Searches for Supersymmetry in the
CMS Experiment
Jeffrey D. Richman (UC Santa Barbara)
Representing the CMS Collaboration
21st International Conference on Supersymmetry and Unification of Fundamental Interactions
International Center for Theoretical Physics, Trieste, August 26–31, 2013
Outline
• Big themes and challenges for
SUSY searches
• Inclusive (generic) searches
• Naturalness-inspired searches:
t , b, g
• Search for EWKinos & sleptons
c , c ,
0
i
±
j
• SUSY decays with Higgs
• Multi-lepton & R-parity
violating signatures
• Conclusions
Drawing courtesy Sergio Cittolin
CMS PUBLIC SUSY RESULTS
https://twiki.cern.ch/twiki/bin/vie
w/CMSPublic/PhysicsResultsSU
S
New results in all of these areas.
Most use 19.5 fb-1 (√s =8 TeV).
2
CMS SUSY talks in the parallel sessions (I)
1. Search for SUSY in hadronic final states at CMS (Mon.)
Joshua THOMPSON
2. Search for SUSY in the single and di-lepton final state at CMS (Mon.)
Marco-Andrea BUCHMANN
3. Search for SUSY in multilepton final states at CMS (Mon.)
Andrea GOZZELINO
4. Search for SUSY in final states with photons at CMS (Tues.)
David MORSE
5. Interpretation of CMS SUSY results and outlook to 14 TeV data taking
(Tues.)
Frank GOLF
6. Dark matter searches in monojet and monophoton events at CMS
(Tues.)
Tai SAKUMA
3
CMS SUSY talks in the parallel sessions (II)
7. Search for direct stop and sbottom production at CMS (Thurs.)
Mariarosaria D’ALFONSO
8. Search for EWK production of gauginos and sleptons at CMS (Thurs.)
Ben HOOBERMAN
9. Interpretations of CMS SUSY searches in the context of R-parity
violation (Fri.)
My talk: just a small sampling of
Matthew WALKER
the many CMS SUSY results.
OTHER CMS PLENARY SESSION TALKS
Recent results on Higgs physics from CMS (Tues.)
Sridhara DASU
Recent results from exotic searches from CMS (Fri.)
Sunil SOMALWAR
4
CMS SUSY overview: a broad program
x = 0.25
x = 0.75
x = 0.20
x = 0.50
x = 0.50
1000
m(LSP)=0 GeV
1400
1200
Mass scales [GeV]
For decays with intermediate mass,
mintermediate = x×mmother-(1-x)×mlsp
CMS Preliminary
s = 8 TeV
s = 7 TeV
EWK Gaugino production
Slepton production
m(mother)-m(LSP)=200 GeV
x = 0.25
x = 0.50
x = 0.75
x = 0.05
x = 0.50
left-handed top
unpolarized top
right-handed top
x = 0.50
x = 0.75
x = 0.95
x = 0.50
x = 0.95
800
Sbottom production
SUS-13-012 SUS-12-028 L=19.5 11.7 /fb
SUS-12-005 SUS-11-024 L=4.7 /fb
SUS-13-004 SUS-12-024 SUS-12-028 L=19.3 19.4 /fb
x = 0.25
x = 0.05
600
Stop production
Summary of CMS SUSY Results* in SMS framework SUSY 2013
5
Mass scale (GeV)
SUS-13-004 SUS-13-007 SUS-13-008 SUS-13-013 L=19.4 19.5 /fb
SUS-11-011 L=4.98 /fb
SUS-12-004 L=4.98 /fb
SUS-12-010 L=4.98 /fb
SUS-13-008 SUS-13-013 L=19.5 /fb
400
Squark production
0
g~ ® qq c~
0
g~ ® qq c~
0
g~ ® bb c~
0
g~ ® tt c~
0 +- 0
g~ ® qq (c~ ® l l c~ )
0 2 0 0
g~ ® qq(c~ ® t t c~ |c~ )
2
0 0
g~ ® qq(c~±® Wc~ |c~ )
~ 0
g~ ® t(t ® tc~ )
0
g~ ® qq(c~± ® l±n c~ )
0
SUS-11-010 L=4.98 /fb
SUS-11-021 SUS-12-002 L=4.98 4.73 /fb
SUS-13-013 L=19.5 /fb
SUS-12-001 L=4.93 /fb
SUS-12-001 L=4.93 /fb
SUS-13-008 SUS-13-013 L=19.5 /fb
0
SUS-11-024 SUS-12-005 L=4.7 /fb
SUS-13-011 L=19.5 /fb
SUS-11-030 L=4.98 /fb
SUS-13-014 L=19.5 /fb
SUS-13-006 L=19.5 /fb
SUS-13-006 L=19.5 /fb
SUS-13-011 SUS-13-004 L=19.5 19.3 /fb
~ ~0
t®tc
~ ~0
t®tc
~ ~+ ~0
t ® b(c ® W c )
~ ~± ~0
t ® b (c ® W c )
~ ~0 ~ 0
t ® t b c ( c ® H G)
SUS-12-028 L=11.7 /fb
SUS-13-008 SUS-13-013 L=19.5 /fb
SUS-13-008 L=19.5 /fb
0 0
0 0
SUS-13-006 L=19.5 /fb
SUS-13-017 L=19.5 /fb
SUS-13-006 L=19.5 /fb
SUS-13-006 L=19.5 /fb
2
c~ c~ ® W Z c~ c~
0 0
± 20
c~ c~ ® H W c~ c~
0 0
0 2
±
c~ c~ ® l t n c~ c~
0 0
02 ±
c~ c~ ® ttt n c~ c~
SUS-13-006 L=19.5 /fb
*Observed limits, theory uncertainties not included
Only a selection of available mass limits
Probe *up to* the quoted mass limit
200
~ ~0
l ® lc
± 0
c~ c~ ® l l n c~ c~
+2 - + - 0 0
c~ c~ ® l l n n c~ c~
0 ±
~ 0
b ® b c~
~
0
b ® tW c~
~
0
b ® bZ c~
0
g~ ® qq (c~ ® Z c~ )
2
0
g~ ® qq(c~±® W c~ )
0
0 0
±
g~ ® qq(c~ ®g c~ |c~ ® W c~ )
2
0
0
g~ ® qq(c~ ® g c~ )
~ ±2 0
g~ ® b(b ® t(c~ ® Wc~ ))
SUS-13-012 SUS-12-028 L=19.5 11.7 /fb
SUS-12-005 SUS-11-024 L=4.7 /fb
0
Gluino production
q~ ® q c~
0
q~ ® q c~
gluino production
squark
stop
sbottom
EWK gauginos
slepton
10
~~
tt*
q= u,d,s,c L,R
LPCC SUSY s WG
+ c~ c~
Stop pair
production
Electroweak
production
± 0 ~~
c~ c~ qq*
Strong production
1
10-1
10-2
~+~-
10-3 l l
g~~g
105
103
102
10
LHC SUSY Cross Section Working Group
104
10-4
200
400
600
800
1000
1200
1400
1600
arXiv:1206.2892
SUSY sparticle mass [GeV]
https://twiki.cern.ch/twiki/bin/view/LHCPhysics/SUSYCrossSections
NLO(-NLL)
s(pp® and
SUSY)
[pb]
Big themes: production
decays
#events in 20 fb-1 8TeV LHC data
https://twiki.cern.ch/twiki/bin/view/LHCPhysics/SUSYCrossSections
6
10
~~
tt*
q= u,d,s,c L,R
LPCC SUSY s WG
+ c~ c~
Stop pair
production
Electroweak
production
± 0 ~~
c~ c~ qq*
Strong production
1
10-1
10-2
~+~-
10-3 l l
g~~g
Exploring 𝜎 = ~1 fb  ~1 pb
105
103
102
10
LHC SUSY Cross Section Working Group
104
10-4
200
400
600
800
1000
1200
1400
1600
arXiv:1206.2892
SUSY sparticle mass [GeV]
https://twiki.cern.ch/twiki/bin/view/LHCPhysics/SUSYCrossSections
NLO(-NLL)
s(pp® and
SUSY)
[pb]
Big themes: production
decays
#events in 20 fb-1 8TeV LHC data
https://twiki.cern.ch/twiki/bin/view/LHCPhysics/SUSYCrossSections
7
Big themes: background measurement
5
July 2013
³1j
W
³2j
³3j
³4j
jet
³1j
³3j
Z
³2j
ET > 30 GeV
jet
| h | < 2.4
36, 19 pb-1
³4j
g
Zg
ET > 15 GeV
Wg
Diboson processes
DR(g ,l) > 0.7
7 TeV CMS measurement
8 TeV CMS measurement
7 TeV Theory prediction
CMS
WVg
19.3 fb-1
8 TeV Theory prediction
WZ
4.9 fb-1 4.9 fb-1
3.5 fb-1 19.6 fb-1
ZZ
CMS 95%CL limit
WW+WZ WW
5.0 fb-1
EPJC C13 2283 (2013) (WV)
EWK-11-009
SMP-013-009
SMP-12-006 (WZ), 12-005 (WW7), 13-005(ZZ8)
JHEP 1301 063 (2013) (ZZ7), PLB 721 190 (2013) (WW8)
5.0 fb-1
SUSY down here somewhere?
10
104
3
10
102
10
1
10-1
JHEP 10 132 (2011)
JHEP 01 010 (2012)
SMP-12-011 (W/Z 8 TeV)
(W,Z) + jets
[pb]
stot
Production Cross Section,
8
Big themes: background measurement
5
10
July 2013
W
³4j
104
3
10
102
10
1
³1j
³2j
³1j
Z
³2j
³3j
³4j
Wg
Zg
ET > 15 GeV
g
ET > 30 GeV
DR(g ,l) > 0.7
7 TeV CMS measurement
8 TeV CMS measurement
7 TeV Theory prediction
8 TeV Theory prediction
CMS 95%CL limit
WW+WZ WW
WZ
ZZ
CMS
WVg
19.3 fb-1
5.0 fb-1
4.9 fb-1 4.9 fb-1
3.5 fb-1 19.6 fb-1
36, 19 pb-1
5.0 fb-1
JHEP 10 132 (2011)
JHEP 01 010 (2012)
SMP-12-011 (W/Z 8 TeV)
EPJC C13 2283 (2013) (WV)
EWK-11-009
SMP-013-009
SMP-12-006 (WZ), 12-005 (WW7), 13-005(ZZ8)
JHEP 1301 063 (2013) (ZZ7), PLB 721 190 (2013) (WW8)
jet
| h | < 2.4
jet
³3j
Inclusive cross sections are
well measured, but details of
kinematic distributions are
key for SUSY searches.
10-1
SUSY down here somewhere?
[pb]
stot
Production Cross Section,
9
Big themes:
key SUSY background
• Heaviest SM particle s (pp ® tt ) = (227 ± 3±11±10) pb at 8 TeV
• Jets, b-jets, leptons, missing transverse momentum (MET)
• Now have many detailed studies of kinematic
distributions.
•
CMS TOP-11-020
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsTOPSummaryPlots
CMS
TOP-12-027
Electron
helicity angle
W polarization
top pT spectrum
https://twiki.cern.ch/twiki/bin/view/CMSPublic/Phy
sicsResultsTOP12027
http://arxiv.org/abs/1308.3879
s = 8 TeV, ò Ldt = 19.5 fb -1
CMS
2
1.5
1
0.5
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS13011
0
Data/MC
Big themes: tails of SM kinematic distributions
Entries / 30 GeV
• SUSY processes usually do not
10
have narrow features in
SUS-13-011
10 Direct tt
observed distributions.
• Search is performed in the
10
extreme tails of SM processes.
10
Narrow kinematic region of
10
phase space; possible rare
100 150 200 250 300
50
0
detector effects also.
M [GeV]
• As far as possible, use data-driven methods based on
control samples  use multiple, complementary
approaches. MC/theory plays key role in validating our
understanding of these control samples.
• Multiple methods: critical for discovery scenarios!
11
5
~
0
c BDT1 Loose
t ® t~
1
4
Data
1 l top
tt® ll
W+jets
rare
0
~
c (250/50)
SM + t ® t~
3
1
2
T
The pentaquark phenomenon, 2002-2005
Slide courtesy of R. Schumacher
Photoproduction on Deuteron Q+
From Particles and Nuclei International Conference, Santa Fe, 2005
CLAS-d1
LEPS-C
CLAS g11
SAPHIR
Photoproduction on Proton pKs0
Photoproduction on Proton nK+K-p+
CLAS-p
DIANA
Exclusive K + (N) → pKs0
SPHINX
JINR
SVD2
p + A → pKs + X
0
p + p → pKs0 + S+
Pentaquark
observations
BES J,Y
CDF
Inclusive
→
SVD2
NA49/CERN
+X
D(*) -
FOCUS
HERA-B
ALEPH
WA89
ZEUS
H1/HERA
p
Pentaquark
non-observations
9
11
1
3
12
2002
2
4
E690
STAR/RHIC
ZEUS
10
WA89
ALEPH, Z
Inclusive Q + + → p K+
Q0c
HyperCP
COSY-TOF HERA-B
Other Q+ Upper Limits
--
BELLE
BaBar
ZEUS nBC
Hermes
Inclusive lepton + D, A → p Ks0
p + p (or A) → X
CLAS-d2
LEPS-d2
LEPS-d
ZEUS
ALEPH FOCUS
5
6
7
8
2003
9
10
11
12
1
2
3
4
5
6
7
8
2004
9
10
11
12
1
2
3
4
5
6
7
8
9
10
11
12
2005
Let’s not do this! (I don’t think we will.)
12
Big themes: many (& complex) signatures
gluino
SUSY LM6
benchmark
Higgs
sector
squarks
Direct
production
via strong
processes
gauginos/higginos
sleptons
neutralino
(LSP)
Direct
production
via electroweak
processes
13
SUSY cascade starting from gluino decay
SUSY LM6
benchmark
neutralino
(LSP)
14
Decays of ~t1  neutralinos, charginos
SUSY LM6
benchmark
neutralino
(LSP)
15
Decays ofc 20c 20 : here come the leptons!
SUSY LM6
benchmark
c
0
2
neutralino
(LSP)
16
Decays of
: more leptons!
SUSY LM6
benchmark
Even more possibilities
...and in GMSB,
the lightest
neutralino can
decay into a
gravitino  MET
neutralino
(LSP)
... and in R-parity
violating SUSY, the
neutralino can
decay into SM
particles no MET
17
Decays of
: more leptons!
SUSY LM6
benchmark
pp ® c1± c 20
® W ± c10 + H c10
H
neutralino
(LSP)
New program of
searches for SUSY
decays with Higgs.
pp ® c + c
±
1
0
2
® W ± c10 + H c10
18
Frank Golf
parallel talk
Big themes: Interpretation(s)
• Early LHC running: heavy use of cMSSM to connect with
results from Tevatron. (Not sufficiently general.)
• Today: Extensive use of simplified models. Reasonably well
suited to natural SUSY spectra. Big assumption: BF=100%.
• Alternatives: pMSSM and efficiency models.
SMS: gg, g ® qq c1
SUS-13-012 (Jets+MHT)
m
(GeV)
0
1
0
Efficiency
1
0.8
CMS Simulation s = 8 TeV
ET > 30
ET > 50
ET > 120
1400
10
1
10-1
-3
10-2
10
s PMSSM
0.6
Excluded
0.4
Not
excluded
0.2
1200
m(g)
95% C.L. upper limit on cross section (pb)
https://twiki.cern.ch/twiki/bin/view/CMSP
ublic/PhysicsResultsSUS13012
Prior
0
0 20 40 60 80 100 120 140 160 180 200 220
gen
ET (GeV)
1
1000
m~g (GeV)
CMS Preliminary, 19.5 fb-1, s = 8 TeV
800
0
pp ® ~g ~g, ~g ® q q ~c NLO+NLL exclusion
Observed ± 1 stheory
Expected ± 1 sexperiment
600
Expected limit
w/experimental
uncertainty
Observed limit
w/theoretical
uncertainty
Efficiency model for
SUS-13-013 ( ± ± )
1200
1000
800
600
400
400
200
m( c )
LSP
pMSSM interpretation of
SUS-13-012
ETmiss(gen)
https://twiki.cern.ch/twiki/bin/view/CMS
Public/PhysicsResultsSUS13013
19
Outline
• Big themes and challenges for
SUSY searches
• Inclusive (generic) searches
• Naturalness-inspired searches:
g, t , b
• Search for EWKinos & sleptons
c , c ,
0
i
±
j
• SUSY decays with Higgs
• Multi-lepton & R-parity
violating signatures
• Conclusions
Drawing courtesy Sergio Cittolin
CMS PUBLIC SUSY RESULTS
https://twiki.cern.ch/twiki/bin/vie
w/CMSPublic/PhysicsResultsSU
S
New results in all of these areas.
Analyses use 19.5 fb-1 (√s =8 TeV).
20
Generic searches for jets + MET
1 Jet + MET
Dark matter search
EWK production + ISR
ISR jet or
photon
c
0
1
miss
T
2 Jets + MET
Multi. Jets + MET
Strong production
Strong production
e.g., pp ® qq e.g., pp ® gg
p
c
SM: Z(νν) + 1 jet
0
1
SM: QCD dijets
SM: many sources!
+ fake MET from Both real & fake
mismeasuremento MET.
f jets; W + jets,...
For dark matter results, see Sunil Somalwar plenary & Tai Sakuma parallel talk.
21
All-hadronic SUSY search using 𝛼T
SUS-12-028
http://arxiv.org/abs/1303.2985
aT º ETJ / M T (J1 J2 ) =
2
Randall and Tucker-Smith
http://arxiv.org/pdf/0806.1049
0
J2
T
J1
2(1 - cos Dj J1 J2 )
SUSY qq ® (qc1 )(q c1 )  dijets +
MET
J
J2
QCD
J1
T
E /E
aT »
2
J. Thompson
& F. Golf
parallel talks
ETJ2 / ETJ1
2
1
£
2
J1
0
ETJ2 / ETJ1
aT »
Dj J1 J2
Generalized to multijet events in CMS (form 2 pseudo-jets).
Events / 0.05
108
107
106
105
104
103
102
10
1
0
0.5
2 ≤ Njets ≤ 3
1
m( c10 )
1.5
QCD multjet
Data
Standard model
Non-multijet
Multijet
Reference model D2
2.5
CMS, Lint = 11.7 fb-1, s = 8 TeV
2 £ njet £ 3
2
pp ® bb, b ® bc10
3
aT
aT
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS12017
8 degeneratemass squarks
1 squark (but
~b search more
sensitive!)
m(q)
22
Generic hadronic SUSY search using MHT
SUS-13-012
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS13012
J. Thompson parallel talk
• Signature: Jets + MHT; events with leptons are vetoed
– Jets: ≥3 jets with pT > 50 GeV, no b-tagging.
– Veto event if MHT vector is ≈aligned with any of 3 leading jets.
• Bin data in
HT =
å
pTj
j= jets
– HT
– missing HT (MHT)
HT = HT = pTj
j= jets
– Jet multiplicity (3—5, 6—7, ≥8 jets)
å
• Background estimation: largely data driven.
• ttbar with Wl 𝜈
• W  l 𝜈 + jets
• ttbar with W𝜏 (h) 𝜈
• W  𝜏 (h) 𝜈 + jets
Control sample: Singlelepton + jets + MHT
• Z𝜈𝜈 + jets
• QCD multijet events
MHT ~ aligned with high pT jet.
Control samples:
𝛾 + jets,
Z(𝜇𝜇)+jets
Control sample:
Multijets with re-balance and
smear procedure
23
Distribution in bins of N(jets), HT , and HT
CMS PAS SUS-13-012
HT : 0.8-1.0 TeV
HT : 1.0-1.2 TeV
24
Statistical interlude
• Consider the bin with
– N(observed) = 9 events
– N(background) = 0.8 ± 1.7 events
See CMS PAS SUS-13-012,
Table 1, p. 10
Njets: 6-7
HT: 500-800 GeV
MHT>450 GeV
• First, let’s ignore the uncertainty on the background. What
is the probability for a Poisson with μ=0.8 to fluctuate to at
least 9 events?
– Prob( n≥9 | μ =0.8 ) = 1.8 × 10-7
Have we discovered new physics?
• NO! The uncertainty is crucial!
– Prob( n≥9 | μ = 0.8 ± 1.7) ≈ 0.15
• This example highlights the importance of quantifying the
uncertainties on the SM backgrounds.
25
Search for generic jets and MET: results
• Simplified model exclusion plots
CMS PAS SUS-13-012
1. Compute excluded cross section for each model in param space
2. Compare to reference cross section to see if model excluded
• Assume 100% branching fraction for stated process!
mLSP (GeV)
600
500
400
300
200
L
0
R
(L + R)
1
~ ~
~
q +~
q (~u,d,~
s,c)
Squark pair
production;
see F. Golf talk
CMS Preliminary, 19.5 fb-1, s = 8 TeV
pp ® ~q ~q, ~
q ® q ~c NLO+NLL exclusion
Observed ± 1 stheory
Expected ± 1 sexperiment
one light ~q
1400
m~q (GeV)
1200
10
1
10-1
10-2
10-3
10
1
10-1
-3
10-2
10
95% C.L. upper limit on crossAs
section
(pb) weak
before,
100
0
1
Signal efficiency
increases away
from diagonal
 excluded 𝜎 falls
1000
m~g (GeV)
CMS Preliminary, 19.5 fb-1, s = 8 TeV
800
pp ® ~g ~g, ~g ® q q ~c NLO+NLL exclusion
Observed ± 1 stheory
Expected ± 1 sexperiment
600
Gluino pair
production
300 400 500 600 700 800 900 1000
1200
800
600
400
200
400
1000
mLSP (GeV)
upper limit
on cross
section (pb)26
limit 95%
with C.L.
reduced
number
of squarks!
Search for generic jets and MET: results
• Simplified model exclusion plots
CMS PAS SUS-13-012
1. Compute excluded cross section for each model in param space
2. Compare to reference cross section to see if model excluded
• Assume 100% branching fraction for stated process!
mLSP (GeV)
CMS Preliminary, 19.5 fb-1, s = 8 TeV
0
1
R
1400
pp ® ~q ~q, ~
q ® q ~c NLO+NLL exclusion
Observed ± 1 stheory
Expected ± 1 sexperiment
L
~ ~
~
q +~
q (~u,d,~
s,c)
Squark pair
production
(L + R)
600
500
400
300
one light ~q
m~q (GeV)
1200
10
1
10-1
10-2
10-3
10
1
10-1
-3
10-2
10
95% C.L. upper limit on crossAs
section
(pb) weak
before,
200
0
1
1000
Observed limit
w/theoretical
Th’y cross section fall-off
uncertainty
100
800
m~g (GeV)
CMS Preliminary, 19.5 fb-1, s = 8 TeV
pp ® ~g ~g, ~g ® q q ~c NLO+NLL exclusion
Observed ± 1 stheory
Expected ± 1 sexperiment
600
Gluino pair production
Expected limit
w/experimental
uncertainty
300 400 500 600 700 800 900 1000
1200
800
600
400
200
400
1000
mLSP (GeV)
upper limit
on cross
section (pb)27
limit 95%
with C.L.
reduced
number
of squarks!
Outline
• Big themes and challenges for
SUSY searches
• Inclusive (generic) searches
• Naturalness-inspired searches:
t , b, g
• Search for EWKinos & sleptons
c , c ,
0
i
±
j
• SUSY decays with Higgs
• Multi-lepton and R-parity
violating signatures
• Conclusions
Drawing courtesy Sergio Cittolin
CMS PUBLIC SUSY RESULTS
https://twiki.cern.ch/twiki/bin/vie
w/CMSPublic/PhysicsResultsSU
S
New results in all of these areas.
Analyses use 19.5 fb-1 (√s =8 TeV). 28
The focus on natural SUSY signatures
• With the discovery of the/a
Higgs boson, the problem of the
stability of m(H) against
radiative corrections has
become urgent.
• Many searches designed for
signatures motivated by a
“natural SUSY” solution to the
gauge hierarchy problem.
N. Arkani-Hamed,
http://indico.cern.ch/getFile.py/access?contribId=7
&sessionId=2&resId=0&materialId=slides&confId=
157244
M. Papucci, J.T. Ruderman, and A. Weiler,
Natural SUSY Endures,
http://arxiv.org/abs/1110.6926
29
Search for direct stop production:
SUS-13-011
Parallel talks: Mariarosaria D’Alfonso, Frank Golf
pp ® t1t1
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS13011 http://arxiv.org/abs/1308.1586
4-body
m(t1 ) < m( c10 )
t ® bW * c10
violates assumed
spectrum
(off-shell W)
3-body
2-body
m(t ) ³ m(t) + m( c10 )
t ® bc1+ ® bW +(*) c10
has extra mass parameter
+m(b)
30
Search for direct stop production:
SUS-13-011
Parallel talks: Mariarosaria D’Alfonso, Frank Golf
pp ® t1t1
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS13011 http://arxiv.org/abs/1308.1586
4-body
m(t1 ) < m( c10 )
t ® bW * c10
violates assumed
spectrum
(off-shell W)
3-body
2-body
m(t ) ³ m(t) + m( c10 )
t ® bc1+ ® bW (*) c10
has extra mass parameter
+m(b)
31
Search for direct stop production:
SUS-13-011
Parallel talk: Mariarosaria D’Alfonso
pp ® t1t1
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS13011 http://arxiv.org/abs/1308.1586
t ® bW * c10
m(t1 ) < m( c10 )
violates
assumed
Same
final
spectrum
(off-shell
W)
state
but different
kinematics!
m(t ) ³ m(t) + m( c10 )
t ® bc1+ ® bW (*) c10
+m(b)
32
Search for direct stop production:
SUS-13-011
Parallel talk: Mariarosaria D’Alfonso
pp ® t1t1
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS13011 http://arxiv.org/abs/1308.1586
MT > 120 GeV
MET > 100 GeV
t ® t c10 (´100)
t ® bW * c10
(off-shell W)
m(t ) ³ m(t) + m( c10 )
Use BDTs
for separate
modes &
regions.
MT > 120 GeV
MET > 100 GeV
t ® bc1+ (´100)
+m(b)
33
Search for direct stop: initial state radiation
SUS-13-011
• The effects of initial-state radiation are important for the
signal efficiency in the region where MET is small.
• Does the simulation get this right (MADGRAPH) ?
• Study in Z+jets and ttbar.
Z + jets
pT(jets)
ttbar(l+l-) + jets
34
Search for direct stop: initial state radiation
SUS-13-011
• The effects of initial-state radiation are important for the
signal efficiency in the region where MET is small.
• Does the simulation get this right (MADGRAPH) ?
MC predicts up to 20% too
• Study in Z+jets and ttbar.
much ISR at high pT
DATA/MC
Z + jets
pT(jets)
ttbar(l+l-) + jets
35
Search for
SUS-13-011
SUS-13-004
m( c10 )
pp ® t1t1 : results
For each
decay
channel,
100% BF
is assumed!
1-lepton
analysis
~tt ~X10
1-lepton
analysis
~tb~X1+
Razor analysis
0 lep + 1 lep
m(t )
36
Search for direct stop: dependence on BF
300
400
500
Observed limits
[GeV]
700
1
~
0
BF(t ® t~c ) = 1.0
1
~
0
BF(t ® t~c ) = 0.9
1
~
0
BF(t ® t~c ) = 0.8
1
~
0
BF(t ® t~c ) = 0.7
1
~
0
BF(t ® t~c ) = 0.6
1
~
0
BF(t ® t~c ) = 0.5
600
m~
t
37
800
s = 8 TeV, ò Ldt = 19.5 fb-1
t
CMS
400 pp ® ~t ~t*, ~t ® t c~0
1
BDT analysis
200
1
350 unpolarized top
300
250
200
150
100
=m
c~ 0
W
t
1
100
50
0
t
-m
=m
c~ 0
-m
m~
1
m~
mc~0 [GeV]
Search for b-jets, same-sign dileptons, MET
SUS-13-013
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS13013
Parallel talk: Marco-Andrea Buchmann
p
-
-
W
-
W
b
t
t
b
+
p
SM same-sign
dilepton
background
Events / 10 GeV
100
80
60
CMS Preliminary
Leading
lepton pT
40
20
s = 8 TeV, Lint = 19.5 fb-1
T
High-p leptons
Data
Rare SM processes
Charge misID
Non-prompt e/ m
Total bkg uncertainty
0
0 20 40 60 80 100 120 140 160 180 200
T
pleading [GeV]
• 54 signal bins!
• N(b) = 0, 1, 2; N(J) =2-3, ≥4,
MET bins (50-120,>120 GeV),
HT bins (200-400, >400 GeV).
• Sensitivity to direct sbottom,
gluino pairs, RPV SUSY, samesign top, etc.
SM background
38
Same-sign dileptons: search for pp ® b1b1
c ®W
400
350
300
250
200
150
100
50
CMS Preliminary, 19.5 fb-1, s = 8 TeV
1
~ ~ ~
0
pp®b1b*1, b1® tW~c NLO+NLL exclusion
1
1
Observed ± 1 stheory
Expected ± 1 sexperiment mc~0/mc~+ = 0.8
msbottom (GeV)
CMS Preliminary, 19.5 fb-1, s = 8 TeV
1
~~ ~
0
pp®b1b1*, b1® tW~c NLO+NLL exclusion
1
1
Observed ± 1 stheory
Expected ± 1 sexperiment mc~0/mc~+ = 0.5
10
3
102
10
39
m(b1 )
3
10
102
10
m(b1 )
300 350 400 450 500 550 600 650
400
350
300
250
200
150
350 400 450 500 550 600 650
msbottom (GeV)
CMS Preliminary, 19.5 fb-1, s = 8 TeV
1
Observed ± 1 stheory
Expected ± 1 sexperiment
~~ ~
0
pp®b1b1*, b1® tW~c NLO+NLL exclusion
1
mc~0 = 50 GeV
350 400 450 500 550 600 650
msbottom (GeV)
95% C.L. upper limit on cross section (fb)
0
20
40
60
80
100
120
m(b1 )
100
50
600
550
500
450
400
350
300
250
200
150
High pT lepton
selection
95% C.L. upper limit on cross section (fb)
95% C.L. upper limit on cross section (fb)
Low pT lepton
selection
High pT lepton
selection
mLSP (GeV)
m( c10 )
mLSP (GeV)
mchargino (GeV)
0
1
1
m( c10 )
m( c1+ )
m( c )
c
m( c )
b1 ® t c1-
+
1
0
1
Test how the exclusion region
depends on m( c1+ ) - m( c10 )
m(b1 )
SUS-13-013
m( c10 ) = 50 GeV m( c10 ) / m( c1+ ) = 0.5 m( c10 ) / m( c1+ ) = 0.8
Examples for pp ® gg , g ® bb c10 , g ® tt c10
b-Jets + MET
(all hadronic search)
b-Jets + 1 lepton +
MET
b-Jets + 2 same-sign
leptons + MET
Require ≥3 b jets, no
Require 1 lepton, large Classic SUSY signature.
isol leptons, large MET. MET, large N(jets), b
Key issue is “fake”
jets.
leptons.
Off-shell ~t, but also have on-shell interpretation.
• For many SUSY searches, ttbar is the dominant background.
• Lots of real MET from W decays
• b-tagging suppresses Z + jets, W + jets.
40
SUSY search for b-jets, 1 lepton, and MET
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS13007
CMS PAS SUS-13-007
Parallel talk: Marco-Andrea Buchmann
Lepton spectrum method: for leptons produced in W decay,
the lepton spectrum can be used to measure the 𝜈 spectrum.
Events/50 GeV
CMS Preliminary
s = 8 TeV
-1
19.4 fb
Makes use of W helicity fractions in tbW
Data
Sum predicted
2
Single Tau
10
Dilepton
(m~ ,m
g
)=(1100 GeV,100 GeV)
LSP
HT>500 GeV
Njet ³ 6, Nb³ 2
10
1
...and W helicity fractions in W+jets
Normalized
residuals
10-1
3
2
1
0
-1
-2
-3
200 300 400 500 600 700 800 900 1000
ET [GeV]
200 300 400
500 600
700 800 900 1000
ET [GeV]
41
SUSY search for b-jets, 1 lepton, and MET
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS13007
Parallel talk: Marco-Andrea Buchmann
CMS PAS SUS-13-007
Δ𝜑(lepton, W) method: strong suppression of 1-lepton
background (similar to MT). Also use ST = pT(lep) + MET.
700
600
500
CMS Preliminary
b
Single-lepton
N search
lep
ST ,
Njet ³6, Nb³2
HT>500 GeV
Df >1
~
pp ® ~
g~
g, ~
g ® tt c
0
s = 8 TeV
NLO-NLL exclusions
Observed ± 1 stheory
g
LSP
19.4 fb-1
=600)
10-1
10-2
10-3
s = 8 TeV
Muons
HT >500 GeV
lep
350<ST <450 GeV
L = 19.4 fb
m(~
g) [GeV]
-1
1.5
LSP
=0)
2
2.5 3
Df(m,W)
95% C.L. upper limit on s [pb]
42
Optimized for gluino pair production: N(J)≥6 and N(b)≥2.
400
300
200
100
Expected ± 1 s experiment
1
SMS(M~=1250,M
SMS(M~=1150,M =300)
LSP
g
Z
SMS(M~=1000,M
tt®2l
W
tt®1l
CMS Simulation
0.5
g
0
600 700 800 900 1000 1100 1200 1300 1400
103
102
10
1
10-1
10-20
Signal region
0
m(~
c ) [GeV]
Events
Search for b-jets & MET: pp ® gg, g ® bb c10
m~c (GeV)
J. Thompson parallel
talk
0
http://arxiv.org/abs/1305.2390
800
600
1000
CMS, s = 8 TeV
800
1
0
pp ® ~g ~g, ~g ® b b ~c
600
m( c )
0
1
400
0
400
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS12024
1000
1
200
SUS-12-024
1200
1400
m~g (GeV)
Acceptance x
Efficiency
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
m(g)
A´ Î
m~c0 (GeV)
1200
800
600
400
200
800
1
1000
1200
Excluded
cross section
CMS , L = 19.4 fb-1, s = 8 TeV
Observed ± 1 stheory
Expected ± 1 sexperiment
600
1400
m~g (GeV)
0
pp ® ~g~g, ~g ® b b ~c NLO+NLL exclusion
0
400
m( c )
0
1
1000
1
m(g)
1
10-1
10-2
-3
10
95% CL upper limit on cross section (pb)
43
Search for b-jets and MET with razor variables
SUS-13-004
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS13004
• “Razor” kinematic variables
C. Rogan, arXiv:1006.2727
• Variables defined in terms of a dijet topology. For
higher multiplicity, cluster jets into 2 pseudojets.
SM Background
Signal has
tail at
high R2
mgluino = 1325 GeV
mLSP=50 GeV
44
Searches for gluino pair production (b-jets)
4b + MET final state:
hadronic searches most sensitive.
m( c )
0
1
4t + MET final state:
single lepton search most sensitive.
m( c )
0
1
Razor
𝛼T
b-jets
+MET
3-lepton+b
2 SS1-lepton
lepton+b
Razor +b
0-lepton
+b
m(g)
No exclusion for M(LSP) ≳ 750
GeV.
m(g)
No exclusion for M(LSP) ≳ 600
GeV.
45
Outline
• Big themes and challenges for
SUSY searches
• Inclusive (generic) searches
• Naturalness-inspired searches:
t , b, g
• Search for EWKinos & sleptons
c , c ,
0
i
±
j
• SUSY decays with Higgs
• Multi-lepton and R-parity
violating signatures
• Conclusions
Drawing courtesy Sergio Cittolin
CMS PUBLIC SUSY RESULTS
https://twiki.cern.ch/twiki/bin/vie
w/CMSPublic/PhysicsResultsSU
S
New results in all of these areas.
Analyses use 19.5 fb-1 (√s =8 TeV).
46
Electroweak production: c , c , and
±
j
0
i
SUS-13-006
±
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS13006
Parallel talk: Ben Hooberman
c c ® 3 + n + 2c
c1± c 20 ® WZ + 2 c10
3 lep & SS dileptons
3 lepton & Z + dijet
±
1
0
2
0
1
+ -
c i0 c 0j ® ZZ + 2G
3 lep, 4 lep, Z dijet
®
+ -
+ 2 c10
Opposite-sign dileptons (off Z)
47
Results: Electroweak production of c , c
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS13006
1
c10 c10 ® (ZG)(ZG)
800
700
600
500
400
300
200
100
CMS Preliminary
>
±
m~c 1
0
m ~c 1
1 1
observed CLS limits (95% CL)
0 ± ~
pp ® ~c ~c , ( l , BF(l+l )=0.5)
2 1 L
0 ± ~
pp ® ~c ~c , ( lR, BF(l+l )=1)
2 1
~
0 ±
pp ® ~c ~c , ( no l, BF(WZ)=1)
2 1
~
0 ±
pp ® ~c ~c , ( no l, BF(WH)=1)
2 1
+ - ~
pp ® ~c ~c , ( lL, BF(l+l )=1)
=
0
m ~c 2
s = 8 TeV, Lint = 19.5 fb-1
CMS Preliminary s = 8 TeV, L = 19.5 fb-1
1
observed 4l + 3l
sNLO ± 1 s
150 200 250 300 350 400
GMSB ZZ+ETmiss
tanb = 2
M1 = M2 = 1 TeV
c
95% C.L. CLs cLimits
1
2
observed 2l 2j + 4l + 3l
expected median ± 1 s
observed 2l 2j
m~± = m~0 [GeV]
int
10010 200 300 400 500 600
700 800
1
m~l = 0.5mc~± + 0.5mc~0
1
10-1
𝜇 < 330 GeV
excluded
at 95% CL
m~
[GeV]
0
c
95% CL upper limit on s [pb]
combine
Chargino-Neutralino
production/decay
scenarios
GMSB Z-enriched
higgsino scenario
48
m( c10 ) » m( c 20 ) » m( c1± ) » m
Parallel talk: Ben Hooberman
SUS-13-006
±
j
0
i
EWK production of c ± , c 0: Higgs final states
SUS-13-017
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS13017
Parallel talk: Ben Hooberman
Natural SUSY models suggest higgsinos are light.
Search for WH +MET in three channels (1 lepton, SS dilepton, multilepton)
pp ® c c
±
1
0
2
® W ± c10 + H c10
Single lepton analysis
SS lepton analysis
Multilepton analysis
49
EWK production of c ± , c 0: Higgs final states
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS13017
SUS-13-017
Parallel talk: Ben Hooberman
1-lepton channel
W(l nu) + H(bb) + MET
Same-sign dileptons
W(l n) + H(WW) + MET
Multilepton channels
W(l nu) + H(WW, ZZ, 𝜏𝜏)+MET
1 lepton, exactly 2 jets,
both b jets, kinematic
cuts, MET, SIGNAL: m(bb)
2 same-sign leptons, 2-3 Mainly: 3 leptons, low HT, and
jets, no b-jets, kin. cuts, no b-tagged jets.
SIGNAL m(l, J1, J2) <120
1 lep, MET > 150 GeV
Events / 50 GeV
12
10
8
6
4
2
00
CMS Preliminary
> 150 GeV
s = 8 TeV, ò Ldt = 19.5 fb -1
miss
ET
theory
observed limit
Data
2l top
1l top
WZ ® ln bb
W+bb
1
0
1
0
M (bb )
W+light jets
1 2
± 0
Rare
2 lepton
ttbar
Total Uncertainty
~0) (200/1)
~0)(Hc
~0 ® (Wc
~ ±c
c
~ ) (250/1)
~ )(Hc
~ ® (Wc
~c
c
1
1
1 2
~0) (300/1)
~0)(Hc
~0 ® (Wc
~ ±c
c
1
1
1 2
Mbb [GeV]
50 100 150 200 250 300 350 400 450 500
Signal
bin
Combine all
three search
channels.
Limit is very close to the theoretical
cross section. Exclusion below 204 GeV.
50
Search for t and c in H𝛾𝛾 final states
0
SUS-13-014
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS13014
Parallel talk: David Morse
• Up until now, CMS searches for GMSB photon signatures
have been searches for inclusive Jets + MET + 1-2 photons.
• Now look for naturalness motivated signature in GMSB
b
350
300
CMS Simulation Preliminary
-1
òL dt = 19 fb
s = 8 TeV
10
1
10-1
b
500
JET
JET
250
G
200
150
1
H
400
c
c- c
300
G
H ® gg
0
1
0
1
Stop Mass (GeV)
tR
c1+
JET
JET
200
tR
Higgsino Mass (GeV)
Strong +EWK production
Cross Section x br[h® g g ] (fb)
• 𝜎×B(H𝛾𝛾) can lead to significant number produced events!
• QCD background: 𝛾𝛾 + bb & 1𝛾 + bb + jet faking 𝛾.
51
Search for t and c in H𝛾𝛾 final states
0
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS13014
SUS-13-014
Parallel talk: David Morse
• Selection: 2 photons (isolated, ET>40, 25 GeV), ≥2 b-jets
(pT>30 GeV).
• Use H𝛾𝛾 mass sidebands to predict background MET
distrib.
• Normalize to number of events obtained from fit to M(𝛾𝛾).
• 3 samples: 2 b-jets
with M(bb)~M(H); ≥3 b-jets;
other.
Higgsino
Mass (GeV)
Events per bin
350
300
250
200
CMS Preliminary
-1
s = 8 TeV
Excluded
region
òL dt = 19 fb
ò
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
-1
100 120 140
s = 8 TeV, L dt = 19 fb
80
400
500
Stop Mass (GeV)
60
s (Expected)
s (Expected ± 1s exp.)
s (Observed)
s (Observed ± 1s theory)
300
CMS Preliminary
Stop
40
Higgs Mass Region
Data Driven Background
MC Signal: M =350, MHiggsino=135
Stop
MC Signal: M =400, MHiggsino=300
Stop
MC Signal: M =300, MHiggsino=290
20
ETmiss (GeV)
MC signals peak at high MET
150
200
30
25
20
15
10
5
0
0
Data in Higgs
mass window
Background
Observed Excluded Cross Section (pb)
52
Outline
• Big themes and challenges for
SUSY searches
• Inclusive (generic) searches
• Naturalness-inspired searches:
t , b, g
• Search for EWKinos & sleptons
c , c ,
0
i
±
j
• SUSY decays with Higgs
• Multi-leptons and R-parity
violating signatures
• Conclusions
Drawing courtesy Sergio Cittolin
CMS PUBLIC SUSY RESULTS
https://twiki.cern.ch/twiki/bin/vie
w/CMSPublic/PhysicsResultsSU
S
New results in all of these areas.
Analyses use 19.5 fb-1 (√s =8 TeV).
53
Multi-lepton and R-parity violating processes
SUS-13-002, 13-008
Andrea Gozzelino (multilepton)
SUS-13-003, 13-010, 13-013, EXO-12-049 Matthew Walker (R-parity violating)
Multi-lepton and R-parity violating processes
SUS-13-002, 13-008
Andrea Gozzelino (multilepton)
SUS-13-003, 13-010, 13-013, EXO-12-049 Matthew Walker (R-parity violating)
Common theme: powerful signatures that strongly suppress ttbar
and other SM backgrounds. Typically have loose/no MET cuts!
 Access to compressed spectra and R-PV SUSY.
55
Multilepton searches with R-PV interpretations
Matthew Walker (R-parity violating)
Same-sign
dileptons + b-tags
≥3 leptons + btags
4 leptons
(SUS-13-013)
(SUS-13-003)
(SUS-13-010)
2
1.5
1
0
0.5
1000
800
600
400
10
-
l ¹0
122
m~q exclusion
m~g exclusion
LSP ® l+l n
eISO Î [0.5, 1]
l ¹0
121
m~q exclusion
m~g exclusion
expected exclusions
m~t exclusion
0.6
m~t exclusion
0.4
900
600
800
-1
s = 8 TeV, L dt = 19.5 fb
ò
56
1100
1200
m~t (GeV)
-1
L=19.5 fb , s = 8 TeV
²
1000
mgluino (GeV)
1200
pp ® ~g~g, ~g ® tbs, l323
observed 95% CLs Limits
expected 95% CLs Limits
expected ±1s
expected ±2s
Theoretical sNLO
Theoretical ±1s
1000
0.8 1 1.2
mLSP (TeV)
observed 95% CLs Limits
Theory uncertainty (NLO+NLL)
expected 95% CLs Limits
expected ±1sexperimental
800
400
CMS Preliminary
200
106
105
104
103
102
700
1200 Stop RPV l122
CMS
0.2
Results from
4𝜇 & 4e similar
1
200
m( c10 )
m(t )
m(g)
m( c10 )
1
s (fb)
Exclude stop
masses
up to ~1 TeV
Exclude masses
up to ~900 GeV
(Te
95% CL mass UL
m~
0* (GeV)
c
s (fb)
neutralino RPV decay
direct stop with
RPV decay
gluino RPV decay
Multilepton searches: general
Andrea Gozzelino talk
SUS-13-002
SUS-13-008
Search for anomalous lepton
production
• ≥3 leptons (e, 𝜇, 𝜏)
• Binning in
N(lep), N(𝜏), N(b-jet)=0, ≥1,
MET, HT, OSSF pairs,
on Z/off Z
Search for events with
≥3 leptons, ≥2 jet, ≥1 b-jet.
• 3(e, 𝜇)
• Binning in
• N(lep), N(jets), N(b-jets),
MET, HT, on Z/off Z
Sbottom pair production
b1 ® t c1-
GMSB natural higgsino NLSP scenario
m~
± (GeV)
c
1
700
600
500
400
300
200
CMS Preliminary
500
Theory uncertainty (NLO+NLL)
400
expected 95% CLs Limits
expected ±1sexperimental
300
2
Natural Higgsino NLSP (GMSB)
~
0
Br(~c ® ZG) = 1, Strong and Weak Production
1
observed 95% CLs Limits
200
mc~0 = mc~± - 5 GeV, m~0 = mc~± + 5 GeV
c
1
1
1
ò
700
-1
800
s = 8 TeV, L dt = 19.5 fb
600
m~t (GeV)
57
Conclusions
• Over the first 3 years of LHC running, we have developed
a broad SUSY program, with an extensive set of searches.
• There is no evidence for a signal in any search.
• The overall behavior of SM backgrounds in the data
sample appears to be well understood.
• Searches for gluinos and squarks are highly developed.
• There is significant progress in developing searches for
EWKinos.
• Compressed spectra represent a challenge.
• Interpretation is complex; much ongoing work.
• We expect very substantial gains in the discovery reach
for the upcoming run.
58
Backup slides
from Frank Golf talk
from Frank Golf talk
5σ discovery curves
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS13006
SUS-13-006
Slepton exclusion region
WZ+MET: search
complementarity
1
c
1
c
CMS Preliminary
L L
300 pp ® ~eL ~eL, m~ m~
1
250
~ 0
Br (lL ® l ~c ) = 1
200
150
100
50
0
~
<
m c1
1
mZ
int
L = 19.5 fb-1, s = 8 TeV
95% C.L. CLs NLO Exclusions
Observed ± 1stheory
Expected ±1sexperiment
250
300
l
m~ (GeV)
400
(GeV)
350
95% C.L. CLs NLO Exclusions
Observed 2l2j Å 3l ±1stheory
Expected 2l2j Å 3l ±1sexperiment
Expected 2l2j Å 3l -2sexperiment
Observed 3l only
Observed 2l2j only
L = 19.5 fb-1, s = 8 TeV
int
0
100 150 200 250 300 350 400 450
-
200
CMS Preliminary
0 ±
2 1
pp ® ~c ~c
1
0
150
mc2
~
~c± ® W ~c0
~0 ~0
200 c2 ® Z c1
150
100
50
0
100
2
m ±=m 0
c~ ~c
1
102
10
1
103
102
95% C.L. upper limit on cross section (fb)
95% C.L. upper limit on cross section (fb)
(GeV)
m~0
(GeV)
m~0
±
j
Electroweak production: c , c ,
0
i