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Making the FTK Physics Case

Making the FTK Physics Case. M. Shochet 9/30/04. Fits into the ATLAS Trigger Architecture. on L1 accept. RODs. SCT  Pixels . FTK. “Level 1.5”. ROBs. ROBs. silicon hits. silicon tracks. ask for ROI’s. Level 2. Reaction to FTK.

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Making the FTK Physics Case

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  1. Making the FTK Physics Case M. Shochet 9/30/04 FTK meeting

  2. Fits into the ATLAS Trigger Architecture on L1 accept RODs SCT  Pixels  FTK “Level 1.5” ROBs ROBs silicon hits silicon tracks ask for ROI’s Level 2 FTK meeting

  3. Reaction to FTK • US: most I have spoken with: trigger is ATLAS weak spot • CERN: • TDAQ: focused on their immediate tasks, which are significant • Physics: leaders are very supportive • on the generic arguments as well as specific channels • Fabiola Gianotti: • Unlikely to find single channel that is accessible only with FTK • If find improvement in a number of channels, that is sufficient. Then the generic argument makes the case. • Giacomo Polesello: • If can be done, that would be enough. FTK meeting

  4. Why? The LHC will open a large new energy frontier. We are almost certain to find new physics there. But what that new physics is we don’t know. The way for us to be prepared to study that new physics with high sensitivity is to have the most powerful toolbox we can build. The ATLAS trigger is not as powerful as it could be. • ATLAS trigger has reasonable thresholds for e’s and ’s. • Jet trigger thresholds are very high because their raw rates are very large and there isn’t much you can do to reduce this in real time. FTK meeting

  5. J200 3J90 4J65 0.2 0.2 0.2 j400 3j165 4j110 25 Triggers without FTK Scenario: L= 2 x 1033deferral LVL1 selection LVL1 rate (kHz) HLT selection HLT rate (Hz) MU20 2MU6 0.8 0.2 m20 2m10 40 F. Gianotti, LHCC, 01/07/2002 ATLAS This is too large for objects in much of the mass range of interest. FTK meeting

  6. Why is this a serious problem? Whatever the source of EWK symmetry breaking, the role of the 3rd generation is likely to be big. (coupling  M; special role, …) • Pay attention to b’s and ’s. • ATLAS trigger is fine for 1st and 2nd generations: e, , inclusive jets •  thresholds are large; no e, ,  triggers • hard to reduce L1 jet thresholds to get more b-jet acceptance because it takes a long time to reconstruct in an Intel processor all the tracks in jets and find secondary vertices ( ) If we could have all tracks with PT > 2 GeV/c reconstructed near the beginning of L2, … FTK meeting

  7. Physics topics for Study • for measuring the b-jet response and resolution (-jet & Z-jet balance have theory/exp problems) for Mtop , MHiggs , … Problem: L1 trigger rate  higher jet ET threshold high threshold  high MJJ turn-on Solution: high PT Z’s • 3-jet trigger • highest ET jet is not tagged • bb opening angle not fixed near 1800  lower MJJ threshold FTK meeting

  8. Higgs Physics How much lower in tan can be reached? These jet PT’s are too low for existing triggers. How much does FTK help? FTK meeting

  9.  leptons • Need lower threshold for all  triggers. How low can the threshold be? • (Fabiola) • for the high PT response of TileCal across the detector • Existing thresholds (35/45 GeV) too high for W’s • (More general: isolated track triggers for calorimeter calibration – rapid level-2 rejection  higher level-1 rate) • (Ian) Existing  trigger is for 1-prong only. Polarization information requires seeing other  decay modes. FTK meeting

  10. More • (Ian)For electroweak production of anything that can be seen, masses will be low ( low PT jets). • (Michelangelo) B physics(if initial  is very low) ex, • General (Ian):redundancy in the trigger important for measuring efficiency FTK meeting

  11. What has to be done? What drives trigger decisions is background rejection, not signal efficiency. But background studies require LOTS of events. At 5 minutes/simulated event, … • Use fully simulated events to parametrize • jet response (with fluctuations) • jet trigger efficiency vs ET( especially at level 1) Use full simulation to check FTK track simulation: • hits (real & random), resolution Then can do convincing physics studies with fast simulation. FTK meeting

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