plans for b s mixing
DESCRIPTION
Plans for B s Mixing. B Meeting 12 May 2005 Franco Bedeschi (INFN-Pisa) Joseph Kroll (Penn). Agenda of Discussion on 28 April 2005. 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? - PowerPoint PPT PresentationTRANSCRIPT
12 May 2005 Kroll/Bedeschi 1
Plans forBs Mixing
B Meeting12 May 2005
Franco Bedeschi (INFN-Pisa)Joseph Kroll (Penn)
12 May 2005 Kroll/Bedeschi 2
Agenda of Discussion on 28 April 2005
12 May 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 todaywould help us understand the answers to these questions
Decide on date of next workshop
12 May 2005 Kroll/Bedeschi 4
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 2005 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
12 May 2005 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
12 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
12 May 2005 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
12 May 2005 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
12 May 2005 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
12 May 2005 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
12 May 2005 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
12 May 2005 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.
12 May 2005 Kroll/Bedeschi 14
• 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
Updated Projections
12 May 2005 Kroll/Bedeschi 15
Updated Projection for EPP2010 5/16/2005
Discussion later todayCDF Weekly Meeting
prepared for P. Oddone
12 May 2005 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
12 May 2005 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
12 May 2005 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