Moriond QCD week
18-24 March 2001
Other Searches at LEP
Sylvie Braibant
CERN
On behalf of the LEP experiments
RPV-SUSY
GMSB
Technicolor
Excited leptons
Leptoquarks
Searches Variants
• R-parity conserving SUSY
(LSP stable  missing energy)
• Standard SUSY: neutralino LSP
(see T. Alderweireld’s talk)
~
• GMSB: gravitino
LSP G
~
• light G (eV  GeV) with possibly long lifetime
of
~
~0
slepton or neutralino
NLSP:
either
c
1 or l
~
• super-light G (meV)
• R-parity violating SUSY (LSP decays to SM particles)
• vast field with very different signatures
• Exotics
• Technicolor
• Leptoquarks
• Excited Leptons
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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RPV SUSY: Superpotential
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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RPV SUSY: R-Parity
• Assumptions • exactly 1 l-like coupling different from 0 at the time
• mean path of flight < 1 cm l > 10-4
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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RPV SUSY: Production Mechanisms
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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RPV SUSY:Gaugino Searches
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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RPV SUSY: Gaugino Searches for l
m~c01 > 40 GeV
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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RPV SUSY: Gaugino Searches for l’
Final states contain many jets and leptons
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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RPV SUSY: Gaugino Searches for l’’
Final states with up to 10 jets
m~c01 > 38 GeV
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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RPV SUSY: Slepton Searches
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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RPV SUSY: Slepton Searches - MSSM limits
l’’
l
Similar results for squarks, sneutrinos for RPV l, l’, l’’ decays
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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RPV SUSY: Sneutrino Searches - Resonant Production
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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RPV SUSY
• Searches for Rp-violating production and decay of SUSY
particles are complementary to searches with Rp-conservation
• Under the assumption of Rp-violation, searches have been
performed for gauginos, sleptons, sneutrinos and squarks for
all Yukawa couplings l, l’, l’’
• No evidence for SUSY with Rp-violation
• Exclusion limits are similar to the Rp-conserving case
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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GMSB SUSY Searches: Light Gravitino Scenarios
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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GMSB SUSY Searches
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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GMSB SUSY Searches: Neutralino NLSP
l
0
L << LDet
L ~ LDet
Acoplanar photons
Zero Lifetime
Single non-pointing photon
Non-zero Lifetime
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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GMSB SUSY Searches: Neutralino NLSP
Acoplanar photons
Other Searches at LEP - Moriond 2001
Zero Lifetime
Sylvie Braibant - CERN
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GMSB SUSY Searches: Neutralino NLSP
Non-pointing
single photons
Other Searches at LEP - Moriond 2001
Non-Zero Lifetime
Sylvie Braibant - CERN
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GMSB SUSY Searches: Slepton NLSP
l
0
Zero Lifetime
Acoplanar leptons
Exclusion plots for
Sleptons in gravity-mediated
Other Searches at LEP - Moriond 2001
Large IP + kinks
Large IP L=O(1 mm)-O(40 cm)
Kinks L=O(10 cm)-O(2 m)
Sylvie Braibant - CERN
Heavy stable charged
particles
dE/dx
or
RICH detectors
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GMSB SUSY Searches: Slepton NLSP
~
Combining searches in various regions of l lifetime
Long lifetime:
Searches for heavy stable
charged particles
Zero lifetime:
Search for prompt decays:
acoplanar lepton search
Intermediate lifetime
Searches for large
impact parameters+
Searches for kinks
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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GMSB SUSY Searches: Sgoldstino
e+e- 
Depends on m and √ F
Most relevant decays:
 (4-11%)
gg (96-89%)
E =
1)
2)
s - m2
2√s
M1
M2
M3
200
350
300
350
400
350
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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Technicolor
• Provides a scheme to generate W/Z masses. EW symmetry broken
dynamically by strong interactions of gauge bosons.
• Introduces new technifermions
TVa
TDa
which obey a QCD-like
Interaction with an effective scale LTC >> LQCD
• At LTC , TC interation becomes strong  techniquark condensates replace
non zero VEV of Higgs field:
_
<TT> = Fp ~ 246 GeV
• Extensions are worked out to solve problems:
• These extensions call for a large number ND of technidoublets  additional
scalar (pT, p’T) and vector (rT, wT) mesons which can be light enough to be
observed at LEP2.
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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Technicolor
e+e-
rT  ff
-
(below WW threshold)
e+e- rT  W+W-
(above WW threshold)
rT  W±pT±, pT0
rT pT -pT+
Important decays
Other Searches at LEP - Moriond 2001
pT+
-  bc, bu
Sylvie Braibant - CERN
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Technicolor
No significant contribution of technicolor production is observed
 95% CL exclusion region in the (MrT, MpT) plane
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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Excited Leptons
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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Exited Leptons
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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Excited Leptons
Flavour
95% mass limits (GeV)
e*
m*
t*
Other Searches at LEP - Moriond 2001
102.9
102.9
102.8
Sylvie Braibant - CERN
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Leptoquarks
Single Production
Other Searches at LEP - Moriond 2001
Pair Production
Sylvie Braibant - CERN
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Leptoquarks
Production

l
LQ
LQ
q
q
BR = 1 - 
BR = 
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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Leptoquarks
Vector Leptoquarks
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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Leptoquarks
Scalar Leptoquarks
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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Conclusions
• LEP has been a great success until its very end
• A broad spectrum of new particle searches have been and are
actively pursued… but no indication for Physics beyond the SM
• Results are interpreted in various models
• Existing limits have been extended:
plenty of preliminary results using all the data collected
at LEP
LEP SUSY working group combining results on:
GMSB and RPV
LEP exotica working group starting to combine results on:
single top, excited leptons, leptoquarks
• We are working towards FINAL LEP results
• Apologies for results which were not shown
• Many thanks to my LEP colleagues who helped me to prepare this
talk
Other Searches at LEP - Moriond 2001
Sylvie Braibant - CERN
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