planning for b s mixing for winter 2005

Planning for Bs Mixing for Winter 2005

Joseph Kroll (Penn)Franco Bedeschi (Pisa)

Mixing Analysis CoordinatorsB meeting 16 September 2004

12/25/03 Manasquan, NJ

16 September 2004 Kroll/Bedeschi B Mixing Planning 2

The Big Picture

Goal: limit on (or measurement of) ms for Winter 2005

Winter 2005: La Thuile starts 2/27

Short time: this conference is only 5 ½ months from today

Must organize & direct effort now or will not have result

Preferred MAC Winter activity need to move La Thuile


Speaking of December 25, 2003: Chunhui got married that day

in Las Vegas!


Calendar

on week

proposedB mixingworkshop

Collaborationmeeting

last Thursdaymeeting

We are here

La Thuile begins here

holiday


• 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

Bs Mixing Ingredients

also have the equivalent B0 & B+ signals

calibration/check is B0 & B+ lifetimes


HFAG:Current Experimental Results on ms

Winter 2004 summary, PDG 2004 similar


ICHEP 2004: Our Projected Sensitivity

Baseline: D2 = 1.6% (OST only) = 67 fs (achieved)

Stretch: D2 = 2.6% (add SST) = 47 fs (L00, event by evt. PV)

Uses full unbinned likelihood to estimate sensitivity for l Ds

See M. Tanaka CDFNOTE 7170 v2.0

(more like 74 fs)

(OST is SLT(e) = 0.35% + SLT() = 0.7% + JQT = 0.5%)


ICHEP 2004 Projected Sensitivity (cont)

Hadronic Semileptonic


ICHEP 2004 Projected Sensitivity (cont)

Message: even with only OSTmay have sensitivity comparableto best experiment.

Combined


Highest Priority Items

1. Unbinned likelihood fit for md exploiting fully power of flavor tags, event by event t, S/B in different modes, etc.

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

to accomplish 1. we must

in parallel with 1, 2, 3 4. Study SSKT – determine defensible D from data and MC


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


2. Lifetimes

• 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

Timescale?


Semileptonics Plan

From discussionon 8 Sept 2004

Fast


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?


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


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


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


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 B0

d before 12/23/04 with all the necessary ingredients for B0

s blessed

– 1st two months of 2005 devoted to unblinding result on Bs, documenting, & blessing

– are we publishing? early godparents? Can decide later.


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


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 focusedYou must take the initiative; do not wait for us to ask – keep usinformed – and think about how you can help make this happen

planning for b s mixing for winter 2005

Documents

b modes

b0d modes

semileptonic modes

lifetime checkb0s modes

different modes

svtbiased hadronic modes

defensible d

measure lifetime