1. 1/14/05M. Shochet/NSF Site Visit1 Recent Work and Future Plans Faculty: Mel Shochet Postdocs:Taka Maruyama (now Tsukuba faculty) Erik Brubaker Grad Students:Jahred Adelman Shawn Kwang Undergraduates:Matt Baumgart Corrigan Nadon-Nichols CDF detector CDF analysis ATLAS detector

2. 1/14/05M. Shochet/NSF Site Visit2 CDF Detector Level-2 Upgrade (Shawn Kwang) –Run IIa level-2  trigger After ~2 years of run II operation, CDF still did not have a level-2  trigger. Pulsar could receive muon data and feed the existing L2 processors. Shawn: data zero suppression, track matching, algorithm code, monitoring The Pulsar worked extremely well: reduced the  trigger rate by  2 –Run IIb level-2 system on-line monitoring

3. 1/14/05M. Shochet/NSF Site Visit3 Silicon Vertex Trigger (SVT) –Hadron collider 1 st : generic selection of events containing b quarks B physics (ex. B s mixing) & high-P T physics (ex. Higgs) –Built largely by the Pisa and Chicago groups. –In 20  sec, finds all P T > 1.5 GeV/c tracks with offline quality impact parameter resolution. Impact parameter of primary tracks (cm)  : 50  m = 30  m (beam)  40  m (SVT)

4. 1/14/05M. Shochet/NSF Site Visit4 SVT operations –Very small group of experts Taka Maruyama had become the system expert in residence. The baton has been handed to Jahred Adelman. SVT upgrade –  ↑  silicon hit density ↑  more hit combinations in a track road  fit more track candidates  longer execution time  trouble! –Deadtime limited & SVT dominates L2 timing – narrower track roads & quicker fitting 32K roads → 512K (Pisa; LHC design) Pulsar: faster execution 5  10 31

5. 1/14/05M. Shochet/NSF Site Visit5 SVT Upgrade

6. 1/14/05M. Shochet/NSF Site Visit6 Chicago responsibilities –Project management (Shochet) –Produce Pulsars & mezzanine cards with large, fast memory (EDG) –Hit Buffers (Ivan Furic) Save hits at full resolution When a track road is found, send track fitter the hits –Track Fitters (Jahred Adelman with Un-Ki Yang) Fit track in ~200 nsec

7. 1/14/05M. Shochet/NSF Site Visit7 CDF Analysis: top quark properties Only elementary fermion to couple strongly to the source of EWK symmetry breaking (Yukawa coupling = 1.0) Measure couplings/properties: are any non-SM? Small cross section  large integrated luminosity Start with properties that need fewest # of events –tt production cross section –top quark mass Attack the major systematic: jet energy scale

8. 1/14/05M. Shochet/NSF Site Visit8 tt production cross section (Taka Maruyama) Standard background estimate: MC prediction for fraction of W+jets events containing a bb pair (major background for tt candidates with a tagged b-jet). Is it correct? Our technique: fit the sample to a sum of signal and background shapes. Background shape: W+jets with no b-tag (little top) –Should be the same (QCD Brehm spectrum) –Test in the W+1-jet and W+2-jet samples (little top)

9. 1/14/05M. Shochet/NSF Site Visit9 Leading jet E T (GeV) background top signal W+3p Wbb+1p Monte Carlo comparisons Wc+2pWcc+1p W+3p

10. 1/14/05M. Shochet/NSF Site Visit10 W+1,2-jet test Fit signal fraction, W+≥3 jets  = 6.0  1.6  1.2 pb (160 pb -1 )

11. 1/14/05M. Shochet/NSF Site Visit11 Top quark mass (Adelman, Brubaker) Template method described by YKK Adelman –Validating new reconstruction –Optimization of  2 cut (smallest expected  M ) –Testing new script-based fitter –Absolute jet energy corrections Sensitivity of parameterization on parent spectral shape

12. 1/14/05M. Shochet/NSF Site Visit12 Brubaker –Writing the PRD paper –Combining channels with non-gaussian statistical uncertainties and large correlated systematic uncertainties. Previously: likelihood combination with statistics, then consider systematics –Adding a channel with small stat  but large correlated syst  can make the final overall uncertainty worse. “Standard” methods like Blue require gaussian statistical uncertainties Now include the correlated systematics into the likelihood function

13. 1/14/05M. Shochet/NSF Site Visit13 Jet Energy Scale By far, the largest systematic uncertainty in the top mass (Higgs mass, …) In situ calibration of the calorimeter response to hadrons (Baumgart, Nadon-Nichols, Kwang) –Single track trigger + strict isolation 12-15 GeV hadrons ( data, single hadron simulation) (Had+EM)/P EM/PHad/PHad/P (min-I EM)

14. 1/14/05M. Shochet/NSF Site Visit14 Z→bb (Matt Baumgart) –fix the b-jet energy scale & resolution –SVT trigger (2 displaced tracks, 2 jets) –Poor S/B  need accurate background shape (below & above Z) –Low M JJ threshold  large trigger rate –Trigger rate was under control, but high   silicon hit density ↑  trigger rate  prescale trigger –Recently re-optimized trigger (lower  & weaker  dependence) (E 31)

15. 1/14/05M. Shochet/NSF Site Visit15 ATLAS – FTK hardware track trigger 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 good for 1 st and 2 nd generations: e, , incl. jets b jets and hadronic  ’s create a problem because generic jets have a very large cross section. –The level-1 trigger rates are kept low because it is difficult to reduce the rate at level 2. –It takes a long time to reconstruct in an Intel processor all the tracks in jets and find secondary vertices. (Si data loading, combinatorics) –If tracks were reconstructed by the beginning of level-2 processing, the picture is very different.

16. 1/14/05M. Shochet/NSF Site Visit16 RODsRODs SCT  Pixels  ROBsROBs ROBsROBs FTK on L1 accept “Level 1.5” silicon hitssilicon tracks Level 2

17. 1/14/05M. Shochet/NSF Site Visit17 The Event The Pattern Bank TRACKING WITHPATTERN MATCHING … Bingo scorecard

18. 1/14/05M. Shochet/NSF Site Visit18 Cluster finding Parallel pattern recognition that keeps up with full data rate out of silicon detectors. Fast track fitting (200 nsec in SVT upgrade) We must get the silicon hits, not disturbing the DAQ.  dual-output HOLA (S-Link driver) Designed, built, tested, approved by CERN.

19. 1/14/05M. Shochet/NSF Site Visit19 Next steps Prior to ATLAS approval, must document the physics case. – –  thresholds – for jet energy scale – Organizing a group to carry this (and FTK) out: Chicago Pisa Illinois Pennsylvania Argonne Rome Geneva

20. 1/14/05M. Shochet/NSF Site Visit20 US ATLAS Institutional Board The major challenge is getting US ATLAS physicists, who have largely been focusing on detector responsibilities, ready to do physics. Natural for the IB to play a major role here. Start discussions on organizing US physicists working in each ATLAS physics group. –Encourage collaboration: software expertise & physics topics –Have regular meetings convenient from East Coast to West Coast. –Make use of video conference technology to allow broad participation. –Regular reports to ATLAS physics groups.

21. 1/14/05M. Shochet/NSF Site Visit21 Next 3 Years CDF detector: complete upgrades, maintain performance CDF analysis: jet energy scale, top mass, top couplings &/or SVT-based searches ATLAS detector: FTK proposal, construction ATLAS analysis: help organize US ATLAS physics program