1. News from ~1fb-1 of e+e- data at Ecm=192-202 GeV
Nikos Konstantinidis
UC Santa Cruz

2. Nikos Konstantinidis - News from LEP
Outline
New physics in SM processes
photons, WW, ZZ…
Direct searches
Higgs and SUSY
The future
LEP at Y2K, after LEP?
Aspen 2000
Nikos Konstantinidis - News from LEP

3. LEP in 1999 - A story of success!
253 pb-1
Aspen 2000
Nikos Konstantinidis - News from LEP

4. LEP operator: Not an easy job!
Cryogenics operated
at limit capacity!
<Fill time>
2.7 hours
RF cavities operated at
~<7 MV/m> well above their design gradient (~6MV/m)
2.1 hours
1.6 hours
Aspen 2000
Nikos Konstantinidis - News from LEP

5. For what follows... 235 pb-1/expt Emphasis on 30 pb-1 at 191.6 GeV
Results very preliminary!!!
(presented one day after the end of run)
Emphasis on
open questions after the ADLO presentations
implications of the latest results
Limits at 95% C.L. - Discoveries at 5s
Aspen 2000
Nikos Konstantinidis - News from LEP

6. Final states with photons
Topology
SM process
New processes
Anomalous TGC’s
Extra dimensions
Single photon
Single ISR
Two acoplanar
photons
Double ISR
SUSY (GMSB)
Extra dimensions
Excited leptons
Contact interactions
Two coplanar
photons
QED t-channel
electron exchange
Aspen 2000
Nikos Konstantinidis - News from LEP

7. Nikos Konstantinidis - News from LEP
Results with photons
Acoplanar
photons
Single
photons
584 obs
592 exp
35 obs
34 exp
Aspen 2000
Nikos Konstantinidis - News from LEP

8. vector boson couplings
W/Z pair production
Experimental
precision
challenges
theory(*)
Limits on
anomalous neutral
vector boson couplings
and extra dimensions
(*) hep-ph/
hep-ph/
Aspen 2000
Nikos Konstantinidis - News from LEP

9. Nikos Konstantinidis - News from LEP
DELPHI eeqq excess
mmqq
Mqq~MZ
eeqq
Mqq (GeV/c2)
Mll (GeV/c2)
10 observed / ~1 expected
(in range GeV/c2)
Aspen 2000
Nikos Konstantinidis - News from LEP

10. …not confirmed by others
ALEPH llqq mass spectrum
already studied before the
DELPHI announcement:
No excess!
mmqq
Specific modifications to
approach the DELPHI analysis:
Still no excess!
eeqq
50-56 GeV/c2:
3.5 expected
1 observed
Aspen 2000
Nikos Konstantinidis - News from LEP

11. Nikos Konstantinidis - News from LEP
SM Higgs - A new regime e_ Z e+ Z* H
New in 1999:
- Moving away from MZ
- Covering an exciting mass range
Aspen 2000
Nikos Konstantinidis - News from LEP

12. Nikos Konstantinidis - News from LEP
HZ - Topologies
BR (%)
eff (%)
Bkg’s: ZZ,qq,WW ZZ,WW,qq ZZ,Zee ZZ,WW
Handles: b-tagging Acoplanarity lepton-ID tau-ID
4 jet topol Mmis = MZ isolation b-tagging
b-tagging Mll = MZ
Aspen 2000
Nikos Konstantinidis - News from LEP

13. Nikos Konstantinidis - News from LEP
ALEPH Higgs Rumors
Jun
Aug
Shown to summer
conferences
Sep
Rumors start here…
Nov
… and end here!
Aspen 2000
Nikos Konstantinidis - News from LEP

14. Nikos Konstantinidis - News from LEP
ALEPH Higgs Search
Excess
in data
Cb max = 0.87
Data
compatible
with SM
Deficit
in data
~1 sigma excess
Cb: The compatibility with SM background.
Contains much more information than a mass plot!
Aspen 2000
Nikos Konstantinidis - News from LEP

15. SM Higgs results up to 202 GeV
ADLO: ~109 GeV
(~200 pb-1 only)
(Up to 200 GeV only)
Aspen 2000
Nikos Konstantinidis - News from LEP

16. MSSM - Neutral Higgs bosons
ADLO ‘99
Theory ‘99
ADLO: ~90 GeV
Low tanb region slowly covered:
ADLO: tanb > ~2
MSSM scans show
no pathological points
Beginning of LEP2
Aspen 2000
Nikos Konstantinidis - News from LEP

17. Nikos Konstantinidis - News from LEP
Charged Higgs
Hitting the W wall
Enough luminosity to explore masses above MW (?)
OPAL + DELPHI excess around GeV gone…
ADLO (189 GeV):
77.3 GeV
Aspen 2000
Nikos Konstantinidis - News from LEP

18. SUSY topologies and backgrounds
R-parity conserved: Missing energy +
4 jets jets-lepton leptons jets
Signal event properties and backgrounds depend on:
large DM
small DM
Aspen 2000
Nikos Konstantinidis - News from LEP

19. Nikos Konstantinidis - News from LEP
Cross section limits
Aspen 2000
Nikos Konstantinidis - News from LEP

20. Covering the small DM region
Aspen 2000
Nikos Konstantinidis - News from LEP

21. Higgs searches may have a significant impact on
The LSP mass limit
From chargino
kin. threshold
Higgs searches may have
a significant impact on
the LSP mass limit!
~36 GeV
Aspen 2000
Nikos Konstantinidis - News from LEP

22. Nikos Konstantinidis - News from LEP
Other searches...
Invisible Higgs decays, fermiophobic Higgs
Squarks/sleptons, GMSB with stau as NLSP
Heavy stable particles
Excited leptons
Deviations from SM in 2-f processes
Anomalous TGC’s
Aspen 2000
Nikos Konstantinidis - News from LEP

23. LEP in Y2K - Ultimate reach
202 GeV : Successful operation in 1999
204 GeV : Pilot run (~10nb-1/expt) in 1999
206 GeV : Seems possible in 2000 (obtained in tests)
208 GeV : Optimistic? (but not out of question...)
>210 GeV : forbidden by French law!!!
Standard Model Higgs
Sensitive up to ~ (Ecm-MZ) -> 114 GeV/c2
Charginos
Sensitive up to ~ Ecm/2 -> 104 GeV/c2
MSSM Higgs
h,A close to 95 GeV/c2
charged Higgs: sensitivity above MW
Aspen 2000
Nikos Konstantinidis - News from LEP

24. If no Higgs at LEP? If central value of MH stays as is now,
LEP’s last contribution to the Higgs search is the indirect determination of its mass using the most precise W mass to that date!
“Ball” passed to Fermilab!
If central value of MH stays as is now,
strong motivation for both Tevatron and LHC
to prepare for the most difficult Higgs hunt:
MH ~ 130 GeV/c2
Aspen 2000
Nikos Konstantinidis - News from LEP

25. Summary 1999: a year of excitement and good results
… but negative results!
An outstanding year for LEP concludes
a decade of a successful experimental program
of leading research!!!
Not too late to reward
it with a discovery!!!
Aspen 2000
Nikos Konstantinidis - News from LEP