1. B group status and plans Brad Abbott Sept 11, 2002

2. Very Near Term Trying to get number for average B lifetime (Earlier statement is that we are consistent with PDG) Addressing issues raised by EB Issues: Single/Double Gaussian for background Bias in vertexing J/Psi cross section Issues:Efficiencies

3. Very near term B group would like to have p12 available on the farms to allow us to use D0_mess(event stripper) This will allow us to generate large MC samples. Currently generating and verifying that p12 is working properly for B sample.

4. Near Term Studying different tracking algorithms MC Bs->Ds pi (Hadronic B decay) Bs->Ds e X (Semileptonic B decay) D*->D pi (Soft pion) J/Psi Ks (Ks reconstruction) Generic B decays

5. MC files These files allow us to see performance of many of the important issues needed for B physics. Event yields, pull distributions, vertex resolutions, flavor tagging etc. Efficiencies for various track definitions etc.

6. Tracking algorithms in Data J/Psi sample: Number of J/Psi, resolution, Psi`, B lifetime, B+ signal. Standard good run: Lambda, Ks, D->Kpi?

7. Triggers Many new triggers available for B physics: New dimuon triggers (studying performance) Trying to get a low Pt single muon trigger (needed for hadronic B decays -> Bs mixing). Best reach for  Ms for critical for large  Ms. Emphasis has been on muons No evidence of J/Psi in low Pt dielectron triggers.(2,2.5) EM trigger being prescaled away for now. Tracking trigger before low Pt electrons possible? Difficult to look at data from mu-e trigger since no criteria to search for low Pt electrons.

8. Muon ID Seeing low efficiency for using “Saclay” matching for J/Psi-> mu mu. Current matching is using ABC muons with Chisq>0 so does not work well for low Pt muons. Can track extrapolation code be sped up? Discussed with Gavin, some ideas are being investigated. Trying to find someone interested in pursuing this.

9. Other issues Streaming at L3: low Pt – high Pt stream, should be very useful for many B analyses. Have someone verifying streaming Would like ability to set bit to allow additional reco on interesting events. Being worked on.

10. Continuing to pick events Picking of interesting events (root files) Dimuons, single muons. These are often picked ~ 3 weeks after being written to tape. Picking of raw events, ~ 100/week to allow us to test latest reco code etc. Picking of small number of dimuon events soon after being collected to allow us to quickly see if problem with trigger, etc.

11. Other Issues Continuing to ensure that our code runs on thumbnails and contains necessary information for B physics Currently have 17 Thesis students working on B topics. Lambda_b, Chi_b, B_s mixing and Sin(2 Beta), CP violation

12. Walk before we can run Before we can do these analyses, we need to do more “bread and butter” physics. B lifetime, B+ signal, verify tagging performance, Bd mixing, Ks lifetime, Lambda lifetime. (Not as sexy so less interest from people, but necessary in order for people to believe our interesting results)

13. Conclusions Focusing on underlying issues: triggers, tracking, streaming etc. Results using muons encouraging, not so encouraging with electrons. Waiting for track trigger to increase data size.