12 May 2005Kroll/Bedeschi1 Plans for B s Mixing B Meeting 12 May 2005 Franco Bedeschi (INFN-Pisa) Joseph Kroll (Penn)

12 May 2005Kroll/Bedeschi2 Agenda of Discussion on 28 April 2005

12 May 2005Kroll/Bedeschi3 Goals of this Discussion Find out who is doing what Questions for CDF B s mixing analysis - What are the near term goals for Summer 2005? - What is the time scale and content of 1 st 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

12 May 2005Kroll/Bedeschi4 Calendar for Near Term Summer 2005 = on week Lepton Photon, Uppsala (4 on weeks) HEPP-EPS, Lisbon (5 on weeks) CDF Week, Sitges

12 May 2005Kroll/Bedeschi5 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., D s  ) improve opposite-side tags (e.g., neural net jet charge) add data after August 2004 updated projections 

12 May 2005Kroll/Bedeschi6 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 B s mixing observed, SSKT requires D from MC cannot measure D from B 0 & B + how will we evaluate systematics on predicted D from MC? Check of B 0 & 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 2 nd group reported plans and progress on 10 May 2005

12 May 2005Kroll/Bedeschi7  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-P T trigger table

12 May 2005Kroll/Bedeschi8 Semileptonic Decays in TTT Semileptonic decays in two-track trigger –identify e (  ) down to 1 (1.5) GeV –softer lepton p T 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 ! D s D) fake contributions (larger WS fraction) all associated systematics

12 May 2005Kroll/Bedeschi9 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 –1 st presentation of physics backgrounds (B ! D s DX) 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

12 May 2005Kroll/Bedeschi10 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., to 5.3.4, ebePV, hourglass beamline) PV: implement time-dependent beamline parameters from DB SV: study pull of d 0 for 3 rd track, e.g., K in J/  K –longer term: can we understand/improve scale factors? lifetime resolution ultimate limitation on  m s reach need more effort here – e.g., silicon alignment

12 May 2005Kroll/Bedeschi11 Adding More Decay Modes Summary of discussion –D  modes –add D * 3 , D 0 3  to B 0 mixing analysis –add D s 3  to B 0 s mixing analysis –so far only BCHARM – add LOWPT path too (and  +TTT?) –should be available for next public iteration

12 May 2005Kroll/Bedeschi12 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

12 May 2005Kroll/Bedeschi13 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.

12 May 2005Kroll/Bedeschi14 updated projections –continually prompted for projections: when will we measure  m s ? –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 agenda_2005_05_10.html Updated Projections

12 May 2005Kroll/Bedeschi15 Updated Projection for EPP2010 5/16/2005 Discussion later today CDF Weekly Meeting prepared for P. Oddone

12 May 2005Kroll/Bedeschi16 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 D s  (and similar modes for B 0 analysis) include  + TTT trigger in hadronic analysis go to NN JQT

12 May 2005Kroll/Bedeschi17 1 st Publication and Measuring  m s 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  m s –We need to think about path to measuring mixing –limited in resources: physicists to do analysis –trigger challenge at higher luminosity

12 May 2005Kroll/Bedeschi18 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