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Hoi, I took the PDG2002 lifetime averages and calculate the BF for B0 and B+ from them. I get bfch := 0.10424 bfnu := 0.11316 You can check that they have the correct ratio (1.086) and average (0.1087). It's described below how I calculate it. On the BRECO Nsl sample (11582 B0 and 20583 B+), I find an effective BF = 10.75 (this is a 1.1% change) Weighting the lifetime according to the Nsl numbers, I get tau = 1.5895 Weighting the lifetime according to the Nu numbers, I get tau = 1.6021 Using these number for BF(B->Xu l nu) and |Vub| I find BF(Brecoil ->X l nu) tau BF(Brecoil -> Xu lnu) |Vub| ---------------------------------------------------------------------- 10.87 1.608 2.14 4.52 10.75 1.608 2.12 4.50 10.75 1.5895 2.12 4.52 10.75 1.6021 2.12 4.50 The BF changes by 1%, |Vub| correspondingly by 0.5%. It could be useful if someone would check this. Cheers, --U. #---------------------------------------------------------------------- # Lifetimes of B+ and B0 > tch := 1.542: > tnu := 1.674: > # B(B->Xlnu) > bf := 0.1087: > # Assume f+-/f00 = 1, i.e. sl BF is equally from B+ and B0 > f:= 0.5: > # Assume further b+/b0 = tch/tnu (with equal s.l. widths) # and then solve b = f*b+ + (1-f)*b0 for either b+ or b0 > bfch := bf / (f + (1-f)*tnu/tch); bfch := 0.1042384329 > bfnu := bf / (f*tch/tnu + (1-f)); bfnu := 0.1131615671 # Calculate the visible BF on the BRECO sample > nch := 20583: > nnu := 11582: > bfeff := (nch*bfch + nnu*bfnu) / (nch + nnu); bfeff := 0.1074514825 # Calculate weighted lifetime > teff := (nch*tch + nnu*tnu) / (nch +nnu); teff := 1.589530670