Working group on lifetime difference in the Bs system (Delta Gamma_s)

The aim of this working group is to compute the world average or combined limit for the fractional width difference (Delta Gamma_s/Gamma_s) in the Bs system.

Combination program

• DG_COMB program
• Inputs for PDG2003

Latest combined results

• Results proposed for PDG 2003:
  Changes: B0d lifetime (tauBd=1.537+-0.015), exclusion of the ALEPH meas. on phi-phi BRs (this measurement has been excluded in the present average because the theoretical assumptions are controversial and the systematic error due to the model is not quantified)
  • (Delta Gamma_s)/Gamma_s average with the B0d lifetime constraint
    
    • Results:
      
      • DG_s/G_s = 0.07+0.09-0.07
      • DG_s/G_s < 0.29 at 95% C.L.
    • Plots: (Figure-a ,  Figure-b ,  Figure-b with colours )
  • (Delta Gamma_s)/Gamma_s average without the B0d lifetime constraint
    
    • Results:
      
      • DG_s/G_s = 0.16+0.15-0.16
      • DG_s/G_s < 0.54 at 95% C.L.
    • Plots: (Figure-a ,  Figure-b ,  Figure-b with colours )

Previous Combined results

• Final results from Winter 2000 Conferences
  Draft
  Plot with taubd constraint (Figure-a, Figure-b, Figure-b with colours)
  Plot without taubd constraint (Figure-a, Figure-b, Figure-b with colours) <

  Results proposed for PDG 2000

  Draft

  Plot with taubd constraint (Figure-a, Figure-b, Figure-b with colours)

  Plot without taubd constraint (Figure-a, Figure-b, Figure-b with colours)

  Results proposed for PDG 2001

  Draft

  Plot with taubd constraint (Figure-a, Figure-b, Figure-b with colours)

  Plot without taubd constraint (Figure-a, Figure-b, Figure-b with colours)

  Results proposed for PDG 2002:
  

  Only the taubd lifetime has changed w.r.t. the 2001 pdg averages (tauBd=1.542+-0.016).

  The (Delta Gamma_s)/Gamma_s average, with the tauBd constraint, is 0.16+0.08-0.09.

  The allowed range for (Delta Gamma_s)/Gamma_s at 95% C.L. is [0,0.31]

  Plot with taubd constraint (Figure-a, Figure-b, Figure-b with colours)

  The average without the tauBd constraint remains unchanged.