Muon PRS Group
Darin Acosta
(“Muon Guy”)
University of Florida
September 5, 2000
D. Acosta -- USCMS Physics Meeting
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Who’s Involved?

In Europe:
 Ugo Gasparini et al. – Generator studies, L2
 Norbert Neumeister – DB prodn, L1, L2
 Anna Vitelli – DB prodn, barrel muon reconstruction
 Several others with lesser involvement
In
the U.S. (Endcap Muon group):
 D. Acosta, S.M. Wang (UFlorida) – L1
 R. Breedon, T. Cox (UCD) – geometry, endcap recon.
 B. Tannenbaum (UCLA) – L1
 R. Wilkinson (Caltech) – endcap recon., general guru
September 5, 2000
D. Acosta -- USCMS Physics Meeting
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HLT Milestones
November 1999
 EMU missed completely. Insufficient time to
develop code for geometry, digitization,
persistence, and L1 from scratch in 6 months
 July 2000
 EMU sort of met it. All pieces were in place, and
preliminary results shown, but not enough time for
tuning (PT assignment), debugging, and
optimization (code was too slow for out-of-time
pile-up).
 September 2000
 Close to having all above issues resolved for
dedicated L1 studies for the L1 TDR (due by Nov.)
 But, goal line keeps moving: more demands on L1
trigger threshold definition (90% effic. vs. 50%)

September 5, 2000
D. Acosta -- USCMS Physics Meeting
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U.S. Experience (1)

EMU group works well together
 Lots of e-mail exchanges, video conferences, and
meetings to keep everyone informed and on-track
 A real user group where you can post a message
(even dumb ones) and get help
EMU code development for ORCA is entirely a U.S.
effort, with only minor consultation from Anna,
Norbert, Vincenzo,…


We are heartened by Sarah’s comments:
 “US muon has this [ORCA experience], which is one of the
reasons I think they are so successful!”
Because…
September 5, 2000
D. Acosta -- USCMS Physics Meeting
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U.S. Experience (2)

This development has been painful:
 Large C++/ORCA/SCRAM learning curve to climb
(makes it hard for newcomers to contribute)
 ORCA is a moving target:
Version doesn’t stay stable long enough to finish bug
fixes, tuning, and collect results.
 e.g. ORCA3  ORCA4 was a major switch after the
November 1999 HLT meeting. It took many months before
basic code was ready, which left little time for L1
developers to complete their work. We still had to rush for
the July HLT meeting despite it being 8 months later!
 ORCA 4.2  ORCA 4.3 has also been frustrating.
Objectivity schema changed after July meeting, and it took
a while before it was made backward compatible with
previous DBs so that studies could continue to prepare for
L1 TDR studies
 Clearly development must occur, but it would help users if
the underlying architecture would stay stable

September 5, 2000
D. Acosta -- USCMS Physics Meeting
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U.S. Experience (3)
Some of this pain stems from none of the EMU
developers being based at CERN
 Attending the weekly RPROM meeting is not
enough. Must have a door to knock on to get advice.
 Long distance code development is slow, but most of
us have no other choice.
 Teaching duties, other active experiments, etc.
 Thus, EMU is not 100% ready at time of milestones
 Preliminary results shown by European colleagues
(using our code) mislead CMS Collaboration


i.e. Poor L1 efficiency in DT/CSC overlap, poor L1
PT resolution – lots of bad PR that demoralizes group
Having a larger U.S. base of users and developers
would improve efficiency of ORCA development

September 5, 2000
D. Acosta -- USCMS Physics Meeting
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Recent Results
Nevertheless, we have obtained some results on
L1 performance:
95%
Good efficiency in
DT/CSC overlap
region
September 5, 2000
D. Acosta -- USCMS Physics Meeting
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More Work Needed
L1 PT resolution shows difference between + and -
+
-
September 5, 2000
D. Acosta -- USCMS Physics Meeting
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Near-Term L1 & HLT Goals
Must get Endcap Muon code perfected so that we can
prepare efficiency and rate plots for the L1 TDR that are
representative of the system performance
 Last few bugs must be fixed


HLT Muon databases will be re-made with latest code
 No new MC needs to be produced in U.S. right now
 Caltech,
UCD, UFlorida have contributed CMSIM samples in
the past

Objectivity database formatting & Ntuple production
done at CERN without U.S. EMU involvement

Norbert and Anna have done a lot of work on this, and have
prepared the Ntuples used by the Muon groups. We should
be doing more of this, particularly in preparing standard
analysis jobs and Ntuples
September 5, 2000
D. Acosta -- USCMS Physics Meeting
9
Long-Term Plans
It would be nice to get the underlying EMU and L1
code finished so that we can move on to physics and
HLT algorithms!
 Hasn’t happened in parallel because the EMU
users are also the developers


My personal selection of topics:
 A fast L2 muon reconstruction package


Between that used by L1 and that used in offline analysis
A study of the reconstruction of muons in b-jets
Many important signals couple to b’s: Higgs, SUSY, …
 Accompanying punch-through debris will deteriorate
performance


Studies of your favorite physics topic that couples
to muons:
H4l, H, WH bb, ZH bb
 SUSY: +0  3l + MET
 Higgs:
September 5, 2000
D. Acosta -- USCMS Physics Meeting
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Summary
Clearly the Muon PRS group could use more
involvement from people in the U.S.
 Current members are over-stressed with demands
 Many more things we could be doing but haven’t


L2 algorithms, physics studies, …

Might be a good training ground for new students
before they commit to an analysis on CDF/D0
But there is a significant learning curve to overcome
to become effective
 Requires a lot of time, a lot of patience


We’ve started a good collaboration in the U.S.
 Future members shouldn’t have to suffer as much
as we did!
September 5, 2000
D. Acosta -- USCMS Physics Meeting
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