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Moriond QCD week 18-24 March 2001. Other Searches at LEP. Sylvie Braibant CERN. RPV-SUSY GMSB Technicolor Excited leptons Leptoquarks. Searches Variants. • R-parity conserving SUSY (LSP stable Æ missing energy) • Standard SUSY: neutralino LSP (see T. Alderweireld’s talk)

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Other searches at lep

MoriondQCD week

18-24 March 2001

Other Searches at LEP

Sylvie Braibant

CERN

RPV-SUSY

GMSB

Technicolor

Excited leptons

Leptoquarks


Searches variants
Searches Variants

• R-parity conserving SUSY

(LSP stable Æ missing energy)

• Standard SUSY: neutralino LSP

(see T. Alderweireld’s talk)

• GMSB: gravitino LSP G

• light G (eV Æ GeV) with possibly long lifetime of

slepton or neutralino NLSP: either c1 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

~

~

~

~

0

~

Sylvie Braibant - CERN


Rpv susy superpotential
RPV SUSY: Superpotential

Sylvie Braibant - CERN


Rpv susy r parity
RPV SUSY: R-Parity

• Assumptions • exactly 1l-like coupling different from 0 at the time

• mean path of flight < 1 cmÆ l> 10-4

Sylvie Braibant - CERN


Rpv susy production mechanisms
RPV SUSY: Production Mechanisms

Sylvie Braibant - CERN


Rpv susy gaugino searches
RPV SUSY:Gaugino Searches

Sylvie Braibant - CERN


Rpv susy gaugino searches for l

mc1 > 40 GeV

~

0

RPV SUSY: Gaugino Searches for l

Sylvie Braibant - CERN


Rpv susy gaugino searches for l1
RPV SUSY: Gaugino Searches for l’

Final states contain many jets and leptons

Sylvie Braibant - CERN


Rpv susy gaugino searches for l2

mc1 > 38 GeV

~

0

RPV SUSY: Gaugino Searches for l’’

Final states with up to 10 jets

Sylvie Braibant - CERN


Rpv susy slepton searches
RPV SUSY: Slepton Searches

Sylvie Braibant - CERN


Rpv susy slepton searches mssm limits
RPV SUSY: Slepton Searches - MSSM limits

l’’

l

Similar results for squarks, sneutrinos for RPV l, l’, l’’ decays

Sylvie Braibant - CERN



Rpv susy
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

Sylvie Braibant - CERN



Gmsb susy searches
GMSB SUSY Searches

Sylvie Braibant - CERN


Gmsb susy searches neutralino nlsp

l

0

GMSB SUSY Searches: Neutralino NLSP

L << LDet

Acoplanar photons

Zero Lifetime

L ~ LDet

Single non-pointing photon

Non-zero Lifetime

Sylvie Braibant - CERN


Gmsb susy searches neutralino nlsp1
GMSB SUSY Searches: Neutralino NLSP

Acoplanar photons

Zero Lifetime

Sylvie Braibant - CERN


Gmsb susy searches neutralino nlsp2
GMSB SUSY Searches: Neutralino NLSP

Non-pointing

single photons

Non-Zero Lifetime

Sylvie Braibant - CERN


Gmsb susy searches slepton nlsp
GMSB SUSY Searches: Slepton NLSP

l

0

Zero Lifetime

Acoplanar leptons

Exclusion plots for

Sleptons in gravity-mediated

Heavy stable charged

particles

dE/dx

or

RICH detectors

Large IP + kinks

Large IP Æ L=O(1 mm)-O(40 cm)

Kinks Æ L=O(10 cm)-O(2 m)

Sylvie Braibant - CERN


Gmsb susy searches slepton nlsp1

~

Combining searches in various regions of l lifetime

GMSB SUSY Searches: Slepton NLSP

Intermediate lifetime

Searches for large

impact parameters+

Searches for kinks

Sylvie Braibant - CERN


Gmsb susy searches sgoldstino

s - mf

2

Eg =

2 √ s

GMSB SUSY Searches: Sgoldstino

e+e-Æ fg

Depends on mf and √ F

Most relevant decays:

f Æ gg (4-11%)

f Æ gg (96-89%)

M1 M2 M3

1) 200 300 400

2) 350 350 350

Sylvie Braibant - CERN


Technicolor

• Provides a scheme to generate W/Z masses. EW symmetry broken dynamically by strong interactions of gauge bosons.

• Introduces new technifermions

which obey a QCD-like

Interaction with an effective scale LTC >> LQCD

• At LTC , TC interation becomes strong Æ 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 technidoubletsÆ additional scalar (pT, p’T) and vector (rT, wT) mesons which can be light enough to be observed at LEP2.

TVa

TDa

Technicolor

_

Sylvie Braibant - CERN


Technicolor1

- broken dynamically by strong interactions of gauge bosons.

e+e-ÆrTÆ ff (below WW threshold)

e+e-ÆrTÆ W+W- (above WW threshold)

-

-

Important decays pT+Æ bc, bu

Technicolor

rTÆ W±pT±, pT0g

rTÆpT-pT+

Sylvie Braibant - CERN


Technicolor2
Technicolor broken dynamically by strong interactions of gauge bosons.

No significant contribution of technicolor production is observed

Æ 95% CL exclusion region in the (MrT, MpT) plane

Sylvie Braibant - CERN


Excited leptons
Excited Leptons broken dynamically by strong interactions of gauge bosons.

Sylvie Braibant - CERN


Exited leptons
Exited Leptons broken dynamically by strong interactions of gauge bosons.

Sylvie Braibant - CERN


Excited leptons1

Flavour broken dynamically by strong interactions of gauge bosons.95% mass limits (GeV)

e* 102.9

m* 102.9

t* 102.8

Excited Leptons

Sylvie Braibant - CERN


Leptoquarks
Leptoquarks broken dynamically by strong interactions of gauge bosons.

Single Production

Pair Production

Sylvie Braibant - CERN


Leptoquarks1
Leptoquarks broken dynamically by strong interactions of gauge bosons.

Production

Sylvie Braibant - CERN


Leptoquarks2
Leptoquarks broken dynamically by strong interactions of gauge bosons.

Vector Leptoquarks

Sylvie Braibant - CERN


Leptoquarks3
Leptoquarks broken dynamically by strong interactions of gauge bosons.

Scalar Leptoquarks

Sylvie Braibant - CERN


Conclusions
Conclusions broken dynamically by strong interactions of gauge bosons.

• 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

Sylvie Braibant - CERN


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