BABAR Physics Working Group 12d ``Common Experimental Issues''

Assistant convener(s):
J. Frederic Kral, LBL, Phone: 1-510-486-7435, Fax: 1-510-486-5101, Email: JFKral@lbl.gov. Term: Rome workshop 1 through Princeton workshop 2.

Topics

1. Algorithms
   • Particle identification (lepton, charged hadron, neutral hadron)
   • Vertexing
   • Kinematic fitting
   • Tagging
   • Multivariate algorithms
   • Event selection cuts (e.g. shape cuts)
   • Background contamination
   • Detector imperfection and failures
2. Analysis at four-vector level
   • Angular analysis in vector channels (D*D*, J/psi K*, rho rho, etc.)
   • D and D* reconstruction for tagging and angle beta
   • Other standard particle reconstruction (J/psi, etc.)
3. Statistics
   • CP fitting: how to extract CP angles
   • Combining the results of several channels for one angle
   • Determining initial results with low statistics
   • Multi-variate analysis approaches in general
   • Setting up limits (Bayesian, Classical, etc.)
4. Systematics
   • Assembling a list of potentially dominating systematic errors
   • Charge asymmetry effects (e.g. pi+ versus pi- detector response)
   • Forward-backward asymmetry effects (e.g. B field, detector)
   • Tagging systematics
   • What aspects of systematics, if any, can we use the Monte Carlo for?
5. Running strategy
   • Running off the Upsilon(4S)
   • Scanning Upsilon(4S)
6. Strategy for making unbiased measurements
7. Computing requirements from CP physics
   • Monte Carlo generators
   • Simulation of detector response
   • Reconstruction
   • Event selection
   • Data access

Responsibilities and plan for work

• Physics/Reconstruction/Simulation Forum - [home page] - [discussion group] - This group has taken over the tools collection role of this page, wg12d.
• Workshop at Caltech - [Talk slides]

• Detector Simulation - Orsay group (M. Aslund, aslund@lal.in2p3.fr) [ASLUND web page] - [fastsim discussion]: this discussion contains things like better parameterization of EMC [item 40] (25 Mar 1997) and fix to pt cutoff at 170 MeV/c [item 41] (25 Mar 1997)
• CP Fitting - PAW fitting tool [group12b item 25] (Walter Toki, 5 May 1997)
• Workshop at Orsay - [Talk slides]

• Analysis in general - [Towards a Common Analysis Methodology] (Paul Harrison, Jan 2, 1997) [Beta Tutorial] (Charlie Young, February 1997)
• Vertexing - Make tool available and useful - Contact person is John Losecco - Follow-up on error matrix (Sciolla) - Use RecVtx package from Beta; it is based on the Slt package - [Vertexing in Beta] (John Losecco, Dec 2, 1996) - [Vertexing in Beta] (Bob Jacobsen, Dec 16, 1996) [`Vertexing' Neutrals] (John Losecco, Dec 18, 1996) - Vertexing finally works in Beta V00-04-05 [Announcement of vertexing fix] (Bob Jacobsen, Mar 2, 1997) - [Prelease of using TRACKERR errors] (Gabriella Sciolla, Mar 4, 1997)
• Kinematic fitting - Contact person is John Losecco - Group 12 investigation on kinematic constraints (Dubois-Felsmann) - Use squaw package that is released
• Event shape cuts - coding event shape variable calculations in Beta (Sebong Chun)
• Tagging - Use Cornelius package - Coordinated by Sophie Versille - Interface to Beta due March 1997 (A. Boucham)
• Particle ID - (need contact person) - People with Beta PID experience: Gloria Vuagnin, Peter Elmer
  • Experiment wide work
    • Uniform interface to leptons, charged hadrons, neutral hadrons - [Beta particle id interface to Aslund] (Gloria Vuagnin, Mar 6, 1997)
    • Leptons
      • e: tracking, dE/dx, EMC - QMW and other groups in UK
      • mu: tracking, IFR, (dE/dx, EMC) - IFR group
    • Charged hadrons
      • pi, K, p: tracking, dE/dx, DIRC, combining - PID group, contact: Maurice Benayoun
    • Neutral hadrons
      • K0S: tracking, vertexing, (dE/dx, DRC)
      • K0L, n: IFR - IFR group
  • Informal status in Beta (Mar 5, 1997)
    • Uniform Interface: class design exists in newest Beta release
    • DIRC: Aslund (OK), Reco (almost)
    • dE/dx: Aslund (OK), Reco (no)
    • IFR-muon: Aslund (almost), Reco (end March 1997)
    • EMC: Aslund (??), Reco (May 1997)
  • Group 12 work: Investigate what is in Beta - Anne-Marie Lutz
• CP Fitting - Provide new tool - Francois LeDiberder, Art Snyder, Gloria Vuagnin - [CP fitting plans] (LeDiberder, Dec 18, 1996) - [CP fitting with FBAD] (Walter Toki, Mar 7, 1997)
• Angular analysis of vector-vector CP states - Install into MC, develop analysis techniques - Walter Toki, Gloria Vuagnin
• Systematics - Each analysis to come up with list of sources of error
• MC Generators [Event Generators (hypernews)] - There is an "event generator group" lead by Walter Toki
  • Work with other working groups that are updating MC
    • Group 4 - [EvtGen for semileptonic decays (Group 4)] (Anders Ryd, Jan 11, 1997)
    • Group 6 - [Wg6: B Decay Models (main page)] [Wg6: Monte Carlo Generators (subpage)] - [Group 6 B Decay MC work plan] (Roland Waldi, Dec 19, 1996)
  • Time dependent CP violation
    • BEGET improvements (related to angular correlations) - issue being discussed in event generator group (Walter Toki, Anders Ryd and others) - [CP violating decay bug fix in BEGET] (Toki, Mar 4, 1997)
    • Francois LeDiberder and Sophie Versille are working on a B -> rho-pi generator with CP violation effects
  • BEGET and ASLUND
    • WARNING: don't use ASLUND's generator, use BEGET *always* since it is being maintained and bugs have been fixed.
    • How to write decay tables [.newdat how-to] (John LoSecco, Feb 22, 1997)
• Detector Simulation - Assemble single working ASLUND - Orsay group (aslund@lal.in2p3.fr) [ASLUND web page]
• ASLUND detector parameterization - Check and improve what is in ASLUND, or contact appropriate subsystem people
  • SVT - Diego Zanin - [beam pipe thickness] (Gerry Lynch, Nov 20, 1996)
  • DCH - Gabriella Sciolla
  • DRC - Walter Toki
  • EMC - Peter Sanders - progress can be found off the [Imperial Physics Analysis page] [EMCAslund page]
  • IFR - Maria Grazia Pia - [IFR in ASLUND] [ASLUND efficiencies] (Sept 20, 1996)
• Data store - interim solution to store ASLUND common block as an ntuple - Mehdi Benkebil [Storing ASLUND ntuples] (Dec 6, 1996) [ASLUND event store] (Dec 10, 1996) [ASLUND ntuple event store with Beta] (Feb 14, 1997) [Use ASLUND > V05-00-25 for read back] (Feb 26, 1997)
• Beta expert help - Bob Jacobsen
• Beta novice help - Some WG12 users of Beta can answer questions - Gregory Dubois-Felsmann, Remi Lafaye, John Walsh, Phil Strother
• Beta user discussion list - Paul Harrison - We have been asked to use the [Analysis Tools] discussion group
• BaBar Notes to be used for written communication
• Mock Data Challenge - Workshop group coordinators will ask for types and numbers of events (MDC1 due before May, 1997)
• Bug reports: use GNATS problem reporting (required) and pertinent hypernews groups (optional) - [GNATS Web interface] [GNATS user manual] - Bug fixes should go into CVS maintained released code
• Meetings - Group 12 met at SLAC on February 21, 1997
• Workshop at Princeton - Joint Group 12 meeting on March 18, 1997 [PRINCETON JOINT 12a+12b MEETING AGENDA] [Kral: Tools talk] [Kral: Tools scorecard slide] [All plenary talk slides]

References for Wg 12d

• BaBar Note References List

Finding references

• BaBar Notes Search Page
• BaBar note postscript file directory
• Submit BaBar Notes Search on CP Violation Physics
• Already performed search on all BaBar Notes (Warning: check date!)
• SPIRES HEP Database (e.g. find eprint hep-ph/9512341)

Related web pages and other help

• Physics/Reconstruction/Simulation Forum
• BaBar Physics Generators Group web page
• Beta analysis tool page
• Hints for running Beta analysis with BBSIM (Dominique Boutigny)
• Beta Tutorial page (Charlie Young)
• Tagging Group home page - [Cornelius package]
• Towards a Common Analysis Methodology (C++ classes) (Paul Harrison, Jan 2, 1997)
• ASLUND Web page (Orsay)
• GNATS bug reporting system
• Analysis Environment page (May 2, 1996) - [ASLUND: getting started (May 19, 1996)]
• Simulation home page