Mario
Antonelli and Giacomo Sguazzoni: the stable and quasi stable stops
If you assume that delta M
is small (stop->c chi, or even if that is forbidden stop->u chi) then stop
may have long lifetime. Two searches have been developed: one for two very
heavy charged tracks, one for one track with a high d0. Both have efficiencies
of 10-20%, so limits are about 77-87 GeV for differing lifetime assumptions.
However there is still a corridor at delta M of about 2 GeV for cases where
the life time is too short to always decay outside the detector, but to
long to give only one kink. This is being worked on and may improve, also
only 189 and 192 data have been used so far.
Jean-Baptiste
de Vivie: Higgs Boson Searches and the mass limits on the lightest neutralino.
First he reminded us that
Higgs searches are indeed very constraining. This has been shown inthe
183 GeV Chargino/Neutralino paper. However, before this year, they could
not contribute to improve the absolute lower bound on the LSP mass. With
the new limit on mH (mH>105.6 GeV), and taking into account new corrections
in the theoretical calculations, the tanb range [0.8,1.8] is excluded,
in the improved benchmarks. Assuming the effect of more general scans is
to shrink this range to [1,1.5] this simply translates into a improved
LSP mass limit from 36.5 (set at tanb = 1) to 44 GeV (set at tanb
= 1.5) (assuming low sfermions masses lead to similar limit at high
tanb). Nevertheless, there exist very fine-tuned
configurations where stops
are light and Higgs boson decays into stops. Since no analysis exists to
deal with stable or metastable stops in Higgs decays, no constrains can
be obtained in those cases. This was already present at 183 GeV, but "solved"
by making the further hypothesis (reasonable as soon as it is clearly stated)
that Dm = m(stop)-m(LSP) > 2-5 GeV. Such situation may also decrease the
LSP mass limit obtained from charginos since they also decay into stop,
and there is no missing energy (the basic quantity) in the final state.
The conclusion of all this is that Higgs constraints should at least be
quoted, even if an assumption on Dm has to be made. Moreover, as soon as
Mario and Giacomo manage to close the Dm < 5 GeV region in direct searches
for stop (see above), the stop loophole will disappear.
Dominique
Fouchez: RPV results
Still running reprocessed
data. Also the code to generated RPV ntuples is being merged to have one
"mega"-ntuple (this does include chaminou for the RPC people).
David
Hutchcroft (that's me by the way): RPV status
183 GeV data has been published,
the 189 GeV data should have a draft ready by ALEPH week in January 2000.
A conference note will be written on the 192-202 GeV data taken this year
for the winter conferences, however this will be combined with data taken
next year for a final paper, tentatively planned for January 2001.
On the RPV status for LLE and LQD, there are several new events in 192
that should have been passed in the old reprocessing. These are concentrated
into a three runs, I'm trying to find out why they did not pass/were not
run last time. The 4 lepton excess went up by one at 200 GeV and there
are no events in any cuts at 204 GeV.
Luke
Jones: chi -> slepton lepton (slepton with lifetime)
This is the GMSB case of neutralino->
lepton slepton -> l l Gravitino. The sleptons are assumed to have a lifetime
corresponding to the size of the detector. The pure selectron and smuon
cases are finished, these were relatively simple. The two stau case is
much harder as the higher multiplicity and softer final tracks are much
more like the detector effect high d0 objects. Luke has written code to
identify and eliminate:
- nuclear interactions
- photon conversions
- ECAL splashbacks (tracks created by particles interacting in the ECAL
and coming back into the TPC).
- ITC-TPC track breaks
- Other reconstruction errors
- Cosmics
Three data events which
show these feature were shown. The 2 stau case is now almost complete and
the mixed cases should be quick. A preliminary note is hoped for the beginning
of February. If it is ready in time this may be part of a GMSB note for
la Thuile (see the publication strategy at the end).
Marcello Maggi: chargino searches with lifetime (the transparencies were in Italian, apologies where mistakes are made). With very very low delta-M the ratio of hadronic to leptonic decays changes quickly as a function of delta M and the number of pions produced also varies. Tagging ISR photons was shown to be not sensitive to delta-M and has a higher efficiency.
Gerardo
Ganis: LEPSUSY working group status report
It has been agreed with the
PDG to include the LEP combined data. The results from each collaboration
must have a CERN/EP number and have been accepted by the Journal. So any
results not in that state by January 31st (possibly stretched to February)
will not be included. L3 and Delphi's results are all already in this state,
OPAL does not have any photon results and ALEPH may have photon results.
All of the slepton and squark results are ready.
All
together: Plans for publications and winter conferences
Then there was a general discussion
about publications.
Situation
189 GeV data:
MSSM
slepton and squarks published
MSSM
chargino and neutralino not published: plans are to have a draft
with the 192-202 GeV data included, ready by the end of January beginning
of February (should this also include the impact of the higgs exclusion
on LSP limit ?) .
GMSB
published
RPV
draft 0 ready by end of January
Situation
192-202 GeV data:
MSSM
slepton and squarks: conference note will be ready in January. If
the work on stable stops is finalized soon, it would deserve a publication
(which should naturally include all slepton and squark results at 192-202
GeV).
MSSM
charginos and neutralinos: included together with the 189 GeV results
in a publication.
GMSB
sleptons and photons: the plans are to have a winter conference
note with typical GMSB topologies. If cascade topologies with lifetime
are finalized a publication on GMSB with this year data is possible. If
not maybe worth to wait for next year data before to have a final publication
(including scan).
AMSB
(charginos at very small delta-M): This is
a new analysis and would deserve a separate publication when ready.
RPV
note for winter (and summer) conference. Wait for next year
data for publication.
All this will be reviewed in January anyway, when more analyses will be nearly finished. There was some support for the idea that the scans etc should only be published with next years data.