Initial Physics and Plans for CMS

1. Matthew Jones (associate professor) David Silvers (graduate student – supported by NSF CAREER award) Early physics results ϒ production properties overlaps with CDF physics program Detector characterization using available data Absolute track reconstruction efficiency Longer term interests Trigger hardware upgrade Initial Physics and Plans for CMS http://www.physics.purdue.edu/~mjones/talks/mjones_cms_Aug_2010.ppt 2010 DOE virtual site visit

2. Physics Context • Involvement in CMS physics program is a natural extension of CDF interests: • Small data samples, but large cross sections. • Interesting physics questions that merit further investigation. • Extended rapidity coverage alone is very useful. • Analysis of muonic final states form a coherent effort at Purdue. • Purdue involvement has already influenced the structure of CMS analyses: strong emphasis on proven experimental techniques developed at CDF. 2010 DOE virtual site visit

3. Track Reconstruction Efficiency • Motivated by analysis which was patterned after the CDF J/ψ cross section measurement. • Allows muon/selection efficiencies to be determined using data rather than based entirely on Monte Carlo • Define muon selection/reconstruction efficiencies relative to tracking efficiency • Measure track reconstruction efficiency by embedding simulated hits in data events • Precision not limited by available statistics • Non-trivial interface with event data model • General interest in CMS, but in particular from the heavy ion group: very difficult to measure in any other way. 2010 DOE virtual site visit

4. Example from Track Embedding Analysis • Results from CMS AN-2010/209 and public TRK-10-002: • Tracking acceptance is well modeled by detector simulation. • Efficiency is high, but not accurately described by the simulation. • Differences may become increasingly important at high luminosity • Suggest sensitivity to local activity, ie. proximity to jets • This powerful framework allows detailed studies of these effects. • Complementary to other estimates of tracking efficiency which average over wide ranges of kinematic variables. • These results used to support a variety of analyses presented at ICHEP, but in particular were used directly in ϒ cross section measurement. Monte Carlo Data 2010 DOE virtual site visit

5. Longer Term Interests • Prior experience operating CDF at high instantaneous luminosity, L1/L2 hardware upgrades. • Infrastructure in place at Purdue for design and production of contemporary electronics systems. • Currently capitalizing on availability of good students from department of Electrical and Computer Engineering. • Interested in hardware development for extending L1 trigger capability at CMS. • Currently supported by NSF award, but overlaps with commitments to DOE. 2010 DOE virtual site visit

6. Example from Pixel Jet Trigger Studies • Construct Level-1 trigger primitives from sensors in barrel pixel detector: • Identify jets, measure η, φ and z-vertex position: achievable resolutions well matched to calorimeter segmentation. • Provide z-vertex position information to L1 calorimeter trigger • Controls rate of multi-jet triggers when multiple interactions per bunch crossing. • Studies performed using emulation of “implementable” hardware: • Fast pattern recognition in FPGA’s • Bandwidth constraints on existing fibers • Results presented at CMS upgrade workshop, October 2009. • However: • Currently unclear how this would fit in with upgrade efforts. • Strong support from Wisconsin, Fermilab: provides a way to learn about advanced trigger hardware before it becomes essential for CMS operations. • Less strong support from PSI: Why can’t we just increase jet trigger thresholds to control rates? • Long term plan must evolve with the evolving constraints on CMS upgrade efforts. 2010 DOE virtual site visit