Systematic analysis of
frontier energy collider data
Hamburg, Germany
Geneva, Switzerland
The Game
Strategy and tactics
Batavia, IL
Implications
Bruce Knuteson
MIT
Moriond QCD
17 March 2005
The first sign of new physics will come from:
7
Heavy gauge bosons
11
Technicolor
21
Large extra dimensions
3
36
Leptoquarks
Supersymmetry
5
Fourth generation fermions
6
Compositeness
11
Something else
The values of the 105 MSSM parameters are:


mQ~  






mL~  





M1


yu  




au  






 yd  








 ad  








 ye  








 ae  


















mu~  








md~  








m~e  









M2
M3
mH2 u
mH2 d
b
“Discovery” with a typical search
Remember that George will guess wrong
But let’s say George is very lucky and guesses close . . .
true signal
George's guess
3.5
George's “modified” guess
6.5
y
an "event"
(pp collision)
x
How should George interpret this? (Will anyone believe him?)
Moral: Any “successful” dedicated search is bound to end up in a set
of highly sculpted cuts, since the original guess will be wrong.
true signal
George's guess
3.5
George's “modified” guess
6.5
y
an "event"
(pp collision)
x
The Game
Maximize chance for discovery before LHC turn-on
Maximize chance for discovery after LHC turn-on
Strategy and tactics
in brief
1
Vista
Model-independent search for new
large cross section physics
Gross features,
bulks of distributions
Define physics objects

e
Simulate detector response
Filter events of interest

b
p
p


Estimate backgrounds
Fit for experimental & theoretical fudge factors
reconstructed
(mis)Id
e    j b
e

true
j


0.91
0.02 0.001 0.07 1e-3
0.87
0.10
0.90
0.81 0.19
j
1e-4 2e-6 3e-3 6e-4
b
1e-3 1e-3 5e-3 8e-4 0.60 0.40
1
2e-3
toy example
2
Sleuth
Quasi-model-independent search for new
high-pT, small cross section physics
Excess on high-pT tails,
with rigorous computation of trials factor
Sleuth@DØ
Phys.Rev.D 62:092004,2000; hep-ex/0006011
Phys.Rev.D 64:012004,2001; hep-ex/0011067
Phys.Rev.Lett.86:3712,2001; hep-ex/0011071
# events
H1 General Search
Phys.Lett.B 602:14-30,2004; hep-ex/0408044
3
Quaero
Model-dependent hypothesis testing
Rigorous, fast, transparent, robust, and
automatic testing of specific hypotheses
TurboSim
A fast simulation that tunes itself
to any experiment’s full simulation
√ TurboSim@
TurboSim
GeantSim
Full Simulation: 10 s/event
TurboSim: 10 ms/event
4
Bard
Model construction
Automate theorists
Hint from Vista or Sleuth
e+e- bb
Use Quaero to determine
parameters & quantify
goodness of fit
 pT
Generate many possible signals
s
Order resulting list
Current scorecard
Quaero
Vista
Algorithm























*no collaboration commitments

Legend
 published
 technically complete
 work ongoing
 stalled
Bard

Implications
vs.
There could be a clear winner
Astro is ahead of HEP
Bio is ahead of HEP
PHOBOS
nucl-ex/0406021
nucl-ex/0301017
HIP is ahead of HEP
We are beginning to automate the scientific method
Summary
You can’t guess right
guaranteed surprise
In light of this, a few of us are taking a different approach
• Gather all data
• Look at them
Vista
• Look at them again
Sleuth
• Automate hypothesis testing
Quaero
• Interpret underlying physics
Bard
(model independent)
(quasi model independent)
(model dependent)
(model construction)
Systematically maximize chance for discovery
Thanks to:
Appendix
Bard
e+e- bb
 pT