"Beyond the Third Generation: The Search for New Phenomena at D0"
Adam L. Lyon
Aspen Winter Physics Conference - January 13, 1996

Note that the postscript is degraded from the original because the
original postscript from my Macintosh was not viewable by Ghostview.
I have the original postscript files if anyone wants them.

All LEP limits are previously published from LEP 1.

All analyses are from run 1a except for right handed W.

A * after the slide number indicates that the slide was not shown
during the talk.

SLIDES.......

1)  Title slide.  The postscript direct from my Mac looks much cleaner.

2)  Outline:  The red stars show what analyses had just submitted
papers to PRL.

3)  Detector picture.

4)  Supersymmetry description.

-)  Dan's hand drawn MSSM particle content slide was shown here.

5)  Supersymmetric models (MSSM & SUGRA) and R-parity conservation.

6*) Picture of the D0 calorimeter.

7*) Details of 1992-1995 runs.

8)  Search for the process p pbar -> lightest chargino and second
lightest neutralino (W1/Z2) via trileptons.  Cross section plot is
shown as well as decay description.

9)  W1Z2: Isajet signal distributions are shown.  Shaded region is what
is cut by imposing a MINIMUM 5 GeV lepton Pt requirement (the Missing Et
plot shows a 10 GeV MEt requirement only for the eee channel).  The
actual cuts on the first and/or second leptons are 2 GeV over the
trigger/filter threshold.  For example, an eee event collected by the
single EM cluster trigger (20 GeV Et requirement) must have it's
leading electron over 22 GeV and the remaining highest two over 5 GeV.
The third lepton Pt requirement is never over 5 GeV.

10)  W1Z2: Lists triggers used (note I left out the dielectron trigger
by mistake).  The table shows luminosity collected for each channel,
number of events passing cuts, and expected backgrounds.

11)  W1Z2: Details backgrounds of the analysis.  Plot shows signal
efficiencies.  Note the errors on those lines are >= 10% so the fact
that the eee line falls below the others at small W1~ mass is of no
concern.

12)  W1Z2: Cross section * branching fraction limit.  Note the
branching fractions for each channel were considered to be identical:
BF(eee) = BF(ee mu) = BF(e mu mu) = BF(mu mu mu).  The colored bands
indicate theoretical results from isajet by specifying a wide variety
of SUGRA parameters (shown on slide).  The orange band shows the cross
sections from ISAJET with those parameters combined with a branching
fraction of 1/9th.  That is to say the chargino and neutralino decay
purely leptonically and lepton universality is applied.  The blue
(pink) band shows results from cross sections AND branching fractions
from ISAJET for tan beta = 2 (4).

13*) W1Z2: Divide out the cross section from the xs*BF limit and what
remains is a limit contour for the branching fraction alone.  The
shaded region indicates what is excluded for BF < 1/9 (the "maximum" BF).

14*) W1Z2: Lepton quality cuts.

15)  Search for scalar top.  Assumptions and signatures.  Note model
independence.

16)  Stop: Cross section (Baer and ISAJET).

17)  Stop: Signal distributions from ISAJET for various scalar top / LSP
masses.

18)  Stop: Data collected, single interaction requirement, background
and data table.

19)  Stop: Mass limit contour.

20)  Search for squarks and gluinos.  Details of analyses.

21)  SQGL: Squark & Gluino mass limit contour.

22*) Stop: Jet angle cuts.

23*) Stop: Plot showing data and background vs. MEt cut.

24)  Search for right handed W's.  For the large mixing case, W_L
stands for the lighter W.

25)  WR: Details of the Jacobean peak search.

26)  WR: Jacobian peak fits.  Background W/Z from Pythia, QCD from
collider data.  The green stars indicate what we expect the data
should look like if there existed a 400 GeV/c^2 WR with a 200 GeV/c^2
right handed neutrino (simulated by Pythia).

27)  WR: Details of the eejj counting analysis.  

28)  WR: Right handed W mass limit.  
         !!! Note the 720 GeV/c^2 limit is also a limit on W-prime !!!

29)  Table showing results from other D0 New Phenomena analyses.

30*) 4th Generation neutrino limit.

31*) Z-prime limit.

32*) 1st generation leptoquark limit.

33*) 2nd generation leptoquark limit.

34)  List of some analyses in the works.

35) "...D0 has a very active new phenomena program.  It seems that we are
still in the neighborhood where the Standard Model rules.  Perhaps
there is something new waiting for us 'just around the corner' or
further down the street.  In any case, D0 will continue to search for
new phenomena."

The talk fit in the alloted 35 minutes exactly.