Minutes of SUSY meeting Wednesday 4 May 2000
First look at y2k data
General comments: L~13pb-1 at <Elep>~204 GeV.
Bkg extrapolated from 202 MC.
Rpv topologies UDD, LQD and LLE (D.Fouchezs and D.
Hutchcroft):
Luminosity analyzed at Ecm=203 -> 208 GeV:
7.2 pb-1 for LLE and LQD (17 Topologies)
12.4 pb-1 for UDD
( 8 Topologies)
No excess found. Slight discrepancy in the UDD "Multi-jets + lepton"
topology where 3 candidates are observed for a background of 0.7 expected.
At 202 GeV in 99 we had 9 candidates with a bkg of 3.85. They'll keep an
eye on this channel.
Some shape variables have been checked at the preselection level (like
Y56) .... good agreement DT-MC.
GMSB topologies with photons (G.Taylor):
Lose preselection applied (class 2) provisionally. Results:
DT MC
single g + Emiss
34 41
2g + Emiss
3
3
GMSB 2g
0 0.7
MSSM 2g
1 1.4
QED 2g
106 114
Good agreement data SM bkg also at the level of shapes (missing mass,
energy and angular distribution).
GMSB stable sleptons + check on electron ID (F.Cerutti):
About 13pb-1 of y2k data analyzed.
First look at P scale, Acollinearity and dE/dx on non-radiative dimuons:
agreement DT MC quite good. The distribution of |P1-P2|/s(P)
is slightly larger in the Data. Expected bkg is 0.06, 0 candidates found.
Check of RT and RL variables used in electron ID: Selected Bhabhas
and applied the same cut used in stau analysis (100>RT>-2.4 and 3>RL>-2.4).
Electron ID checked in bins of P and cos(theta). In the central region
of the detector (|cos(theta)|<0.85) the agreement is always better than
2 %. In forward region discrepancies up to 6% found. To be cross
checked with other physics groups.
MSSM squarks (M.Antonelli):
About 13pb-1 of y2k data analyzed. Different variables (Mhad/Elep, Mtot/Elep,
Thrust, Acopt, Eletpon-lead/Elep, b-tag) checked on preselected events
(Mainly qq(g) and WW); good agreement found for all the variables but the
b-tag.
Results:
MC DT
stop -> c chi
0.6 1
stop -> b l snu
0.2 0
sbot -> b chi
0.2 0
MSSM neutralinos and charginos (L.Serin and P.Azzurri):
About 13pb-1 of y2k data analyzed.
Neutralinos. AJ topologies looked at:
delta-M<25 GeV 0 candidates (bkg 0.06), 25<delta-M<40 GeV 0 candidates
(0.03 bkg), Large delta-M 3 candidates (bkg 1.6).
Charginos.For the W* BR analyses 0 candidates
for an expected bkg of 0.66; for the generic BR analyses 1 candidate (selected
by acoplanar-lepton lepton-tau topology) with an expected bkg of 1.92 events.
MSSM sleptons (B.Clerbaux):
About 14pb-1 of y2k data analyzed.
Results:
MC
DT
Selectron
2.51
4
Smuon
2.52
5
Staus
1.98
6
Staus, cross check on 4-Fermion generators performed: Wenu Pithya
vs Grace-4F less bkg predicted by G4F.
Submitted by: Fabio Cerutti