HFAG meeting, Nov 21, 2003

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Report from the lifetime/fraction/oscillation working group
about the status of averages for PDG 2004 
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Olivier Schneider


a) The new measurements to be included in PDG 2004 averages
   (compared to PDG 2003 averages) have been identified:
    - B0 lifetime from BABAR using inclusive D*pi and D*rho:
         B. Aubert et al., PRD 67, 091101R
    - B+ fraction from DELPHI:
         J. Abdallah et al, hep-ex/0311005), PLB 576, 29
    - dms from ALEPH (incl. lepton, Ds-lepton, excl. Bs)
         A. Heister et al., EPJC 29, 143
    New lifetime results from DELPHI have been submitted
    (CERN-EP-2003-065), but not accepted by the journal yet:
    these will not be include in the PDG 2004 averages.
    No new measurements of dmd.


b) Physics inputs needed:
   - chibar and BR(b->l) at LEP
     ---> new values provided by Klaus Moenig (LEP EW fit)
   - BR(B0->D-lnu), BR(B0->D*-lnu), BR(b->l) at B-factories:
     --> new values provided by Urs
   - other BRs:
     --> provided by PDG (unchanged compared to PDG 2003 ?)


c) Status of averaging work:
   - lifetimes, b-fractions and oscillation averages are performed
     (by  Lucia Di Ciaccio, Christian Weiser and Olivier Schneider)
     but still no Tevatron representative active in the lifetime averaging
   - DG averages:
      - Fabrizio Parodi ready to rerun DGs average (using new B0 lifetime)
      - Donatella Lucchesi investigating possibility of DGd average
   - still to be done:
      - check again semileptonic branching fraction averages (Urs) 
        using new lifetimes; if something changes, then iterate 
      - rerun DGs average (perhaps new DGd, but not very likely)
   - deadline at the end of Nov 2003 should be no problem, 
     but will provide final numbers asap


d) The current averages 
   (which are still missing the updated lifetimes and DGs) 
   can be seen in:
   http://lepbosc.web.cern.ch/LEPBOSC/combined_results/nov21b/
   http://lepbosc.web.cern.ch/LEPBOSC/combined_results/nov21b/WG.html
   Note that these are still preliminary
   (although the title of these pages say "PDG 2004 averages").


e) Most striking feature of new set of averages for 
   lifetimes, fractions and oscillation parameters is 
   that the Bs fraction is moving up:
   - will be around (10.7+-1.1)% for PDG 2004; 
   - would be (9.3+-1.1)% without the new chibar average
     from LEP EW (Klaus Moening), i.e. using the previous average
   - was (9.5 +- 1.0)% in Summer 2003, which already included 
     the new DELPHI B+ fraction, but not the updated value of chibar
   - was (10.0+-1.3)% in PDG 2003, and (10.6+-1.3)% in PDG 2002, 
     so the reader of the Particle Physics Review will not notice much
   The change in the new chibar average, from (11.84+-0.45)% to 
   (12.57+-0.42)%, is essentially due to the final OPAL result 
   which has changed from 0.111 to 0.1312+-0.0049+-0.0042
   (OPAL, G. Abbiendi et al., hep-ex/0308051)