Topics for Future SUSY Work
This page lists some possible topics for future work in the ATLAS SUSY
group. Many of these could be suitable topics for a thesis, or in some
cases several theses. To avoid duplication of effort, we suggust that
you consult one of the SUSY convenors before starting to work.
SUSY Points
The study of specific points in SUSY parameter space is a useful
self-contained activity which allows to get experience with the tools
and the analysis methods typical of SUSY searches at the LHC. A full
analysis on an initial set of points has been performed by ATLAS in the
years 1996-99.
A set of new points were proposed at Snowmass in 2001 and are documented
in hep-ph/0202233. The goal for each point is to identify a set of
exclusive measurements which can be performed with ATLAS and to estimate
the uncertainty of the measurements. We give in the following table a
list of the mSUGRA Snowmass points:
|
Point
|
Comments
|
Status
|
| 1a |
Similar to ATLAS
Point 5, somewhat softer.
|
Being studied |
| 1b |
chi20 and chi1+ decay
maintly to tau. Need good experimental control of hadronic tau decays.
Not many signatures.
|
Free |
| 2 |
Focus point region.
|
Being studied |
| 3 |
Coannihilation region with very light sleptons.
chi20 decays to a mixture of leptons, taus, and
higgs. Soft single leptons. Nice signatures, comparatively easy.
|
Being studied |
| 4 |
High tan(beta), so
chi20 -> chi10 Z dominant.
Lots of t,b from gluino decays. Could start with gluino -> b1 ->
chi20 -> chi10 decay chain.
Clear signatures.
|
Being studied |
| 5 |
Very light stop, produced both directly and through gluino -> stop top.
Somewhat hard but instructive.
|
Free |
| 6 |
Non-unified m1, m2, m3.
Chosen to be difficult due to
degeneracy of chi10 with
chi20 and chi1+.
|
Free |
Points similar to the Snowmass GMSB ones have already been studied in
ATLAS. One very important issue needing further study is the measurement
of the NLSP lifetime. This requires detailed detector studies, e.g., of
non-pointing photons or of reconstruction of kinks in the central
tracker.
The AMSB Snowmass has already been studied by the Cambridge group.
Experimental Issues
This list includes topics which are more
directly related to experimental performance, so using full simulation
may be appropriate.
- Try different jet algorithms for reconstructing jet final states.
Understand how to correct the jet energy scale for complex, multi-jet
final states.
- Improve the reconstruction of top, stop, and other multijet final
states.
- Explore systematic effects (particle widths, photon radiation, e/mu
energy scale) for dilepton endpoints.
- Study resolution tails for non-pointing photons in GMSB, including
the effects of extra photons from the event and pileup.
- Study the measurement of the $\tilde\chi_1^0 \to \tilde G \gamma$
lifetime in GMSB models. I.e., how can one determine the $\beta\gamma$
distribution of the NLSP?
- Study detection of NLSP sleptons in GMSB models, including
$\beta<1$ particles in the muon system, kinks in the inner detector,
ionization in the TRT, and track matching.
- Study measurement of the LSP lifetime in R-parity violating models.
- Improve the simulation of the missing energy tails. Note the
characteristic signature of extra dimensions is monojets.
Long-term Projects
These are obviously important but probably
beyond the scope of a thesis.
- Most of our studies to date have relied on kinematic endpoints to
determine masses. There is much more information available in branching
ratios, kinematic distributions, and cross sections. How best to use
this information requires careful thought.
- We have assumed that the SUSY model parameters are all real and
that flavor mixing is absent. This avoids low energy constraints but may
not be realistic. We should relax these assumptions and study their
determination and effects, e.g., signatures of CP violation. No suitable
event generator is currently available.
Frank Paige and Giacomo Polesello
20 November 2002