RPV UDD (D. Fouchez)
The selections are the same used at 189 GeV. The data sample presented
correspond to 237 pb-1 (all energies between 192 and 202 GeV). The 4 jets
rate seems to be a bit low (-2.5 sigma),while teher's slight excess in
multijets and multijets + missing E. Y56 variable has a slight excess at
high values. In these conditions a 80% bkg subtraction is reasonably conservative.
Efficiencies have been reduced by 5% to include systematics. The slight
excess of 4 jets + missing E at 200 GeV almost disappeared at 202 GeV.
Limits obtained improve exclusions on sfermion masses of 5-6 GeV with
respect to 189 GeV.
RPV LLE, LQD (David Hutchcroft)
All selections are the same used at 189 GeV. Data is combined at all
energies to produce limits. A slight excess in LLE (llll topologies) has
been found at 200 GeV (8 seen 2.32 expected). LQD has a deficit (at 200
and 202 GeV) in selections which looks at 4 jets at the W peak. Only
80% of the WW background has been subracted in producing the limits. All
limits obtained are better than those at 189 GeV.
Peter Dornan suggested to look at the way charged Higgs group uses
angular momentum cuts to reduce WW. It was decided to send a conf note
for winter conferences on RPV results.
GMSB photons (Single and multiphoton events
at sqrt(s)=189-202 GeV) (G. Taylor)
All results obtaind by Gary have been updated using final data samples.
In the 1 gamma + missing E channel he found 4 events in a low missing mass
region. It seems to be a fluctuation. He checked energy resolution for
both well contained photons and photons in the cracks using collinear gamma
gamma events (it is O.K.). In gamma + missing energy topology Gary obtained
limits on e+e- to gravitino gamma , e+e- to graviton gamma (quantum gravity).
In the 2 gamma + missing E scenario he obtained limits on e+e- to
XX to YY gamma gamma (100% BR X to Y gamma) and produced exclusion
plots for "CDF event" in case of chi LSP and gravitino LSP. Good agreement
between expected(<0.8) and oserved (0) events for non pointing single
photon analysis. The purely QED process e+e- to gamma gamma(gamma)analysis
has a -2.2 sigma deficit mostly due to a big fluctuation at 189 GeV (all
other energies are O.K.). Gary showed also limits on new physics effects
suche as extra dimensions, contact interactions and excited electrons.
Globally all limits obtained are significantely improved over 189 GeV limits.
GMSB stau NLSP scenario (G. Taylor on behalf
of Chris Booth)
The analysis is exactly as before,updated with final data sample and
uses only 192-202 Gev data. Two plots were showed:
1) a slepton mass limit as a function of lifetime for all sleptons
and for the degenerate slepton case:
2) a stau mass limit as a function of lifetime including the 3 separate
analysis (MSSM short lifetime, Kinks and or large d0 intermediate lifetime,
HSCP long lifetime). Only MSSM short lifetime analysis performed
bkg subtraction. At the end it was suggested to produce a conf note on
photons with everything showed by Gary and a separate small conf note for
the sleptons.
Preliminary Results of the MSSM slepton searches
(F. Holldorfer)
Frank used reprocessed data,old MC and efficiencies. Bkg maps
for 192 and 200 GeV were interpolated. There is a small excess ifor the
stau searches at 196 GeV and 202 GeV. He made stau pre-cuts and confronted
the excess in the data with a stau signal, with mstau=85 GeV and some values
of deltaM, and showed that the shape of the signal does not fit with
excess data points in th eMvis plot where the excess is too narrow. The
limits obtained are obviously worst than expected in the stau case while
for the other sleptons are as expected. It was decided to show for winter
conferences the plots of slepton searches exclusions and to give the number
of candidates and expected background. The ALEPH excess in the stau channel
as a significance of the order of 5% (too small to give too mach enphasis
to it).
MSSM Squarks (M. Antonelli)
Mario showed the updated analysis using 192-202 GeV reprocessed data.
He used 189 GeV selection at 192 GeV and reoptimized ones for 196,200,202
GeV. He can obtain in some cases 50% efficiencies. The gamma gamma Bkg
was estimated at 183 GeV.
99 data seems to have some excesses at small visible energies with
respect to W e nu PHYTIA. Using Grace 4-f there is a better agreement
even for CLB. Mario showed the results which are generally 2-4 GeV better
than previous ones. Stop at low deltaM (G. Sguazzoni).
Squarks with lifetime (G. Sguazzoni)
Giacomo presented a new analysis. The decay stop to c chi at small
deltaM can have large lifetime. If mstop < mc + mchi the only possible
decay of the stop in stop tp u chi with a huge lifetime. So he decided
to implement an analysis to look for the stop hadron.
He modified the standard MC codes (for example implementing the stop
hadron behavior in GEANT treating its interaction like massive pi mesons).
The expected background is mainly due to muon tracks (long lifetime) and
cosmic rays tracks (intermediate lifetime). He used all data from 189 to
202 GeV. In the long lifetime scenario he applied dE/dx and kinematics
cut criteria. In the intermediate lifetime scenario he applied cosmic rays
and gamma gamma rejection and cut on missing energy. Combining all selection
efficiencies (standard MSSM low deltaM,intermediate and long lifetime)
and counting systematics he was able to set an absolute lower limit for
all deltaM on stop mass equal to 68 GeV ( to be compared with 77 GeV MSSM
stop benchmarks). Giacomo remarked he didin't assume any relation between
c-tau of stop and deltaM (as happens in MSSM). This permits a conservative
approach.
Addendum: The day after a bug in the efficiency
parametrization was found. The stop mass limits goes down to 59 GeV.
Update of Neutralino Searches at sqrt(s)= 192-202
GeV + LSP limit (F. Gianotti)
Fabiola explained the news from this searches which are:
- use of reprocessed data
- full luminosity implemented in analysis (237 pb-1)
- better understanding of Bkg
- filling "holes" to extract LSP limt for any m0 and tanbeta
Efficiencies are similar to last year. The Bkg is NOT subtracted. She
used GRACE 4-f to extimate W e nu Bkg and it's more compatible with data
with respect to PHYTIA in the intermediate and high deltaM selections.
She is trying to fill the holes with AJ analysis to get LSP limits but
she needs a finer scan; so some days are still required to have results.
Globally she improved the limits from neutralino searches and indirect
limit on chargino mass. It was decided to submit only one paper for the
MSSM searches about chargino,neutralino,sleptons and squarks all together
for winter conferences. Gerri is the main editor of the MSSM paper.
Has LEP discovered the Stau?
(G. Ganis)
Gerri showed the results of stau searches in ALEPH: there's a small
excess (48 seen vs 36.8 expected considering all 189-202 GeV data). Other
experiments observe small excesses too. In the combination several points
in the usual (mstau,mchi) plane have CL
as low as 10-4. However the probability that the expected
Bkg can fluctuate to such a pattern has not been calculated yet.
Looking closer at numbers an excess is present almost at all sqrt(s).
More investigation is needed and it should be important to quote systematics
on estimated Bkg.