Transcript Searches for Supersymmetry at the Tevatron

Searches for
Supersymmetry at the
Tevatron
Liverpool HEP Seminar
Thursday 15th December 2005
Giulia Manca,
University of Liverpool
“Supersymmetry”,
by Karl Hager
From the artist’s
website
http://www.cassetteradio.co
m/cubagallery/hagen.htm
“…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
15th December 2005
Giulia Manca, University of Liverpool
3
•
Supersymmetry: Introduction
New symmetry fermions-bosons:
 SM fermion  SUSY boson
•
 SM boson  SUSY fermion
Ideated to cancel quadratic divergencies in the Higgs self
coupling energy
~
f
f
H
H
f
•
H
~
f
H
Sparticles not observed in nature => Susy must be broken!
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Giulia Manca, University of Liverpool
4
•
Supersymmetry: models
Different mechanisms of susy breaking lead to different
models
Name
Model
Breaking
mechanism and
scale
Parameters
MSSM
Minimal Supersymmetric
Standard Model
>100
mSugra,
cMSSM
Minimal Supergravity
Constrained MSSM
Gravity (GUT)
M0,M1/2, A0,tan
sgnor
GMSB
Gauge Mediated
Symmetry Breaking
Gauge
messengers (10
TeV)
m,Mm, tan, N5,
sgn(), Cgrav
AMSB
Anomaly Mediated
Symmetry Breaking
“conformal
anomaly”
M3/2,m0(other
term),tansgn
Determines the SUSY Mass spectrum!
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Giulia Manca, University of Liverpool
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Supersymmetry: particles
g
c0 i
4 neutralinos
ci
~
G
G
R-Parity Quantum Number-> R p  (  1)
B  L  2s
1. mSugra and AMSB: c01 LSP, stable
2 charginos
+1 (SM particles)
-1 (Susy particles)
~
2. GMSB: G LSP,stable
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3. Rp (RPV): LSP decays into SM particles
Giulia Manca, University of Liverpool
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Supersymmetry: why ?
•Solves “Hierarchy Problem”
•Provides Grand Unification
Theory at the 1016 GeV scale
•Consistent with results from
Precision Data fits
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New
Top
Mass
172.7
GeV/c2
•Rp Conserving models provide
good Dark Matter Candidate
(LSP)
Giulia Manca, University of Liverpool
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•
Supersymmetry & Dark Matter
Evidence for Dark Matter
 galaxy rotation
 fluctuations in the cosmic
•
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
(GeV)
•bulk region (low m0 and m1/2)
•stau coannihilation region mc  mstau
•hyperbolic branch/focus point (m0 >> m1/2)
•funnel region (mA,H  2mc)
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M0(GeV)
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•
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)
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M0
Giulia Manca, University of Liverpool
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Supersymmetry: how ?
Wide range of signatures: look for SuSy specific signatures or
excess in SM ones; examples:
Rp
:
LSP
:
c0
c±
q˜ g˜
GMSB:
2 LSPs
Large Missing Energy ET
Isolated leptons
Multijets
Diphotons
Remember :
VERY SMALL cross sections !!
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(fb)
1012
104
10
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The Tevatron
•
p p at ECM 1.96 TeV
•
High Luminosity
 Tevatron 1 fb-1!
CDF and D0 running at
high efficiency
Still long way to go!
design goal
Mar01Jul04
base goal
350pb-1
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Giulia Manca, University of Liverpool
Charginos and Neutralinos
12
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 !)
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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 !!
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Giulia Manca, University of Liverpool
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Existing Limits : LEP
SM Higgs Limits
Slepton Limits
Chargino-Limits
LEP I Precision measurements
Theoretically forbidden
(i.e. M1(GUT)=M2(GUT)=M3(GUT)=m1/2)
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15th December 2005
ADLO exclusion plots
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Chargino-Neutralino
production…
16
 Low cross section
(weakly produced)
T. Plehn, PROSPINO
10
q
SUSY (pb) vs sparticle
mass(GeV/c2) for
√s=1.96 TeV
~
c2
0
W*
~

c1
q
t-channel
interferes
destructively
1
c0 c±1
~
q
~
q
q'
10-1
0
10-2

1
10-3
c2
~
c
100 150 200 250 300 350 400 450 500
Tevatron sensitive to the BULK
region in WMAP data
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…and decay
Leptons of 1st, 2nd
generation
are preferred
~
c
Chargino Decay
~

1
c
0
1

W*
Leptons of 3rd
generation
are preferred


~

c1

~

~
c1
0

Neutralino Decay
~
c 1

~

~
c 10
~
c1
0

~
~
c2
0
 c2
0
Z*
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
~


~
c1
0
Best reach for the Tevatron
for mass sleptons~mass chargino
=> BR (3l) enhanced
Giulia Manca, University of Liverpool
Trileptons at CDF
19
How to investigate the different scenarios?
CHANNEL
STATUS
TRIGGER PATH
 + e/
reported
High pT Single Lepton
ee +/e
reported
High pT Single Lepton
 + e/
Ongoing
Low pT Dilepton
e + e/
Ongoing
High pT Single Lepton
e + e/
Ongoing
Low pT Dilepton
High tan
e + track
Ongoing
Low pT Dilepton
region
e + track
Ongoing
Low pT Dilepton
ee + track
reported
Low pT Dilepton
Low tan
region
Acceptance
improvement
sensitive
to leptonic 
decay
sensitive
to hadronic 
decay
Low tan scenario tan=5 , 38%
High tan scenario tan=20, 100%
High pT data-sample benchmark
to understand low pT data-sample
15th December 2005
Giulia Manca, University of Liverpool
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Event kinematic
Leading lepton
Next-To-Leading lepton
Third lepton
0
0
 pT  m  m ( c 2 )  m ( c 1 )
Chargino and Neutralino
Lepton pT (GeV)
Typical SUSY leptons
Lepton pT thresholds
EWK range
 trilepton analyses 20,8,5 GeV
prompt decay
Leptons
separated in space
 dielectron + track analysis 10,5,4 GeV
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Giulia Manca, University of Liverpool
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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
15th December 2005
Fake MET
Had Calorimeter
Muon pT or jet ET mismeasurement
Additional interactions
Cosmic ray muons
Mismeasurement of the vertex
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Backgrounds
Backgrounds
DRELL YAN PRODUCTION +
additional lepton
DIBOSON (WZ,ZZ) PRODUCTION
 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
The third lepton is
a fake lepton
p

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irreducible background
e
HEAVY FLAVOUR PRODUCTION 
e
g
p
e
 Leptons have high pT
p
 Leptons mainly have low pT
e
 Leptons are not isolated
 MET due to neutrinos
0

p
p
p


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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
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Giulia Manca, University of Liverpool
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Selection criteria: (I) Mass
Rejection of J/,  and Z
 Mll<76 GeV & Mll>106 GeV
 Mll>
# dimuon pairs
Dimuon events
15 GeV
 min Mll< 60 GeV
(dielectron+track analysis)
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(II) DeltaPhi(l,l) + Jet veto
Rejection of DY and high jet
multiplicity processes
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Analysis
Kinematic
Variable
Kinematic
Cut
Trilepton
analyses
Jet ET > 20
GeV
n. Jets < 2
Dielectron +
track analysis
HT= ∑jetETj
HT < 80 GeV
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(III) MET selection
Further reducing DY by MET > 15 GeV
Trilepton Analysis (muon based) L=346 pb-1
Kinematic Cut
Example
SUSY
Signal
TOT
BACKGROUND
Number of
trilepton events
0.480.02
2.850.27
Invariant Mass
0.420.02
1.060.18
Jet Multiplicity
0.420.02
1.040.18
MET
0.370.02
0.090.03
…Still BLIND !
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Giulia Manca, University of Liverpool
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Understanding of the Data
Each CONTROL REGION is investigated
 with different jet multiplicity to check NLO processes
 with 2 leptons requirement (gain in statistical power)
 with 3 leptons requirement (signal like topology)
MET
Trilepton Analysis (muon based) L=346 pb-1
??
Diboson
10
15
SIGNAL
REGION
DY + g
15
Z + fake
76
Invariant Mass
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106
Control
Region with 2

Total predicted
background
Observed
data
Z veto,
high MET,
n. Jets < 2
522  79
538
Z mass,
high MET,
n. Jets > 1
1.9  0.9
2
Z mass
window
3178 541
3168
Very good agreement between
Giulia Manca,
University
of Liverpool
SM prediction
and
observed
data
28
Systematic uncertainty
Major systematic uncertainties affecting the
measured number of events
 Signal
Z->ee MC
 Lepton ID 5%
 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%
15th December 2005
Giulia Manca, University of Liverpool
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Results !
Look at the “SIGNAL” region
Analysis
Total
predicted
background
Example SUSY
Signal
Observed
data
Trilepton (+l)
0.090.03
0.370.05
0
Trilepton
(ee+l)
0.170.05
0.490.06
0
Dielectron
+track
0.480.07
0.360.27
2
Details about the
dielectron + track analysis
15th December 2005
DY
WW/ZZ
WZ/g*
t-tbar
0.25
0.17
0.062
 0.024
0.032
0.005
0.010
0.007
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30
Candidate event ?
In the dielectron + track analysis, we observe one interesting event
Next-to-leading
e-, pT = 12 GeV
Isolated track, pT = 4 GeV
Muon?
15th December 2005
Leading electron
e+, pT = 41 GeV
MET, 45 GeV
Mass OS1
41.6 GeV
Mass OS2
27.0 GeV
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Trileptons at DO
32
DO detector
•Coverage to muons up to eta~2
=0
=1.0
=2.0
=3.0
=1.0
=3.6
15th December 2005
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Chargino and Neutralino in 3+ET
In mSUGRA:3 leptons+ET
 xBR~0.2 pb
 Very clean signature
 SM background very small !
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
et
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
15th
December 2005 3.85±0.75
4
M(e (GeV/c2)
Giulia Manca, University of Liverpool
34
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
•
15th December 2005
Start testing above LEP limit for
mSUGRA-but LEP Model Independent !!
Giulia Manca, University of Liverpool
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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 fb-1 of data collected and ready to be analysed M(c) <170 GeV)
• 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
15th December 2005
Giulia Manca, University of Liverpool
Charginos and Neutralinos
in GMSB
37
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 !)
15th December 2005
Giulia Manca, University of Liverpool
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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
15th December 2005
Giulia Manca, University of Liverpool
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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)
15th December 2005
Giulia Manca, University of Liverpool
Charginos and Neutralinos
in AMSB
41
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 !)
15th December 2005
Giulia Manca, University of Liverpool
42
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
M(
15th December 2005
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43
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± 1
~±
M(c
1)>174
GeV/c2
15th December 2005
Giulia Manca, University of Liverpool
Charginos and Neutralinos
in Rp violating
45
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 !)
15th December 2005
Giulia Manca, University of Liverpool
46
•
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
15th December 2005
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
47
•
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
122>0
15th December 2005
~
m(c+1) >165 GeV
121>0
~
m(c+1) >181 GeV
Giulia Manca, University of Liverpool
48
R Parity Violation Limits
EXP
(L=154 pb-1) :’211 1.1±0.4
EXP
(L=160 pb-1) :122 0.6±1.9
(L=238 pb-1) :121 0.5±0.4
(L=200 pb-1) :133 1.0±1.4
15th December 2005
All improve on Run I
OBS
2
tan,A0=0,<0
OBS
0(+) )>84(165) GeV/c2
2 M(c
1
0 M(c0(+)1)>95(181) GeV/c2
0 M(c0(+)1)>66(118) GeV/c2
Giulia Manca, University of Liverpool
49
Non-collider LSP searches
• DAMA, CDMS,
Edelweiss,..
Direct LSP
detection through
nuclear recoil
• Icecube: indirect
search for n from
LSP annhiliation
in the Sun
See talk from Bergstrom at SUSY05
15th December 2005
Giulia Manca, University of Liverpool
50
•
Chargino-Neutralino: Present
Lots of searches setting limits on c0(+) masses from
different sides
c0 c±1
Rp
M(c±1)>181
•
•
AMSB
M(c±1)>174 GMSB
M(c±1)>209
mSugra
M(c±1)>118
Getting close to the most favoured masses!
Still 1 fb-1 to analyse ! => Observe Susy or set better limits
 Hints from the Tevatron will help LHC to prioritise searches
15th December 2005
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51
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
15th December 2005
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,
Giulia Manca,
University of Liverpool-10
(g-2)
/2 = 19.0 ± 8.4x10
What about the future ?
53
•
•
•
•
SUSY at the LHC
Ecm of 14 TeV available!!
Between 1-2 fb-1 in the first
year of data taking!
In typical mSugra
scenario, squarks and
gluinos dominate =>
signatures with jets + MET
Very quick discovery !
What about
chargino and
neutralino ?
15th December 2005
(all plots from Ian Hinchliffe, SUSY
Giulia Manca, University of Liverpool
54
•
Chargino and Neutralino at the
LHC
Direct production cross-sections small
 But could be the only way to observe SUSY
•
~ ! (“focus point”)
if qg are ~
heavy
SUSY (pb) vs sparticle
mass(GeV/c2) for √s=14 TeV
In other regions trileptons signal
enhanced from squark-gluino cascade
15th December 2005
Giulia Manca, University of Liverpool
55
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
15th December 2005
Giulia Manca, University of Liverpool
56
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 !!
15th December 2005
Giulia Manca, University of Liverpool
57
15th December 2005
Back-up slides
Giulia Manca, University of Liverpool
58
Evidence for Cold Dark Matter existance
WMAP
J. Tonry et al
SN Ia CDM
D.N. Spergel et al., Astrophys.J.Suppl.148:213,2003
M
h2=0.12
U. Seljak & al astro-ph/0407372
SDSS (and
2dFGRS), 2005
15th December 2005
Giulia Manca, University of Liverpool
59
Cold Dark Matter from Bergstrom(SUSY05)
•
•
SUSY
•
•
Part of the “Concordance Model”, CDM  0.3  0.7
Gives excellent description of CMB, large scale
structure, Ly- forest, gravitational lensing, supernova
distances …
If consisting of particles, may be related to electroweak
mass scale: weak cross section, non-dissipative Weakly
Interacting Massive Particles (WIMPs). Potentially
detectable, directly or indirectly.
May or may not describe small-scale structure in
galaxies: Controversial issue, but alternatives (selfinteracting DM, warm DM, self-annihilating DM) seem
worse. Probably non-linear astrophysical feedback
processes are acting (bar formation, tidal effects,
mergers, supernova winds, …). This is a crucial problem
of great importance for dark matter detection rates.
15th December 2005
Giulia Manca, University of Liverpool
from Bergstrom(SUSY05)
60
Good particle physics candidates for Cold Dark
Matter:
Independent motivation from particle physics
• Axions (introduced to solve strong CP problem)
• Weakly Interacting Massive Particles (WIMPs,
3 GeV < mX < 50 TeV), thermal relics from Big
Bang: Supersymmetric neutralino
Axino, gravitino
Kaluza-Klein states
Heavy neutrino-like particles
Mirror particles
”Little Higgs”
plus hundreds more in literature…
• Non-thermal (maybe superheavy) relics:
wimpzillas, cryptons, …
15th December 2005
”The WIMP
miracle”: for
typical gauge
couplings and
masses of order
the electroweak
scale, wimph2 
0.1 (within factor
of 10 or so)
Giulia Manca, University of Liverpool
61
•
•
•
More on Dark Matter
From the WMAP results,
in mSugra there are only 4 regions allowed
Too much DM unless
 LSP light
 Annihilation enhanced
 Degeneracy or LSP content
But:
 If (g-2) is due to SUSY,
the sparticles masses are
small ~102 GeV
M1/
2
However, general MSSM model versions
give more freedom. At least 3 additional
parameters: , At, Ab (and perhaps
several more…)
In particular: special models like split
supersymmetry, models with CP
15th
December
2005
violation,
etc.
M0
Giulia Manca, University of Liverpool
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Current constrained regions
 Collider physics
Higgs mass < 114.1 GeV
 direct searches for
sparticles
 Higgs bound
 Astrophysics
 cold dark matter
a in [10;40]10-10
 Low energy
 a
 b into sg
15th December 2005
Giulia Manca, University of Liverpool
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Teavatron reach in M0-M12
15th December 2005
Giulia Manca, University of Liverpool
64 Indirect constraints on mSugra: Bs
•
•
SM rate heavily suppressed:


BR (B s    )  (3.5  0.9)  10
9
(Buchalla & Buras, Misiak & Urban)
SUSY rate may be enhanced:
S. Baek, Y.G.Kim, P. Ko, hep-ph/0406033
Complementary
to trilepton
searches
15th December 2005
Giulia Manca, University of Liverpool
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Impact of Bs Limits: Now
R. Dermisek, S. Raby, L. Roszkowski,
R. Ruiz de Austri, hep-ph/0507233
15th December 2005
S. Baek, Y.G.Kim, P. Ko, hep-ph/0406033
Giulia Manca, University of Liverpool
68
Impact of Bs Limits: L=8 fb-1
R. Dermisek, S. Raby, L. Roszkowski,
R. Ruiz de Austri, hep-ph/0507233
•
S. Baek, Y.G.Kim, P. Ko, hep-ph/0406033
Will severely constrain parameter space
 “Tevatron can rule out 29% of parameter space allowed by WMAP data within
mSUGRA.” B. Allanach, C. Lester, hep-ph/0507283
15th December 2005
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69
15th December 2005
JES Scale
Giulia Manca, University of Liverpool
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Chargino-Neutralino masses(mSugra)
M(c±) (GeV/c2)
Little dependence on
M0, high on M1/2
15th December 2005
M(c02)
(GeV/c2)
Giulia Manca, University of Liverpool
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Other masses
M(eR) (GeV/c2)
M(chargino)M(s
lepton)
 BR(leptons)
enhanced
15th December 2005
M(eR)-M(c±) (GeV/c2)
Giulia Manca, University of Liverpool
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Selection
Trileptons at D0
Main BG
Main Systematic
ee+l
Zgg,Wenu
JES,MC stat
e+l
QCD(38%) Wenu,WW,WZ
JES(3%),QCD,eff
+l
WZ,Wmunu
QCD,JES,reco
SUM
QCD(m),WZ(e)
JES,modelling of
qcd bg
15th December 2005
Giulia Manca, University of Liverpool
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Chargino Neutralino in gg+ET
In GMSB: 2 photons+ET
D0(CDF) Event selection:
-2 photons ET > 20(13) GeV
-ET>40(45) GeV
Limit
Main Syst
Main BG
D0
195 GeV
gID (8%)
QCD (70%)
CDF
167 GeV
gID (14%)
eg(50%)
CDF‡ and D0#
combined result:
m(c±)>209 GeV/c2
‡Phys.Rev.D.71,3 031104(2004)
#Phys. Rev. Letters 94,
041801(2005)
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Tau identification
- narrow cluster in central calorimeter
-search for matching high-Pt track
-define 2 cones 10o and 30o around the track
-let more tracks to enter in the inner cone
--discard event if there are tracks between the
2 cones
-reconstruct the cluster in the ShowerMax and
create a 0
-select events with mass(0 ,tracks) < M(tau)
-check E(cal) = sum(P)(tracks+ 0)
15th December 2005
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•
•
•
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
15th December 2005
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Mass measurements at the LHC
Ian Hinchliffe, SUSY05
15th December 2005
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…continue…
Ian Hinchliffe,
SUSY05)
15th December 2005
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15th December 2005
…continue
Ian Hinchliffe,
SUSY05)
Giulia Manca, University of Liverpool