~
c
1
10-2
10-3
100 150 200 250 300 350 400 450 500
Tevatron sensitive to the BULK
region in WMAP data
25th April 2006
Giulia Manca, University of Liverpool
18
…and decay
Leptons of 1st, 2nd
generation
are preferred
~
c
Chargino Decay
~
c
1
0
1
W*
Leptons of 3rd
generation
are preferred
~
c 1
~
~
c 10
Neutralino Decay
~
c 1
~
~
c 10
~
c 10
~
c 20
~
0
c2
Z*
25th April 2006
~
~
c 10
Best reach for the Tevatron
for mass sleptons~mass chargino
=> BR (3ℓ) enhanced
Giulia Manca, University of Liverpool
Trileptons at CDF
20
How to investigate the different scenarios?
CHANNEL
LUM
TRIGGER PATH
+ e/
750
High pT Single Lepton
ee + e/
350
High pT Single Lepton
+ e/
312
Low pT Dilepton
e + e/
Ongoing
Low pT Dilepton
e + e/
Ongoing
High pT Single Lepton
High tan
e/e + track
Ongoing
Low pT Dilepton
region
ee + track
610
Low pT Dilepton
ee,e,
710
High pT Single Lepton
Low tan
region
Acceptance
improvement
sensitive
to leptonic
decay
sensitive
to all
decays
Low tan scenario tan=5 , 38%
High tan scenario tan=20, 100%
High pT data-sample benchmark
to understand low pT data-sample
25th April 2006
Giulia Manca, University of Liverpool
21
How to investigate the different scenarios?
CHANNEL
LUM
TRIGGER PATH
+ e/
750
High pT Single Lepton
ee + e/
350
High pT Single Lepton
+ e/
310
Low pT Dilepton
e + e/
Ongoing
Low pT Dilepton
e + e/
Ongoing
High pT Single Lepton
High tan
e/e + track
Ongoing
Low pT Dilepton
region
ee + track
610
Low pT Dilepton
ee,e,
705
High pT Single Lepton
Low tan
region
Acceptance
improvement
sensitive
to leptonic
decay
sensitive
to all
decays
Low tan scenario tan=5 , 38%
High tan scenario tan=20, 100%
High pT data-sample benchmark
to understand low pT data-sample
25th April 2006
Giulia Manca, University of Liverpool
22
Event kinematic
Leading lepton
Next-To-Leading lepton
Third lepton
0
0
pT m m( c 2 ) m( c1 )
Chargino and Neutralino
Lepton pT (GeV)
Typical SUSY leptons
Lepton pT thresholds
EWK range
high-pt analyses 20,8(10),5 GeV
prompt decay
Leptons
separated in space
low-pt analyses 15(5),5,4(5) GeV
25th April 2006
Giulia Manca, University of Liverpool
23
Finding SUSY at CDF
CENTRAL REGION
=0
=1
Muon system
e
Recover loss in
acceptance due
to cracks in the
detector if we
accept muons
with no hits in
the Muon
Chamber
Drift chamber
Missing Transverse Energy
(MET)
Real MET
Particles escaping detection ( )
Em
Calorimeter
25th April 2006
Fake MET
Had Calorimeter
Muon pT or jet ET mismeasurement
Additional interactions
Cosmic ray muons
Mismeasurement of the vertex
Giulia Manca, University of Liverpool
Backgrounds:
how
to
reduce
Backgrounds
them?
• DIBOSON (WZ,ZZ) PRODUCTION
• DRELL YAN PRODUCTION +
24
additional lepton
Leptons have high pT
Leptons have mainly high pT
Leptons are isolated and separated
Small MET
MET due to neutrinos
e
Low jet activity
The third lepton
originates from g
conversion
p
25th April 2006
• HEAVY FLAVOUR PRODUCTION
e
p
e
The third lepton is
a fake lepton
e
g
p
irreducible background
Leptons mainly have low pT
e
Leptons are not isolated
MET due to neutrinos
0
p
p
p
Giulia Manca, University of Liverpool
25
Analysis Strategy
COUNTING EXPERIMENT
• Optimise selection criteria for best
signal/background value;
• Apply selection criteria to the data
•
Define the signal region and keep it
blind
Test agreement observed vs.
expected number of events in
orthogonal regions (“control
regions”)
•
•Look in the signal region and
count number of SUSY events !!
Or set limit on the model
25th April 2006
Giulia Manca, University of Liverpool
26
Selection criteria: (I) Mass
Rejection of J/, and Z
Dimuon events
Dimuon Mass(GeV/c2)
M<76 GeV & M >106 GeV
M> 15 (20,25) GeV
min M < 60 GeV
25th April 2006
(dielectron+track analysis)
Giulia Manca, University of Liverpool
27
(II) DeltaPhi( , ) + Jet Veto
Rejection of DY and high jet
multiplicity processes
Analysis
Kinematic
Variable
Kinematic
Cut
Trilepton
analyses
Jet ET > 20
GeV
n. Jets < 2
Dielectron +
track analysis
HT= ∑jetETj
HT < 80 GeV
25th April 2006
Giulia Manca, University of Liverpool
28
(III) MET selection
Further reducing DY by MET > 15 GeV
…Still BLIND !
25th April 2006
Giulia Manca, University of Liverpool
30
Understanding of the Data
-like sign
L=704 pb-1
MET
Each CONTROL REGION is investigated
with different jet multiplicity-check NLO processes
with 2 leptons requirement - gain in statistics
with 3 leptons requirement - signal like topology
??
EWK
Diboson
low DY
Zmass
L=704 pb-1
10
15
SIGNAL
REGION
DY + g
15
25th April 2006
Z + fake
76
Invariant Mass
106
Very good agreement between SM prediction
observed
Giulia and
Manca,
University data
of Liverpool
31
Systematic uncertainty
Major systematic uncertainties affecting the
measured number of events
ee+lepton (high-pt)
Signal
Lepton ID 5%
Z->ee MC
Muon pT resolution 7%
Background
Fake lepton estimate method 5%
Jet Energy Scale 22%
Common to both signal and background
Luminosity 6%
Theoretical Cross Section 6.5-7%
PDFs 7%
25th April 2006
Giulia Manca, University of Liverpool
32
Results !
Look at the “SIGNAL” region
Analysis
Total
predicted
background
Example
SUSY
Signal
Observed
data
ee,e,
6.801.00
3.180.33
9
+e/
(low-pT)
0.130.03
0.170.04
0
ee+track
0.480.07
0.360.27
1
ee + e/
0.170.05
0.490.06
0
+e/
0.640.18
1.610.22
1
e +e/
0.780.15
1.010.07
0
25th April 2006
Giulia Manca, University of Liverpool
33
Highest lepton-pt event
In the ee like-sign analysis, we observe one interesting event
e- : 103 GeV
Mass OS1
220 GeV/c2
Mass OS2
12 GeV/c2
MET : 25 GeV
e+ : 5 GeV
e- : 107 GeV
g : 15 GeV
25th April 2006
Giulia Manca, University of Liverpool
34
Limit
No SUSY :(
•Combined all analyses to
obtain a limit on the mass
of the chargino in mSugralike scenario with no
slepton mixing
• Observed limit:
M(c1) ~ 127 GeV/c2
xBR ~ 0.25 pb
• Sensitive up to masses
M(c1) ~ 140
2
GeV/c
xBR ~ 0.2 pb
• Better than LEP and
Tevatron Run I
25th April 2006
Giulia Manca, University of Liverpool
35
Limit
But : we are model
dependent !
In “standard” mSugra
Sensitive to chargino
masses of ~ 116 GeV/c2
Not able to exclude this
particular region of
parameter space with
these results …
25th April 2006
Giulia Manca, University of Liverpool
Trileptons at DO
37
DO detector
•Coverage to muons up to eta~2
=0
=1.0
=2.0
=1.0
=3.0
=3.6
25th April 2006
Giulia Manca, University of Liverpool
38
Chargino and Neutralino in 3+ET
In mSUGRA:3 leptons+ET
Luminosity ~350 pb-1
Use tau leptons
6 analyses:
-2l(l=e,,)+isolated track or
ET and topological cuts (M,f, MT)
Selection
SM expected
OBSERVED
ee+t
0.21±0.12
0
et
0.31±0.13
0
t
1.75±0.57
2
±±
0.64±0.38
1
e+t
0.58±0.14
0
+t
0.36±0.13
1
SUM
3.85±0.75
4
25th April 2006
M(e (GeV/c2)
Giulia Manca, University of Liverpool
39
Chargino Neutralino Limits
mSUGRA: M(c±)≈M(c02) ≈2M(c01)
“3l-max”
•
•
M( ) > M(c02)
No slepton mixing
Limits :
xBR < 0.2 pb
M(c±1)>116 GeV/c2
mSugra
optimistic
scenario
A0=0
“Heavy Squarks”
M(c±)≈M(c02)3M(q)
xBR < 0.2 pb
M(c±1)>128 GeV/c2
•
“Large m0”
M()>>M(c02 ,c±)
No sensitivity
•
25th April 2006
Start testing above LEP limit for
mSUGRA-but LEP Model Independent !!
Giulia Manca, University of Liverpool
40
Summary and Outlook:
Chargino and Neutralino in mSugra
TRILEPTONS SIGNAL:
• CDF and D0 analysed first half of data and observed no excess :(
• Set limit already beyond LEP results ! (although model dependent )
• 1.5 fb-1 of data collected and ready to be analysed
• With 4-8 fb-1 by the end of RunII we should be sensitive to Chargino
masses up to ~250 GeV and xBR ~ 0.05-0.01 pb !!
Ellis, Heinemeyer, Olive, Weiglein,
hep-ph\0411216
Favoured
by EW
precision
data
25th April 2006
Giulia Manca, University of Liverpool
Charginos and Neutralinos
in GMSB
42
Why Charginos and Neutralinos ?
• They are light (~ 100-500 GeV/c2)
Squarks and gluinos too heavy for the Tevatron
• They decay giving striking signatures
In mSugra : 3 isolated leptons + /
ET
In GMSB : 2 photons +/
ET
In AMSB : long-lived particles
In R
/p models : >3 leptons
(and many more signatures in each model
depending on the parameters !)
25th April 2006
Giulia Manca, University of Liverpool
43
Motivation: Run I CDF Event
• Run I event:
2 e, 2 g and Et=56 GeV
SM expectaction: 10-6 Events
• Interpretations in GMSB:
Selectron
Chargino/Neutralino
• Visible in inclusive diphoton
•
Et spectrum
Searched by Tevatron Run II,
LEP and HERA
Phys.Rev.Lett.81:1791-1796,1998
25th April 2006
Giulia Manca, University of Liverpool
44
Chargino Neutralino in gg+ET
In GMSB: 2 photons+ET
D0(CDF) Event selection:
-2 photons ET -> 20(13) GeV
-ET>40(45) GeV
SM Expected
OBSERVED
D0
3.7±0.6
2
CDF
0.3±0.1
0
CDF‡ and D0#
combined result:
m(c±)>209 GeV/c2
‡Phys.Rev.D.71,3 031104(2004)
#Phys. Rev. Letters 94,
041801(2005)
25th April 2006
Giulia Manca, University of Liverpool
45
Chargino Neutralino in gg+ET
In GMSB: 2 photons+ET
D0 Event selection (L=760
-2 photons ET -> 25 GeV
-ET>45GeV
25th April 2006
pb-1):
D0
SM Expected
OBSERVED
2.1±0.7
4
D0 new result :
m(c±)>220 GeV/c2
Giulia Manca, University of Liverpool
Charginos and Neutralinos
in AMSB
47
Why Charginos and Neutralinos ?
• They are light (~ 100-500 GeV/c2)
Squarks and gluinos too heavy for the Tevatron
• They decay giving striking signatures
In mSugra : 3 isolated leptons + E
/T
In GMSB : 2 photons +/
ET
In AMSB : long-lived particles
In R
/p models : >3 leptons
(and many more signatures in each model
depending on the parameters !)
25th April 2006
Giulia Manca, University of Liverpool
48
Charginos in AMSB
In the AMSB scenario (c01 LSP)
• c±1 is the NLSP (Next-to-Lightest-Supersymmetric Particle)
• lives long enough to decay outside the detector;
•c and the BR depend almost entirely upon the mass difference c±1-c01
c±1-> c01
25th April 2006
M(
Giulia Manca, University of Liverpool
49
Champs
CHArged Massive stable Particles:
-electrically charged
-massive->speed<<c
-lifetime long enough to decay
outside detector
Event Selection:
-2 muons Pt> 15 GeV, isolated
-Speed significantly slower than c
100 GeV Staus
100 GeV Higgsino-like
Chargino
100 GeV Gaugino-like
Chargino
No SM Background!!->from DATA
Expected
OBSERVED
0.66±0.06
0
Limits in AMSB:
champ = ~
c±
~±
M(c
1)>174
GeV/c2
25th April 2006
Giulia Manca, University of Liverpool
Charginos and Neutralinos
in Rp violating
51
Why Charginos and Neutralinos ?
• They are light (~ 100-500 GeV/c2)
Squarks and gluinos too heavy for the Tevatron
• They decay giving striking signatures
In mSugra : 3 isolated leptons + /
ET
In GMSB : 2 photons +/
ET
In AMSB : long-lived particles
In R
/p models : >3 leptons
(and many more signatures in each model
depending on the parameters !)
25th April 2006
Giulia Manca, University of Liverpool
52
•
R Parity Violation
RPV tested in Production and Decay of SUSY particles
-d
d
´211
~
c01 ~+
~
´211
u
-u
Resonant sparticle
production
-> ’ijk coupling
Selection:
2jets+2isolated ’s
’211
25th April 2006
133
122
RPV decay of LSP(c01)
-> ijk coupling
Selection:
3 (=e,)+ET+channel
dependent cuts
121 ->(eeee,eee,ee+
122 ->(,e,ee) +
Giulia Manca, University of Liverpool
53
•
RPV Neutralino Decay
Model:
R-parity conserving production => two
•
•
neutralinos
R-parity violating decay into leptons
One RPV couplings non-0: 122 , 121
Final state: 4 leptons +Et
eee, ee, e,
3rd lepton Pt>3 GeV
Largest Background: bb
Obs.
Exp.
eel (l=e,)
0
0.5±0.4
l (l=e,)
2
0.6+1.9-0.6
Interpret:
M0=250 GeV, tan=5
121>0
122>0
~
m(c+1) >165 GeV
25th April 2006
~
m(c+1) >181 GeV
Giulia Manca, University of Liverpool
54
•
RPV Neutralino Decay
Model:
R-parity conserving production => two
neutralinos
R-parity violating decay into leptons
One RPV couplings non-0: 122 , 121
•
Final state: 4 leptons +Et
•
Interpret:
~+ ) >199 GeV
m(c
1
eee, ee, e,
3rd lepton Pt>5 GeV
Largest Background: DY+conversion
M0=250 GeV, tan=5
Obs.
Exp.
eel (l=e,)
5
4.3±0.4
l (l=e,)
1
3.8 ±0.4
25th April 2006
122>0
121>0
~
m(c+1) >172.6 GeV/c2
Giulia Manca, University of Liverpool
55
•
Non-collider LSP searches
DAMA, CDMS,
Edelweiss,..
Direct LSP detection
through nuclear recoil
Indirect searches:
• Icecube/Antares: indirect
search for neutrinos from
LSP annhiliation in the
Sun
• Glast/Egret: detect g from
XX->qq,WW,ZZ->had,
•
•
andgg
Pamela/AMS-02/HEAT:
detect e+’s from heavy q,
leptons and bosons from
LSP annihil.
BESS: detect antiprotons
25th April 2006
Giulia Manca, University of Liverpool
56
•
Chargino-Neutralino: Present
Lots of searches setting limits on c0(+) masses from
different sides
c0 c±
Rp
M(c±)>199
•
•
AMSB
M(c±)>174 GMSB
M(c±)>220
mSugra
M(c±)>127
Getting close to the most favoured masses!
Still ~1 fb-1 to analyse ! => Observation ? Or better limits…
Hints from the Tevatron will help LHC to prioritise searches
25th April 2006
Giulia Manca, University of Liverpool
57
The most favoured masses in
mSugra
Simultaneous variations of M0, M1/2,tan
constraining mtop,mb s and using input
measurements of b->sg, (g-2),DMh2,
get the most probable mSugra spectrum
25th April 2006
hep-ph/0507283
mtop
= 174.3±3.4 GeV/c2
mb(mb)MS = 4.2±0.2 GeV/c2
s(Z)MS =0.1187 ± 0.002
BR(b->sg) = 3.52±0.42x10-9
DMh2
= 0.1126±0.009,
-10
(g-2)Giulia
/2 =Manca,
19.0 University
± 8.4x10
of Liverpool
What about the future ?
59
•
•
•
Susy at the LHC !
Will generally be found fast!
But SUSY comes in very many
flavours
Hints from the Tevatron would
help on search priorities, e.g.
tan large:
3rd generation important
(’s, b’s)
R-parity is violated
No ET
GMSB models:
Photons important
Split-SUSY:
Stable charged hadrons
Can setup triggers accordingly
25th April 2006
Giulia Manca, University of Liverpool
Chargino and Neutralino at the
LHC
60
•
In mSugra:
squark-gluino dominate
•
(pb)
SUSY (pb) vs sparticle
mass(GeV/c2) for √s=14 TeV
(jets+met channel)
T. Plehn, PROSPINO
300k
events
in 3fb-1
Direct production crosssections small
But could be the only way
•
to observe SUSY if
quark-gluinos are heavy
! (“focus point”)
In other regions trileptons
signal enhanced from
squark-gluino cascade
3,000
events
in 3fb-1
0
c c±
mass(GeV/c2)
But also :
6x106 Zs, 2.4x106 t-antitop and
150,000 WZ !
25th April 2006
Giulia Manca, University of Liverpool
61
Building on leptons…
• Other possibilities with lepton
signatures in mSugra:
Jets+MET+leptons -> mass of the
sparticles in the cascade
Like-sign dileptons -> still sensitive to
chargino-neutralino but also on gluino pair
production ! (no jet veto)
R-parity violating scenarios
25th April 2006
Giulia Manca, University of Liverpool
62
Conclusions
• Chargino-neutralino are the golden
•
•
discovery mode at the Tevatron in virtually
all the models
Hints from the Tevatron can give
directions to the LHC
At the LHC, chargino-neutralino
production crucial in study the properties
of the new sparticles as their masses (but
only mSugra considered)
• Exciting times to come !!
25th April 2006
Giulia Manca, University of Liverpool