Physics Progress in CMS

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Physics Progress in CMS
Jim Branson US CMS Physics Coordinator DOE/NSF
Review January 17, 2003
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SC Vital for CMS Physics

• Huge physics dataset
• Large number of physicists performing hundreds of
  analyses.
• Unprecedented data access problem
• Complex events
• Possibility of instant discoveries
• High resolution needed in discovery channels
• Have been working with OO software for DAQ TDR
• Full simulation and digitization with pile-up
• C reconstruction code ORCA
• Stick with OO code even if this would meant
  delays
• Switching to OO Geant4 Simulation now
• Switching to Grid-based production now
• Software tested by hundreds of users

Major Milestone
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HLT Software Gives Last Factor of 1000

• Software to process 100 kHz of highly complex
  events for HLT.
• Physics selection of 100 best events per second.
• Must migrate offline code to HLT very
  efficiently.
• Same software

100 kHz
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Luminosity for a 5s Higgs Signal

• 5 sigma signal possible in one year of running
  from 100 GeV to 600 GeV.
• From 150 to 450, 5 sigma effect could come in a
  few months.
• WW and ZZ() using leptons
• Hardware trigger and software must be ready at
  the beginning of running.
• CMS has advantages for most difficult region.

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SUSY in one week

• High energy can pay off immediately.
• Squark gluino search starts the first day of
  running.
• Missing energy plus jets.
• Not the CMS strong suit.
• Need tracker to measure jets and missing energy
  well.

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PRS Organization for DAQ TDR

• Physics Reconstruction Selection (PRS) groups
• Groups were put in place in April 99, formalized
  within each detector group with the start of CPT,
  end of 2000.
• Since Jan 2001, four groups
• ECAL-Electron/Photon C. Seez
• Muons U. Gasparini/D. Acosta
• HCAL-Jet/Missing ET S. Eno/S. Kunori
• TRACKER-b/t (vertex) M. Mannelli/L. Silvestris
• Charge create CMS detector, reconstruction and
  simulation software evaluate full chain (from
  Lvl-1 to offline) of physics selection for CMS.
  First priority the HLT
• study, design implement algorithms and code to
  provide the rejection/efficiency needed for CMS
  physics plan
• Plan to continue with these groups plus fast
  simulation as we work toward Physics TDR (and
  Data Challenges)

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ORCA/HLT Production

• HLT studies use full simulation and
  reconstruction of high luminosity LHC events.
• 17.3 minimum bias events per crossing.
• 9 crossings contribute to calorimeter
  digitization (out of time pileup).
• Event sample sizes 5 million background
  signal events.
• Massive data moving exercise 150 minimum bias
  events randomly chosen from a sample of 100k and
  with a size of 35MB for every signal event (1MB).
• One CMS event requires of order 100-400 times
  more computing to digitize than one RUN II
  event.

25 nsec
25 nsec
25 nsec
25 nsec
25 nsec
25 nsec
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Physics Content of Muon Triggers
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W??? Efficiency
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Electron HLT Jet Rejection with Pixels
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Track Reconstruction Efficiency
Algorithmic
Global
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Track Momentum Resolution
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Track Vertex Resolution
Impact Parameter
z coordinate
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B Tagging in HLT
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Level 1 Trigger Rates at 2X1033
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Level 1 Trigger Rates at 1034
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HLT Rates at 2X1033
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HLT Execution Times at 2X1033
Assumes 1 GHz PIII
Manageable HLT Farm Size
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Post-DAQ-TDR Physics

• Physics TDR will also be a readiness test for
  collaboration and for groups.
• Important for US to perform well
• Many US groups worked on HLT for TDR
• Several post-TDR Analyses started in US groups
• Drell-Yan, Z at UCLA
• H??? at UCR
• H??? at Caltech and UCSD
• New studies with forward jets
• Jet Physics at FNAL
• Need more US tracker activity

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Photon Energy Resolution for r9gt0.92
11500 photons with 0.74 resolution Very similar
to unconverted photons.
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Reconstructed Mass r9gt0.92
Division into categories Includes most
unconverted photons plus many others which also
have good resolution.
Includes linear correction of S25 for S1/S9
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US CMS Physics Coordination

• All CMS PRS groups have made their meetings
  available to us.
• Reasonable level of US participation
• Monthly US meetings to coordinate our activities.
• User input to Software and Computing project.
• US PRS users have been very satisfied with
  support from Software and Computing project.
• US physics analysis discussions
• Need to ramp up base program participation in
  physics this year in preparation for Physics TDR.
• Split positions with running experiments?

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Summary

• For many reasons, Software and Computing is very
  important for Physics in CMS and for US Physics
  leadership.
• We have passed a major milestone with the
  completion of the DAQ TDR in November.
• Large, complex production of tens of Terabytes of
  data.
• Used current OO software for Reconstruction and
  Analysis.
• Many high quality results including good
  understanding of L1 trigger rate, event size, and
  HLT trigger rates.
• DC04 and Physics TDR in 2005 will test readiness
  of CMS and US collaboration.
• Some analysis started in US, but not nearly
  enough.
• Need to ramp up base program this year.

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US is Largest National Group in CMS
USA
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Jet Improvements Using Tracks
Improved Resolution
Improved raw Energy Scale