The Heavy Flavor Physics Program at CDF

1. The Heavy Flavor Physics Program at CDF http://www.physics.purdue.edu/~mjones/talks/mjones_Aug16_2006.ppt Matthew Jones (Assistant Professor) Gene Flanagan (Postdoc) Niharika Ranjan (Graduate student, M. Jones) Edwin Antillon (new Graduate student) Jeremy Mock, Steven Brunjes (Undergraduates) • Heavy Flavor Analysis • Time-of-Flight Maintenance • Triggers for Heavy Flavor Physics DOE Site Visit - Task A

2. Heavy Flavor Physics Analysis DOE Site Visit - Task A

3. Observation of Bs Oscillations DOE Site Visit - Task A

4. Observation of Bs Oscillations • Significant developments since last year: • Very successful running of the Tevatron: • Integrated luminosity more than doubled in 2005 • Successful operation of CDF: • SVX-II and COT operating well • Improved oscillation analysis: • Application of the Same-Side Kaon Tag • Purdue involvement: • Analysis of B0s-K and D+s-K corrlelations DOE Site Visit - Task A

5. Same Side Kaon Tag • Local quark flavor conservation in QCD • Expect more kaons around Bs mesons • Kaon charge identifies the initial Bs flavor • A primary motivation for building TOF detector! Original estimates based on Pythia (Lund string model):

6. Same Side Kaon Tag • The situation last year: • Looked promising, but was based entirely on a Monte Carlo model • Relied on aspects of fragmentation that have never been explicitly studied • Analysis of B0s-K correlations: • Look for the kaon that should be produced in association with B0s: • Do we find them? • Comparisons with Pythia? • Continued working with Denys Usynin (U. Penn) • Completed in October, 2005: Public CDF Note 8137 DOE Site Visit - Task A

7. B0s-K Correlation Analysis • Reconstruct semi-leptonic B decays: • Unfold sample composition • Calibrate Time-of-Flight for statistical separation of particle species • Using TOF+dE/dx, measure K/π/p/e fractions of particles produced near the B-decay DOE Site Visit - Task A

8. CDF Run II Preliminary K± around Bs K± around B0/B± CDF Data Pythia Monte Carlo B0s-K Correlations • Observe significantly more kaons around B0s compared with B0/B+: DOE Site Visit - Task A

9. Ds+-K Correlations • The level of agreement is surprising: • Why does Pythia do such a good job? • At what point do we see discrepancies? • How well do predictions scale with pT(B)? (Particularly important for ACP in BsJ/ψφ, BsJ/ψƞ) • These questions cannot be adequately explored using B0s decays • Instead, study particles produced in association with prompt D+s mesons • N. Ranjan thesis topic (also on call TOF expert) presented at APS DOE Site Visit - Task A

10. New Directions • B0s oscillations now observed • We were lucky that Δms ~ 17 ps-1 • Published significance will soon be >5σ • De-emphasize work to facilitate discovery • Next: ACP in BsJ/ψφ and BsJ/ψƞ • Even a 30% measurement would be extremely interesting • Work on search for BsJ/ψƞ begin with Edwin Antillon (MARC/AIM summer research program). • Important and currently unexplored aspect of B0s decays: pure CP eigenstate, important lifetime measurement DOE Site Visit - Task A

11. Time-of-Flight Operations DOE Site Visit - Task A

12. Time-of-Flight Operations • Co-project leader since 2001, now fully responsible for TOF operations • Responsible for electronics maintenance • Analysis interests drive further understanding of the TOF system: • Calibration: CDF Notes 6948, 7620 • Alignment: CDF Note 7693 • Non-routine operation issues: • Evidence for significant aging of a subset of PMT’s used (related to alignment analysis) • Now coordinating the work to understand the effect, and learn how to operate TOF in the remainder of Run II. DOE Site Visit - Task A

13. Time-of-Flight Operations • TOF is essential for several aspects of B-physics analyses (kaon tags, particle ID) • Past institutional involvement: Penn, MIT, FNAL, Berkeley Japan, Italy, Korea, Spain • Current MOU’s with CDF: Purdue (electronics), Spain (calibration) • Limited contributions from other institutes: Penn, Italy provide additional pager coverage DOE Site Visit - Task A

14. Aging of TOF PMT’s • Unambiguous metric for PMT response: Does a minimum ionizing particle traverse enough scintillator to fire the discriminator? DOE Site Visit - Task A

15. Bad Bad Good Good Good Gain loss vs PMT serial number • Assumes that serial numbers correlate to manufacturing date (probably reasonable). Received PMT’s from Hamamatsu in 6 batches. DOE Site Visit - Task A

16. Plan for TOF Operation • Removed several PMT’s from detector during the last shutdown • Compare good/bad PMT’s • Working with Hamamatsu via colleagues in Tsukuba • Increase HV on channels with largest loss of response – watch for further loss. • Change operating point for front-end readout electronics: • Lower discriminator thresholds (very low noise floor) • Increase ADC gate width • Complete studies this year, decide on operating strategy for 2007-09. DOE Site Visit - Task A

17. Trigger Upgrades DOE Site Visit - Task A

18. Heavy Flavor Triggers • Recognized that most analyses at CDF would be limited by trigger performance: • Especially true for hadronic B-decay triggers • Now important for multi-jet, missing ET • Developed new method for extrapolating trigger rates to high luminosity • CDF note 7356 (still in use) • Argued against luminosity leveling: • FERMILAB-TM-2322-AD-E • Jointed effort to upgrade XFT system • Especially important for B-physics triggers • Purdue responsible for front-end readout and calibration software (Flanagan) • Efficiency studies motivated reducing COT wire thresholds DOE Site Visit - Task A

19. XFT Upgrade Hits on axial wires Pattern of hits identifies a track segment Pattern of track segments identifies a track (pT,φ) Over efficient: when occupancy is high, all possible patterns of hits will be identified  Fake XFT tracks. Solution: Add information from stereo superlayers DOE Site Visit - Task A

20. July 11th: First evidence of a working system More recently: measuring pixel/track finding efficiencies Remaining issues: low level error rate in axial-stereo track confirmation XFT Commissioning DOE Site Visit - Task A

21. Beyond the XFT Upgrade • XFT upgrade provides a way to get a list of tracks into new level 1 trigger hardware • Significant benefit to B-physics program: Multi-body hadronic B-trigger that includes the φK+K- decay topology • Demonstrated improvement in B0s oscillation analysis: perhaps double the yield by 2009. DOE Site Visit - Task A

22. Level 1 φK+K- Trigger • One of several “Beyond-the-baseline” trigger upgrades presented for review on May 12 (CDF trigger workshop) • Institutional involvement: Purdue, FNAL, University of Illinois, Carnegie Mellon • Main concerns were the level of engineering support for firmware development and timing constraints DOE Site Visit - Task A

23. Level 1 φK+K- Trigger • Worked with Steven Brunjes (Electrical Engineering undergraduate) • Demonstrated timing feasibility: 100 ns to analyse all possible pairs of tracks DOE Site Visit - Task A

24. Level 1 φK+K- Trigger • Final outcome: • The trigger is feasible • It would enhance the B-physics program • But: • Benefits would not be overwhelming • Would no longer directly impact physics analysis at Purdue • There are more important places to use limited resources • Not ruled out: • Still an ideal project for undergraduate/graduate student DOE Site Visit - Task A

25. Calorimeter Trigger Upgrade • Natural transition to Level 2 calorimeter trigger upgrade: • Original jet trigger rate extrapolations (2004) • Trigger representative for QCD group (Flanagan) • Limitations of current level 2 missing ET trigger (Veszpremi) • Will continue to play key role in calorimeter trigger upgrade (talk by Flanagan) DOE Site Visit - Task A

26. Summary • CDF is an important aspect of the heavy flavor physics program at Purdue • Several important measurements are now possible before LHC-b dominates the field • Demonstrated importance of TOF detector: working to maintain optimal performance • Trigger has always been a moving target: essential to maintain close connection with analysis interests. DOE Site Visit - Task A