Planning for B s Mixing for Winter 2005

Planning for Bs Mixing for Winter 2005 Joseph Kroll (Penn) Franco Bedeschi (Pisa) Mixing Analysis Coordinators B meeting 16 September 2004 12/25/03 Manasquan, NJ

The Big Picture Goal: limit on (or measurement of) ms for Winter 2005 Winter 2005: La Thuile starts 2/27 Preferred MAC Winter activity  need to move La Thuile Must organize & direct effort now or will not have result Short time: this conference is only 5 ½ months from today Kroll/Bedeschi B Mixing Planning

Speaking of December 25, 2003: Chunhui got married that day in Las Vegas! Kroll/Bedeschi B Mixing Planning

Calendar We are here on week proposed B mixing workshop Collaboration meeting last Thursday meeting holiday La Thuile begins here Kroll/Bedeschi B Mixing Planning

Bs Mixing Ingredients • Reconstruct Bs signal with adequate signal to noise • semileptonic: lepton + Ds • hadronic: Ds, Ds • Measure Bs Lifetime • resolve lifetime problem in semileptonics • demonstrate lifetime measurement in SVT-biased hadronics • Identify Bs Flavor at production (flavor tagging) • challenge: estimating D for SST in Bs (for limit) • Demonstrate technique with B0 mixing (md) • use this step to calibrate opposite side flavor tags for Bs • require unbinned likelihood fit now • Measure (place limit on) ms also have the equivalent B0 & B+ signals calibration/check is B0 & B+ lifetimes Kroll/Bedeschi B Mixing Planning

HFAG:Current Experimental Results on ms Winter 2004 summary, PDG 2004 similar Kroll/Bedeschi B Mixing Planning

ICHEP 2004: Our Projected Sensitivity See M. Tanaka CDFNOTE 7170 v2.0 Uses full unbinned likelihood to estimate sensitivity for l Ds (more like 74 fs) Baseline: D2 = 1.6% (OST only)  = 67 fs (achieved) (OST is SLT(e) = 0.35% + SLT() = 0.7% + JQT = 0.5%) Stretch: D2 = 2.6% (add SST)  = 47 fs (L00, event by evt. PV) Kroll/Bedeschi B Mixing Planning

ICHEP 2004 Projected Sensitivity (cont) Hadronic Semileptonic Kroll/Bedeschi B Mixing Planning

ICHEP 2004 Projected Sensitivity (cont) Message: even with only OST may have sensitivity comparable to best experiment. Combined Kroll/Bedeschi B Mixing Planning

Highest Priority Items • Unbinned likelihood fit for md exploiting fully power • of flavor tags, event by event t, S/B in different modes, etc. to accomplish 1. we must 2. Resolve lifetime problem in semileptonic modes (l Ds) 3. Measure lifetime in SVT-biased hadronic modes (Ds, etc.) With blessed OST’s, 1, 2, & 3 may be enough to say something 4. Study SSKT – determine defensible D from data and MC in parallel with 1, 2, 3 Kroll/Bedeschi B Mixing Planning

1. Signals • Need to finalize our signal selections for basic modes • Semileptonic: • Selection is CDFNOTE 6780? • B0d modes: e/ + D0, D+, D*+ various D decay modes • B0s modes: e/ + Ds, with Ds! (K*K, ?) • Hadronic: • final selection? • B0d modes: J/ K*0, D+, , D*+(?) (also B+ modes for OST, lifetime check) • B0s modes: see list from projection study, add Ds? K*K can be used? • What is our data set? • 5.3.X • Data up to 8/23/04 excluding COT compromised data (which is?) • Do we have MC required for background/signal templates? Goal: present final signals at Collaboration meeting on 10/15/04 Kroll/Bedeschi B Mixing Planning

2. Lifetimes Timescale? • Need to understand semileptonic lifetimes • discrepancy has existed since Winter 2003 • see plan outlined later – and also talk by M. Tanaka today • Need to measure lifetime in SVT-biased hadronic modes • two groups (Oxford, Padova) asked to converge on common analysis • goal was to try for ICHEP – last presentations on 18 July 2004 • issues: SVT bias, determining resolution without prompt background • Need to check with unbiased J/ K signals • 1st signal from almost full data set shown (J/ K+ on 9/14/04) • not clear if anyone is looking at whole data set for lifetimes (J/ V0) • B! looking at whole J/ sample (Herndon) for resolution, PV, L00 Kroll/Bedeschi B Mixing Planning

Semileptonics Plan From discussion on 8 Sept 2004 Fast Kroll/Bedeschi B Mixing Planning

3. Flavor Tags • Use OSTs blessed for ICHEP: SLT(e), SLT(), JQT • put SLT(e) in repository, code clean-up for SLT() – all imminent • make OSTs mutually exclusive by construction (lepton L requirement) • apply to B+, B0 (semileptonic, hadronic) in unbinned L with D binning • are we getting projected 1.6%? • work on new tags/refinement (D*, OSKT etc.) okay – not for Winter 04 • Determine D for SSKT(big potential gain here) • need defensible prediction from MC of D if no oscillations observed • measuring particle content around B’s in data • need to compare to MC (generate larger sample) • issues: MC tuning, B** fraction in B0, B+, … • requires coherent, focused effort • present plan at next workshop on 1 October 2004 Timescale? Kroll/Bedeschi B Mixing Planning

4. Determining md to Check Procedure • This step implicit in previous slide on flavor tags • 1st step is unbinned likelihood lifetime fits • Two groups so far working on full mixing fit • MIT/Cantabria – showed J/ K* w SST at B semileptonics on 9/14/04 • Semileptonics lifetime group + CMU • Proposal: two independent groups check each other  common result • Fits must be validated with toy MC “data” • Issues (other than lifetime) • description of backgrounds – are we ready? • Okay on D correlation of flavor tags if OST made mutually exclusive • we need a timeline Kroll/Bedeschi B Mixing Planning

5. Amplitude Scan for ms • This has to be put together as well • assuming this will be done by groups on previous slide • Are we doing a blind analysis? • if so, how do we set it up (formulation)? • how do we organize it? Big brother will be watching you Kroll/Bedeschi B Mixing Planning

Required Tools (BPAK) • Start with tools as they are now • dE/dx • urgent issue: calibration of data after 13 February 2004 • TOF • urgent issue: calibration problem with time-walk correction • calibration for post 2/13/04 data needs validation • common PID • event by event primary vertex with L00 • being utilized by B! group • schedule for next tool upgrade is mid-November 2004 • Collaboration (Oct. 15th) meeting would be better goal Kroll/Bedeschi B Mixing Planning

Making a Schedule • At 3rd B mixing workshop on Friday, 1 October 2004 hope to present plan with names associated to tasks and timeline • this has been very difficult to achieve so far – especially the timescale • Based on constraints we make some general observations: • we better have the full fit working for B0d before 12/23/04 with all the necessary ingredients for B0s blessed • 1st two months of 2005 devoted to unblinding result on Bs, documenting, & blessing • are we publishing? early godparents? Can decide later. Kroll/Bedeschi B Mixing Planning

Blessings Along the Way • B signals (10/14/04?) • B lifetimes (11/11/04?) • combined OST efficiency & dilution (12/9/04?) • md (12/9/04?) • procedure for blinding and unblinding result on ms (12/9/04?) • SSKT  & D (in parallel with above) (prebless 12/9/04?) • result on ms (Collaboration meeting? 1/20/05?) • just use OST if SSKT not ready • Many potential publications along the way • relative BFs, lifetimes, fragmentation particles around B’s Kroll/Bedeschi B Mixing Planning

Summary and Plans • 3rd B mixing workshop planned for 1 October 2004 • trying to get a video room – usual problems • hope to present list of tasks and names with timescales • 4th and 5th workshops planned November, December • go to bimonthly meeting on off-week Thursdays? • Assume we need workshop or dedicated offweek meetings in January &/or February B Group must work coherently and be very focused You must take the initiative; do not wait for us to ask – keep us informed – and think about how you can help make this happen Kroll/Bedeschi B Mixing Planning

Planning for B s Mixing for Winter 2005