Plans for Bs Mixing Analysis Meeting (May 12, 2005) - Franco Bedeschi & Joseph Kroll

1. Plans for Bs Mixing B Meeting 12 May 2005 Franco Bedeschi (INFN-Pisa) Joseph Kroll (Penn) Kroll/Bedeschi

2. Agenda of Discussion on 28 April 2005 Kroll/Bedeschi

3. Goals of this Discussion Find out who is doing what Questions for CDF Bs mixing analysis - What are the near term goals for Summer 2005? - What is the time scale and content of 1st publication? - How do we go from a limit to a measurement? We hoped the presentations and discussion today would help us understand the answers to these questions Decide on date of next workshop Kroll/Bedeschi

4. = on week Lepton Photon, Uppsala (4 on weeks) HEPP-EPS, Lisbon (5 on weeks) Calendar for Near Term Summer 2005 CDF Week, Sitges Kroll/Bedeschi

5. Planned Improvements & Extensions • Same-side kaon tag & fit with SST and OST • use muon versus two-track trigger data sample • Semileptonic decays in two-track trigger • improved proper decay time resolution • add more decay modes (e.g., Ds) • improve opposite-side tags (e.g., neural net jet charge) • add data after August 2004 • updated projections  Kroll/Bedeschi

6. Same-side Kaon Tag • Same-side kaon tag & fit with SST and OST • already had presentation (4/19) on unbinned fit with SST + OSTs • addition of SST increases fit time substantially • until Bs mixing observed, SSKT requires D from MC • cannot measure D from B0 & B+ • how will we evaluate systematics on predicted D from MC? • Check of B0 & B+ in data complicated by B** • Summary of discussion on 28 April • 2 groups working in parallel • requires detailed comparison between data and MC • evaluation of systematics requires many MC samples – will take time • mid-summer very ambitious – one group stated goal of end of summer • 2nd group reported plans and progress on 10 May 2005 Kroll/Bedeschi

7.  vs. two-track trigger data sample • vs. two-track trigger data sample • no prescale – recovers some TTT (with tag!) rejected by prescale • 120 pb-1 collected before August 2004 • CDF 7510: comparable sensitivity to 360 pb-1 TTT sample • continued implementation since December 2004 • As L increases, this may be our trigger path to observing mixing • should give high priority to analyzing this trigger path asap • look at post Fall 2004 shutdown data • should implement electron vs. TTT trigger path • Summary of discussion • SLT() more strict than trigger – same D • add trigger path to existing hadronic analysis • part of next public update of hadronic analysis • work on e vs. TTT planned – no timescale • should be included in high-PT trigger table Kroll/Bedeschi

8. Semileptonic Decays in TTT • Semileptonic decays in two-track trigger • identify e () down to 1 (1.5) GeV • softer lepton pT requirement than lepton + SVT trigger • significant addition of statistics (more than factor 2) • see presentation on 4/26 • has significantly larger fraction of fake backgrounds (WS fraction) • useful for studying fake leptons and semileptonic lifetime problem • Using in a mixing analysis requires complete re-evaluation of • signal optimization • K factors • SVT efficiency functions • physics backgrounds (e.g., B! Ds D) • fake contributions (larger WS fraction) • all associated systematics Kroll/Bedeschi

9. Semileptonic Decays in TTT • Summary of discussion and recent progress • two groups working in parallel • presentations at subgroup since 4/28 • 3 May 05 • showed signal statistics with likelihood based e and \mu identification • 1st presentation of physics backgrounds (B ! DsDX) • 10 May 05 • reoptimization of signals • significantly reduces WS and physics backgrounds while maintaining S • Excellent progress • both groups presented plans – no timescale provided • mid-summer very ambitious Kroll/Bedeschi

10. Improving Proper Decay Time Resolution • improved proper decay time resolution • add event-by-event primary vertex to hadronic analysis • this should be included in next public iteration • Summary of discussion • near term • update CDF7500 (e.g., 5.3.3 to 5.3.4, ebePV, hourglass beamline) • PV: implement time-dependent beamline parameters from DB • SV: study pull of d0 for 3rd track, e.g., K in J/ K • longer term: can we understand/improve scale factors? • lifetime resolution ultimate limitation on ms reach • need more effort here – e.g., silicon alignment Kroll/Bedeschi

11. Adding More Decay Modes • Summary of discussion • D modes • add D*3, D03 to B0 mixing analysis • add Ds3 to B0s mixing analysis • so far only BCHARM – add LOWPT path too (and +TTT?) • should be available for next public iteration Kroll/Bedeschi

12. Opposite-side Flavor Tags • improve opposite-side tags • neural net jet charge (CDF 7482) already blessed • other improvements underway • neural net SLT (see presentation 4/19) • improved muon likelihood (see presentation 4/26) • also seen recent reports on kaon tag (see presentationon 4/12) • Future improvements • Combination of OST • Summary of discussion • include blessed NN JQT in next public iteration • situation with NN proprietary software needs to be addressed Kroll/Bedeschi

13. Data after August 2004 • add data after August 2004 • When will we start including post Fall 2004 shutdown data? • particularly important for  + TTT path analysis • Summary of discussion and recent news • This data will not be available for Summer analysis • need to address problem of data processing with SPs • limitation is people for processing, updating calibrations etc. Kroll/Bedeschi

14. Updated Projections • updated projections • continually prompted for projections: when will we measure ms? • need update for Summer 2005 • (actually need update for next week: Oddone presentation) • important for evaluation of move from limit to measurement • Progress since workshop • produced update for Oddone • see http://www.cdf.fnal.gov/internal/spokes/RunIIb_Physics_Triggers/agenda_2005_05_10.html Kroll/Bedeschi

15. Updated Projection for EPP2010 5/16/2005 prepared for P. Oddone Discussion later today CDF Weekly Meeting Kroll/Bedeschi

16. Near Term Goals for Summer 2005 • Limited time for major summer conferences • 3 on-weeks until Lepton Photon • need to be ready to prebless in one month! • 4 on-weeks until HEPP-EPS • Do not want to decide in advance what is possible • however, we should focus on realistic goals • including ebePV in hadronics • update scale factors for lifetime resolution • adding modes like Ds (and similar modes for B0 analysis) • include  + TTT trigger in hadronic analysis • go to NN JQT Kroll/Bedeschi

17. 1st Publication and Measuring ms • First publication • Enormous overhead => wait until next iteration of analysis • use OSTs and possibly SSKT • include event by event PV • use current hadronic and semileptonic samples • may include new trigger paths or semileptonics in TTT path • timescale? (driven partially by career issues) • Observation of ms • We need to think about path to measuring mixing • limited in resources: physicists to do analysis • trigger challenge at higher luminosity Kroll/Bedeschi

18. Next Steps • Next B Mixing workshop is Thursday, 16 June 2005 • already having trouble booking a room • any analysis for LP05 will have already been preblessed • any analysis for HEPP-EPS will have to prebless following week • remember: by-laws say unblinding at preblessing • Need to make a list of tasks with schedule • especially need to identify personnel for near term summer goals Kroll/Bedeschi