Meeting Notes for 14 January 2010 (CMS meeting at ND)

Present: Marge, Liz, TomJ, TomL, Randy, DanK, Phong, Mihael

Due Dates

  • In production by 1 June
  • Get a beta by 1 April


  • We learn to make claims based on discovery - evidence
    • How unstable particles can be detected through decays to stable particles and how measuring properties of stable → properties of unstable
      • How to see the ephemeral
      • How particles interact with the detector
  • How we gain confidence in measurements
    • Concepts of signal and background
  • How discoveries happen over time
  • What is fundamental

Learning the process of discovery

  1. How particle physics makes and build confidence about discoveries
    1. Because the detector we use for discoveries is "working"
      1. I know that it is working because it confirms known results (previously found)


  • Explain the role conservations rules play in analyzing data
  • Provide an answer to the research question and support it with evidence
  • Differentiate between signal and background
  • Apply appropriate conservation rules to the dimuon events
  • Explain the significance of the location and shape of the "bump" and how the histogram fills
  • Explain the measurement of properties of less stable particles by the observation of the properties of more stable particles
  • Describe which particles were involved in these events
  • Draw and annotate a diagram of CMS

  • Get an image bank of event displays from Fireworks

Why are dimuon events interesting?

  • Z0 is neutral - students probably know about charge conservation (hopefully?)
  • For new things? Could have different charges
  • How to identify the charges? Need transverse energy plots
  • For dimuons, need the vector <Px, Py, Pz, E> (E = √(P2 + m2)), charge (Q), particle ID (e, μ, etc.), event number, timestamp
  • 900 GeV data should be available quickly
    • 1M events on tape - but not too many J/ψ events?
    • Might have data by 1 Jun. Might.
  • Should we just go forward with Monte Carlo data?

Training component (bootcamp) for new collaborators

  • Some of the dimuon events, J/ψ, etc. used for this
  • Will use DanK's OGRE.


  • Presently OGRE grabs pre-generates plots in the data
  • Going to need a CMS data module to do our own plots
    • This is CPU-intensive
    • Cache old results
  • Can make a preprocessed file - but makes it a pain in the rear to do something new
    • Could save that preprocessing as some external metadata file (adding to instead removing)
  • We will have mass plots
    • Later transverse momentum

Research Questions

  • MC or rundata? That'll affect things
  • For MC data? Look at the bumps, ask what's going on
  • For rundata? Ask "is the detector working" - issues with plots over time for statistical certainty
  • Plots & timestamps

Design Requirements


  • Image bank of event displays
  • Plot overlays
  • Mass plots: μ+μ-, μ±μ0, Pt
  • Save plot history+values, mass and standard deviation
  • Annually produce collaboration mass and standard deviation
    • Compare against mass, SD on all data
  • Make cuts
  • Re-run plots (with required provenance, metadata, etc)
  • Fast forward time "fill" (animation, 3D chart)
  • Separate signal from background
  • Px, Py, Pz, ...
  • Mechanism to choose the grid or local cluster or server
  • Teacher approval for the poster
  • Revised poster (the specialized pre-filled one for CMS)
  • Add or unlock data month-by-month (MC at first, later rundata?)
    • Note the latest data update timestamp


  • Discovery science
  • Role of conservation rules
  • Standard model particles
  • Stable, unstable
  • Label diagram of the detector
  • Signal, background
  • Plot shape, location, meaning of the numbers
  • Know how tu support the research question with evidence
  • Hypothetical production of Z

Misc Notes

  • Dimuon events - how to frame it for student understanding?
  • For teachers without much time - very high level investigation. Just invariant mass distribution
    • More time? Maybe do more.

-- Main.PhongNguyen - 14 Jan 2010

* CMS_eLab_First_Concept.rtf: CMS_eLab_First_Concept.rtf
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Topic revision: r75 - 2010-01-14, PhongNguyen
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